SCHEDULE 14A

                                 (RULE 14A-101)

                    INFORMATION REQUIRED IN PROXY STATEMENT

                            SCHEDULE 14A INFORMATION

                  Proxy Statement Pursuant to Section 14(a) of
                      the Securities Exchange Act of 1934


              
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      Filed by a Party other than the Registrant / /

      Check the appropriate box:
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                 BY RULE 14A-6(E)(2))
      /X/        Definitive Proxy Statement
      / /        Definitive Additional Materials
      / /        Soliciting Material Pursuant to Rule 14a-11(c) or Rule
                 14a-12

                                   AMERICAN TOWER CORPORATION
      -----------------------------------------------------------------------
                 (Name of Registrant as Specified In Its Charter)

      -----------------------------------------------------------------------
           (Name of Person(s) Filing Proxy Statement, if Other Than the
                                    Registrant)


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                                     [LOGO]

                                                                  March 30, 2001

Dear Stockholder:

    It is a pleasure to invite you to the Company's 2001 Annual Meeting in
Boston, Massachusetts on Thursday, May 17, 2001 at 10:00 a.m., local time, at
the offices of Hale and Dorr LLP, 60 State Street, 26th floor, Boston,
Massachusetts 02109. Registration for the Meeting will begin at 9:30 a.m. The
official Notice of Meeting, proxy statement and form of proxy are included with
this letter. The matters listed in the Notice of Meeting are described in detail
in the proxy statement.

    The vote of every stockholder is important. Therefore, I urge you to sign
and date the enclosed proxy card and promptly return it in the enclosed envelope
so that your shares will be represented at the meeting. Alternatively, you may
also vote your shares over the Internet. Please refer to the enclosed proxy card
for detailed instructions. You may withdraw your proxy and vote in person at the
meeting if you wish to do so.

    Your Board of Directors and management look forward to greeting those
stockholders who are able to attend.

                                          Sincerely,

                                          /s/ Steven B. Dodge

                                          Steven B. Dodge
                                          CHAIRMAN OF THE BOARD, PRESIDENT AND
                                          CHIEF EXECUTIVE OFFICER

                           AMERICAN TOWER CORPORATION
                             116 HUNTINGTON AVENUE
                          BOSTON, MASSACHUSETTS 02116

                            ------------------------

                 NOTICE OF 2001 ANNUAL MEETING OF STOCKHOLDERS
                           TO BE HELD ON MAY 17, 2001

                             ---------------------

To the Stockholders:

    The 2001 Annual Meeting of Stockholders (the "Annual Meeting") of American
Tower Corporation, a Delaware corporation ("American Tower" or the "Company"),
will be held at the offices of Hale and Dorr LLP, 60 State Street, 26th floor,
Boston, Massachusetts 02109 on Thursday, May 17, 2001 at 10:00 a.m., local time,
to consider and act upon the following matters:

       1.  To elect eight directors, including two Class A directors to be
           elected by the holders of Class A Common Stock voting separately as a
           class, for the ensuing year or until their successors are elected and
           qualified;

       2.  To approve an amendment to the Company's Amended and Restated 1997
           Stock Option Plan to provide for automatic annual increases in the
           number of shares authorized for issuance thereunder;

       3.  To ratify the selection by the Board of Directors of Deloitte &
           Touche LLP as the Company's independent auditors for 2001; and

       4.  To transact such other business as may properly come before the
           meeting or any adjournment or adjournments thereof.

    Stockholders of record at the close of business on March 26, 2001 are
entitled to notice of, and to vote at, the Annual Meeting. The stock transfer
books of the Company will remain open for the transfer of the Company's Common
Stock. For a period of ten days prior to the Annual Meeting, a complete list of
the stockholders entitled to vote at the Annual Meeting will be available at the
offices of the Company for inspection by any stockholder of record for any
purpose germane to the Annual Meeting.

                                          By order of the Board of Directors,

                                          /s/ Jonathan R. Black

                                          Jonathan R. Black
                                          SECRETARY

Boston, Massachusetts
March 30, 2001

 WHETHER OR NOT YOU EXPECT TO ATTEND THE ANNUAL MEETING, PLEASE COMPLETE, DATE
 AND SIGN THE ENCLOSED PROXY CARD AND PROMPTLY MAIL THE PROXY CARD IN THE
 ENCLOSED ENVELOPE IN ORDER TO ASSURE REPRESENTATION OF YOUR SHARES AT THE
 ANNUAL MEETING. NO POSTAGE NEED BE AFFIXED IF THE PROXY CARD IS MAILED WITHIN
 THE UNITED STATES. ALTERNATIVELY, PLEASE VOTE OVER THE INTERNET BY FOLLOWING
 THE INSTRUCTIONS ON THE ENCLOSED PROXY CARD.

                           AMERICAN TOWER CORPORATION
                             116 HUNTINGTON AVENUE
                          BOSTON, MASSACHUSETTS 02116

                            ------------------------

                                PROXY STATEMENT
                  FOR THE 2001 ANNUAL MEETING OF STOCKHOLDERS
                           TO BE HELD ON MAY 17, 2001

                             ---------------------

                              GENERAL INFORMATION

    This Proxy Statement is furnished in connection with the solicitation of
proxies by the Board of Directors (the "Board of Directors") of American Tower
Corporation, a Delaware corporation ("American Tower" or the "Company"), for use
at the 2001 Annual Meeting of Stockholders (the "Annual Meeting") to be held on
May 17, 2001 or at any adjournment or postponement thereof.

    The Company's Annual Report to Stockholders for the fiscal year ended
December 31, 2000 is being mailed to stockholders with the mailing of this Proxy
Statement on or about April 9, 2001.

RECORD DATE, VOTING RIGHTS AND OUTSTANDING SHARES

    The Board of Directors has fixed March 26, 2001 as the record date for
determining holders of the Company's Common Stock who are entitled to vote at
the Annual Meeting.

    The Company has three classes of common stock issued and outstanding:
Class A Common Stock, $.01 par value per share, Class B Common Stock, $.01 par
value per share, and Class C Common Stock, $.01 par value per share (the
Class A Common Stock, the Class B Common Stock and the Class C Common Stock are
collectively referred to as the "Common Stock").

    With respect to the matters submitted for vote at the Annual Meeting, each
share of Class A Common Stock is entitled to one vote, and each share of
Class B Common Stock is entitled to ten votes. The Class C Common Stock is not
entitled to vote on the matters submitted for vote at the Annual Meeting.

    Except with respect to the election of two of the directors, the Class A
Common Stock and the Class B Common Stock will vote as a single class in regards
to the matters submitted at the Annual Meeting. With respect to the election of
directors, the holders of Class A Common Stock are entitled by class vote,
exclusive of all other stockholders, to elect two Class A directors (the
"Class A Directors"). On March 26, 2001, there were outstanding and entitled to
vote 180,324,753 shares of Class A Common Stock and 8,073,635 shares of Class B
Common Stock.

    The presence at the Annual Meeting, in person or by proxy, of the holders of
a majority of the votes represented by the Class A Common Stock and the Class B
Common Stock issued and outstanding on March 26, 2001 will constitute a quorum
for the transaction of business at the Annual Meeting. For the separate vote of
the Class A Common Stock, a quorum will be the presence in person or by proxy of
the holders of a majority of the votes represented by the Class A Common Stock.
Votes withheld, abstentions and broker non-votes shall be counted for purposes
of determining the presence or absence of a quorum for the transaction of
business at the Annual Meeting.

    Stockholders who do not attend the Annual Meeting in person may submit
proxies by mail or over the Internet. Proxies in the enclosed form and proxies
properly submitted over the Internet, if received in time for voting and not
revoked, will be voted at the Annual Meeting in accordance with the

                                       1

instructions contained therein. If no instructions are indicated, the shares
represented by the proxy will be voted:

    - FOR the election of the Director nominees named herein;

    - FOR the amendment to the Company's Amended and Restated 1997 Stock Option
      Plan;

    - FOR the ratification of the appointment of Deloitte & Touche LLP as the
      Company's independent auditors for the current fiscal year; and

    - In accordance with the judgment of the proxy holders as to any other
      matter that may be properly brought before the Meeting or any adjournments
      thereof.

    Shares which abstain from voting on a particular matter, and shares held in
"street name" by brokers or nominees who indicate on their proxies that they do
not have discretionary authority to vote such shares as to a particular matter
("broker non-votes"), will not be counted as votes in favor of such matter, and
will also not be counted as votes cast or shares voting on such matter.
Accordingly, abstentions and broker non-votes will have no effect on the voting
for the election of directors, which requires the affirmative vote of a
plurality of the votes cast or shares voting on the matter. In addition,
abstentions and broker non-votes will have no effect on the voting on the
remaining matters to be voted on at the Annual Meeting, each of which requires
the affirmative vote of a majority of the votes cast or shares voting on the
matter.

    Stockholders may vote by any one of the following means:

    - by mail;

    - over the Internet; or

    - in person, at the Annual Meeting.

    To vote by mail, sign, date and complete the enclosed proxy card and return
it in the enclosed self-addressed envelope. No postage is necessary if the proxy
card is mailed in the United States. Instructions for voting over the Internet
can be found on your proxy card. If you hold your shares through a bank, broker
or other nominee, it will give you separate instructions for voting your shares.

REVOCABILITY OF PROXIES

    Any stockholder giving a proxy has the power to revoke it at any time before
it is exercised. The proxy may be revoked by filing an instrument of revocation
or a duly executed proxy bearing a later date with the Secretary of the Company,
at the principal executive offices of the Company, 116 Huntington Avenue,
Boston, Massachusetts 02116. A proxy submitted over the Internet may be revoked
and a new proxy may be submitted in its place in accordance with the
instructions set forth on the Internet voting website. Any proxy may also be
revoked by attending the Annual Meeting and voting in person. If not revoked,
the proxy will be voted at the Annual Meeting in accordance with the
stockholder's instructions indicated on the proxy card or, if submitted over the
Internet, as indicated on such submission.

SOLICITATION

    All costs of solicitation of proxies will be borne by the Company. In
addition to solicitations by mail, the Company's directors, officers and regular
employees, without additional remuneration, may solicit proxies by telephone,
telecopy and personal interviews. Brokers, banks, custodians and other
fiduciaries will be requested to forward proxy soliciting material to the
beneficial owners of stock held of record by such persons. The Company will
reimburse them for their reasonable out-of-pocket expenses incurred in
connection with the distribution of such proxy materials. In addition, the
Company may retain a professional solicitor to solicit proxies from banks,
brokers, nominees and intermediaries. If the Company retains a solicitor, it
expects to pay approximately $15,000 for any such services, plus reasonable
out-of-pocket expenses.

                                       2

SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

    The following sets forth certain information known to us as of February 28,
2001 with respect to the shares of Common Stock that are beneficially owned as
of such date by:

    - each director,

    - the Chief Executive Officer and the four other most highly compensated
      executive officers who were serving as executive officers on December 31,
      2000 (the "Named Executive Officers");

    - all directors and executive officers as a group; and

    - each person known by us to beneficially own more than 5% of our
      outstanding Common Stock.

    The number of shares of Common Stock beneficially owned by each person is
determined under rules promulgated by the Securities and Exchange Commission
(the "SEC"), and the information is not necessarily indicative of beneficial
ownership for any other purpose. Under these rules, beneficial ownership
includes any shares as to which the individual or entity has sole or shared
voting power or investment power and also any shares which the individual or
entity had the right to acquire within sixty days of February 28, 2001 through
the exercise of an option, conversion feature or similar right ("Presently
Exercisable Options"). All percentages are based on the shares of Common Stock
outstanding as of February 28, 2001. Except as noted below, each holder has sole
voting and investment power with respect to all shares of Common Stock listed as
owned by that holder.



                                                                                              PERCENT OF
                                       NUMBER OF    PERCENT OF   PERCENT OF    PERCENT OF    TOTAL VOTING
NAME AND ADDRESS OF BENEFICIAL OWNER     SHARES      CLASS A      CLASS B     COMMON STOCK      POWER
- ------------------------------------   ----------   ----------   ----------   ------------   ------------
                                                                              
DIRECTORS AND NAMED EXECUTIVE
  OFFICERS
Steven B. Dodge(1)...................   7,714,298      *            76.18         4.01           26.87
Thomas H. Stoner(2)..................   1,227,851      *            14.33        *                4.46
Alan L. Box(3).......................   1,018,550      *            --           *               *
Arnold L. Chavkin(4).................   5,931,924       2.03        --            3.11            1.40
Steven J. Moskowitz(5)...............     143,000      *            --           *               *
David W. Garrison(6).................      15,000      *            --           *               *
J. Michael Gearon, Jr.(7)............   2,993,268       1.66        --            1.57            1.15
Fred R. Lummis(8)....................   1,186,748      *            --           *               *
Douglas C. Wiest(9)..................     209,557      *            --           *               *
Maggie Wilderotter(10)...............      40,000      *            --           *               *
Joseph L. Winn(11)...................     598,413      *             3.21        *                1.13
All executive officers and directors
  as a group (15 persons)............  21,712,983       5.70        89.64        11.13           35.53

FIVE PERCENT STOCKHOLDERS
Massachusetts Financial Services
  Company(12)........................  22,371,469      12.42        --           11.74            8.57
Janus Capital Corporation(13)........  18,222,365      10.11        --            9.57            6.98
FMR Corp.(14)........................  15,416,691       8.56        --            8.09            5.91
American Century Investment
  Management(15).....................   9,638,100       5.35        --            5.06            3.69


- ---------

   * Less than 1%.

 (1) Mr. Dodge's address is 116 Huntington Avenue, Boston, Massachusetts 02116.
     Includes 10,030 shares of Class A Common Stock and 3,716,541 shares of
     Class B Common Stock owned by Mr. Dodge, an aggregate of 25,050 shares of
     Class A Common Stock and 33,915 shares of Class B Common Stock owned by
     three trusts for the benefit of Mr. Dodge's children, 2,000,000 shares of
     Class B Common Stock owned by a limited liability company, of which
     Mr. Dodge is

                                       3

     the sole member, 5,000 shares of Class A Common Stock owned by Mr. Dodge's
     wife and 5,000 shares of Class B Common Stock owned by a charitable
     foundation of which Mr. and Mrs. Dodge are trustees. Mr. Dodge's wife and a
     third party serve as co-trustees for the three trusts. Mr. Dodge disclaims
     beneficial ownership of all shares owned by such trusts, the charitable
     foundation and his wife. Does not include 170 shares of Class A Common
     Stock held by Thomas S. Dodge, an adult child of Mr. Dodge, with respect to
     which Mr. Dodge disclaims beneficial ownership. Includes Presently
     Exercisable Options to purchase an aggregate of 1,693,712 shares of
     Class B Common Stock and 200,000 shares of Class A Common Stock.

 (2) Mr. Stoner's address is 116 Huntington Avenue, Boston, Massachusetts 02116.
     Includes 31,311 shares of Class B Common Stock owned by his wife, an
     aggregate of 1,126,363 shares of Class B Common Stock and 2,500 shares of
     Class A Common Stock owned by trusts of which he and/or certain other
     persons are trustees, and 10,245 shares of Class A Common Stock to be
     issued upon conversion of convertible notes owned by a charitable
     foundation of which Mr. Stoner serves as an officer. Mr. Stoner disclaims
     beneficial ownership of 296,804 shares of Class B Common Stock and 2,500
     shares of Class A Common Stock owned by the charitable foundation and such
     trusts. Does not include 73,852 shares of Class A Common Stock and 28,127
     shares of Class B Common Stock owned by Mr. Stoner's adult children with
     respect to which Mr. Stoner disclaims beneficial ownership. Includes
     Presently Exercisable Options to purchase an aggregate of 57,432 shares of
     Class A Common Stock.

 (3) Includes 623,858 shares of Class A Common Stock owned by Mr. Box, 2,070
     shares of Class A Common Stock owned by two trusts for the benefit of
     Mr. Box's children and Presently Exercisable Options to purchase an
     aggregate of 392,623 shares of Class A Common Stock.

 (4) Mr. Chavkin, as an Executive Partner of J.P. Morgan Partners, LLC ("JPMP"),
     which indirectly controls J.P. Morgan Partners (BHCA), L.P. ("JPLP"), may
     be deemed to own beneficially shares held by JPLP and J.P. Morgan Partners
     (23A SBIC), LLC ("JPSBIC"), an affiliate of Mr. Chavkin. Includes 21,719
     shares of Class A Common Stock and 2,267,813 shares of Class C Common Stock
     owned by JPLP and 3,584,960 shares of Class A Common Stock owned by JPSBIC.
     Mr. Chavkin disclaims beneficial ownership of such shares. Includes
     Presently Exercisable Options to purchase an aggregate of 57,432 shares of
     Class A Common Stock. The address of JPMP and JPLP is 1221 Avenue of The
     Americas, New York, New York 10020.

 (5) Includes Presently Exercisable Options to purchase an aggregate of 140,000
     shares of Class A Common Stock.

 (6) Includes Presently Exercisable Options to purchase an aggregate of 15,000
     shares of Class A Common Stock.

 (7) Includes 723,743 shares of Class A Common Stock owned directly by
     Mr. Gearon and an aggregate of 2,068,854 shares of Class A Common Stock
     owned by limited partnerships that Mr. Gearon controls. Does not include
     100,000 shares of Class A Common Stock held by a trust for the benefit of
     Mr. Gearon's children, of which J. Michael Gearon, Sr. is the trustee.
     Mr. Gearon disclaims beneficial ownership in all shares owned by such
     trust. Includes Presently Exercisable Options to purchase an aggregate of
     200,671 shares of Class A Common Stock.

 (8) Includes 69,105 shares of Class A Common Stock owned by Mr. Lummis, an
     aggregate of 256,252 shares of Class A Common Stock owned by trusts of
     which he is trustee, 324,349 shares of Class A Common Stock owned by Summit
     Capital, Inc., an affiliate of Mr. Lummis by reason of Mr. Lummis's 50%
     ownership of its common stock. Mr. Lummis disclaims beneficial ownership of
     all shares owned by the trusts and Summit Capital, except to the extent of
     his pecuniary interest therein. Includes Presently Exercisable Options to
     purchase an aggregate of 537,042 shares of Class A Common Stock.

                                       4

 (9) Includes 3,556 shares of Class A Common Stock owned by Mr. Wiest. Includes
     Presently Exercisable Options to purchase an aggregate of 206,001 shares of
     Class A Common Stock.

 (10) Includes Presently Exercisable Options to purchase an aggregate of 40,000
      shares of Class A Common Stock.

 (11) Includes 2,000 shares of Class A Common Stock and 84,357 shares of
      Class B Common Stock owned individually by Mr. Winn and 100 shares of
      Class A Common Stock held for the benefit of his children. Includes
      Presently Exercisable Options to purchase an aggregate of 180,892 shares
      of Class B Common Stock and 331,064 shares of Class A Common Stock.

 (12) The address of Massachusetts Financial Services Company ("MFS") is 500
      Boylston Street, Boston, Massachusetts 02116. Based on MFS's Schedule 13G
      dated February 9, 2001, MFS has sole voting power over 22,015,089 shares
      of Class A Common Stock, and sole dispositive power over 22,371,469 shares
      of Class A Common Stock. The shares over which MFS has voting and
      dispositive power includes an aggregate of 375,551 shares of Class A
      Common Stock which MFS may acquire through the conversion of convertible
      notes.

 (13) The address of Janus Capital Corporation ("Janus") is 100 Fillmore Street,
      Denver, Colorado 80206. Based on Janus's Schedule 13G dated February 9,
      2001, Janus has sole voting and dispositive power over 18,222,365 shares
      of Class A Common Stock. The shares over which Janus has voting and
      dispositive power include 872,719 shares of Class A Common Stock that
      Janus may acquire through the conversion of convertible notes.

 (14) The address of FMR Corp. is 82 Devonshire Street, Boston, Massachusetts
      02109. Based on FMR's Schedule 13G dated February 13, 2001, FMR has sole
      voting power over 128,590 shares of Class A Common Stock and sole
      dispositive power over 15,416,691 shares of Class A Common Stock. FMR's
      Schedule 13G also indicates that Fidelity Management & Research Company
      ("Fidelity"), a wholly-owned subsidiary of FMR, is the beneficial owner of
      15,288,101 shares of Class A Common Stock. In addition, the Schedule 13G
      indicates that Fidelity Contrafund, an investment company advised by
      Fidelity, owns 11,224,400 shares of Class A Common Stock.

 (15) The address of American Century Management, Inc. ("ACIM") is 4500 Main
      Street, P.O. Box 418210, Kansas City, MO 64141. ACIM manages the
      investments of thirteen registered investment companies, including
      American Century Mutual Funds, Inc. ("ACMF"). Based on ACIM's
      Schedule 13G filed on February 13, 2001, ACIM has sole voting and
      dispositive power over 9,638,100 shares of Class A Common Stock, including
      9,535,000 shares held by ACMF.

                                       5

                                   PROPOSAL 1
                             ELECTION OF DIRECTORS

    The Board of Directors currently consists of eight directors. The Board of
Directors has nominated for election as directors at the Annual Meeting the
eight incumbent directors listed below. Persons elected at the meeting will hold
office until the 2002 Annual Meeting or until their successors are elected and
qualified, subject to earlier retirement, resignation or removal. If any of the
above nominees become unavailable to serve, the shares represented by proxies
will be voted for the election of such other person as may be recommended by the
Board of Directors or management. Unless otherwise instructed, proxies received
by the Company will be voted FOR the nominees listed below.

REQUIRED VOTE

    Except for the election of the Class A Directors, a plurality of the votes
properly cast by or on behalf of the holders of Class A Common Stock and
Class B Common Stock at the Annual Meeting, voting as a single class, is
required for the election of directors. For the election of the Class A
Directors, votes properly cast by or on behalf of the holders of a plurality of
Class A Common Stock at the Annual Meeting, voting as a separate class, is
required.

    Mr. Lummis and Ms. Wilderotter have been nominated as the Class A Directors.

    THE BOARD OF DIRECTORS RECOMMENDS THAT THE STOCKHOLDERS VOTE FOR THE
ELECTION OF EACH OF THE NOMINEES LISTED BELOW TO SERVE AS DIRECTORS OF THE
COMPANY UNTIL THE NEXT ANNUAL MEETING OR UNTIL THEIR SUCCESSORS ARE ELECTED AND
QUALIFIED.

    Set forth below are the name and age of each director, his or her principal
occupation and business experience during the past five years and the names of
other publicly traded companies of which he or she serves as a director as of
February 28, 2001.



NOMINEE                  PRINCIPAL OCCUPATIONS AND BUSINESS EXPERIENCE DURING THE PAST FIVE YEARS
- -------                  ------------------------------------------------------------------------
                      
Steven B. Dodge          Mr. Dodge has served as our Chairman of the Board, President and Chief
Age 55                   Executive Officer since our separation from American Radio Systems
                         ("American Radio") in June 1998 (the "ATC Separation"). Mr. Dodge has
                         been a member of the Executive Committee since November 1997. Mr. Dodge
                         was the Chairman of the Board of Directors, President and Chief
                         Executive Officer of American Radio from its founding in November 1993
                         until the ATC Separation. In 1988, Mr. Dodge founded Atlantic Radio, one
                         of the predecessor entities of American Radio. Mr. Dodge currently
                         serves as a director of Citizens Financial Group, Inc., Nextel
                         Partners, Inc., Sothebys Holdings, Inc. and TD Waterhouse Group, Inc.

Alan L. Box              Mr. Box has served as an Executive Vice President since March 1998 and
Age 49                   has been a director since our organization. Mr. Box served as our Chief
                         Operating Officer from June 1997 to March 1998, at which time he assumed
                         his present role as the Executive Vice President responsible for our
                         satellite and fiber network access services business. Mr. Box was an
                         Executive Vice President and a director of American Radio from
                         April 1997, when EZ Communications ("EZ") merged into American Radio,
                         until the ATC Separation. Prior to April 1997, Mr. Box had been the
                         Chief Executive Officer of EZ, a company he joined in 1974.


                                       6




NOMINEE                  PRINCIPAL OCCUPATIONS AND BUSINESS EXPERIENCE DURING THE PAST FIVE YEARS
- -------                  ------------------------------------------------------------------------
                      
Arnold L. Chavkin        Mr. Chavkin has been a member of the Executive Committee and the
Age 49                   Compensation Committee since November 1997. Mr. Chavkin is currently a
                         member of the Audit Committee. Mr. Chavkin served on the Audit Committee
                         since the ATC Separation until May 2000, and was reappointed in March
                         2001. Mr. Chavkin is an Executive Partner of JPMP, the investment
                         adviser to JPLP and JPSBIC, stockholders of American Tower. He is also
                         an Executive Vice President of JPMP Capital Corp., a subsidiary of
                         J.P. Morgan Chase & Co., which is the general partner of the general
                         partner of JPLP. In addition, Mr. Chavkin has been the President of
                         Chemical Investments, Inc. since 1991. Mr. Chavkin serves as a director
                         of Better Minerals & Aggregates Co., Carrizo Oil & Gas Inc., Crown Media
                         Holdings, Inc., R&B Falcon Corp. and Triton PCS Holdings Inc.

David W. Garrison        Mr. Garrison is the Chairman and Chief Executive Officer of Verestar,
Age 45                   one of our wholly owned subsidiaries, and has been a director since
                         September 2000. From February 1995 to July 1998, Mr. Garrison served as
                         Chairman, Chief Executive Officer, Chief Operating Officer and President
                         of NETCOM OnLine Communications Services, Inc., a pioneer independent
                         provider of internet services in four countries. Prior to that, Mr.
                         Garrison was President of Skytel Communications, Inc., a leading
                         provider of wireless mobile data services, and Chairman and Chief
                         Executive Officer of Dial Page, Inc., a regional paging carrier based in
                         the Southeast United States, which became part of Nextel Communications,
                         Inc. Mr. Garrison currently serves as a director of Ameritrade Holding
                         Corporation.

J. Michael Gearon, Jr.   Mr. Gearon is President of American Tower International and has been a
Age 36                   director since our acquisition of Gearon Communications in January 1998.
                         In addition, he has served as an Executive Vice President since January
                         1998. Prior to joining us, Mr. Gearon had been the founder and Chief
                         Executive Officer of Gearon Communications since September 1991, which
                         he developed into one of the fastest growing private companies in the
                         United States.

Fred R. Lummis           Mr. Lummis has been a member of the Audit Committee since our merger
Age 47                   with American Tower Corporation ("Old ATC"), an unaffiliated company, in
                         June 1998. Mr. Lummis was the Chairman, Chief Executive Officer and
                         President of Old ATC from September 1994 through June 1998. From June
                         1998 until early 2000, Mr. Lummis also served as the Chairman, President
                         and Chief Executive Officer of Advantage Outdoor Company, L.P. Mr.
                         Lummis has been the President of Summit Capital, Inc., a private
                         investment firm and a substantial stockholder of Old ATC, since June
                         1990.


                                       7




NOMINEE                  PRINCIPAL OCCUPATIONS AND BUSINESS EXPERIENCE DURING THE PAST FIVE YEARS
- -------                  ------------------------------------------------------------------------
                      
Thomas H. Stoner         Mr. Stoner has been the Chairman of the Executive Committee and the
Age 66                   Compensation Committee since November 1997. Mr. Stoner was the Chairman
                         of the Executive Committee and the Compensation Committee of American
                         Radio from its founding until the ATC Separation. In 1965, Mr. Stoner
                         founded Stoner Broadcasting Systems, Inc., one of the predecessors of
                         American Radio.

Maggie Wilderotter       Ms. Wilderotter has been a director since August 1998. Ms. Wilderotter
Age 46                   has been a member of the Audit Committee since March 2001 and a member
                         of the Compensation Committee since November 1998. Ms. Wilderotter is
                         the President and Chief Executive Officer of Wink Communications, Inc.
                         ("Wink"), a California company that develops technology for adding
                         simple interactivity and graphics to mass-market consumer electronic
                         products. Before joining Wink in 1997, Ms. Wilderotter was the Executive
                         Vice President of National Operations for AT&T Wireless Services, Inc.,
                         and Chief Executive Officer of AT&T's Aviation Communications Division.
                         Ms. Wilderotter has also served as Senior Vice President of McCaw
                         Cellular Communications, Inc. and Regional President of its California,
                         Arizona, New Mexico, Nevada and Hawaii Region. Ms. Wilderotter serves as
                         a director of Airborne, Inc., Electric Lightwave, Inc., Gaylord
                         Entertainment Company, The McClatchy Corporation and Wink
                         Communications, Inc.


BOARD AND COMMITTEE MEETINGS

    During the fiscal year ended December 31, 2000, the Board of Directors held
four regular meetings, one special meeting by telephone and took actions by
written consent. Each of the current directors who was then in office attended
at least 75% of the aggregate number of meetings of the Board of Directors and
all committees thereof on which such director served. The committees of the
Board of Directors consist of an Audit Committee, a Compensation Committee and
an Executive Committee. During the fiscal year ended December 31, 2000, the
Compensation Committee held two meetings, the Executive Committee held two
meetings and the Audit Committee held six meetings. The Company does not have a
nominating committee.

    AUDIT COMMITTEE.  The Audit Committee consists of Messrs. Lummis (Chairman)
and Chavkin and Ms. Wilderotter (who was elected to the Audit Committee on
March 15, 2001). The Audit Committee assists the Board of Directors in
fulfilling its responsibility to oversee management's conduct of the Company's
financial reporting process. This includes the selection of the Company's
outside auditors and the review of the financial reports and other financial
information provided by the Company to any governmental or regulatory body, the
public or other users, its systems of internal accounting and financial
controls, and the annual independent audit of its financial statements. The
Board of Directors has adopted a charter for the Audit Committee, which is
attached as Appendix I to this proxy statement.

    New audit committee rules of the New York Stock Exchange will become
effective on June 14, 2001. These rules require listed companies to have an
audit committee composed of a minimum of three members who meet specified
standards for independence and financial background. As part of the definition
of independence, these new rules contain a statement that a person who was an
employee of the company cannot serve on the audit committee until three years
have elapsed since such employment terminated, unless the Board of Directors
determines that the person's membership on the audit committee is in the best
interests of the company and its stockholders. According to the interpretations
of the New York Stock Exchange, Fred Lummis' past employment at American Tower
Corporation, an unaffiliated company that the Company acquired on June 8, 1998,
will be treated as

                                       8

employment by the Company for the purposes of this rule, even though Mr. Lummis
has never been an employee of the Company. In accordance with Section 303.02(D)
of the New York Stock Exchange Listed Company Manual, the Board of Directors
determined that it would be in the best interests of the Company and its
stockholders for Fred Lummis to continue to serve on the Audit Committee. The
Board of Directors made this determination based on the following factors:
(i) Mr. Lummis' contributions as an Audit Committee member since June 1998,
(ii) his financial sophistication, (iii) Mr. Lummis having never been an
employee of the Company and three years having elapsed on June 8, 2001 since
Mr. Lummis was employed by the unaffiliated American Tower Corporation, and
(iv) the Board of Directors' determination that he is otherwise independent from
management. In re-appointing Mr. Chavkin to the Audit Committee, the Board of
Directors determined that Mr. Chavkin's position as an Executive Partner of
JPMP, which is an affiliate of JPLP and JPSBIC, stockholders of the Company, and
The Chase Manhattan Bank, a lender under our credit facilities, does not
interfere with the exercise of his independent judgement. In appointing
Ms. Wilderotter to the Audit Committee on March 15, 2001, the Board of Directors
determined that she has no relationships with the Company that would interfere
with the exercise of her independent judgement.

    COMPENSATION COMMITTEE.  The Compensation Committee currently consists of
Messrs. Stoner (Chairman) and Chavkin and Ms. Wilderotter. The Compensation
Committee provides recommendations to the Board of Directors regarding
compensation strategy and programs and administers the Stock Option Plan,
including the grant of stock options thereunder. The Compensation Committee is
also responsible for establishing and modifying the compensation, including
incentive compensation, of all corporate officers, recommending adoptions of,
and amendment to, all stock option and other employee benefit plans and
arrangements, and the engagement of, terms of any employment agreements and
arrangements with, and termination of, all corporate officers.

    EXECUTIVE COMMITTEE.  The Executive Committee currently consists of
Messrs. Stoner (Chairman), Dodge and Chavkin. Between meetings of the Board of
Directors, the Executive Committee exercises all the powers of the Board of
Directors in the management and direction of the business and affairs of the
Company, except as provided otherwise by law, resolutions of the Board of
Directors or the Restated Certificate of Incorporation or By-laws.

                                       9

                             AUDIT COMMITTEE REPORT

    The Audit Committee has reviewed the Company's audited financial statements
for the fiscal year ended December 31, 2000 and discussed these financial
statements with the Company's management. The Audit Committee also reviewed and
discussed the audited financial statements and the matters required by Statement
on Auditing Standards No. 61, as amended, (Communication with Audit Committees)
with Deloitte & Touche LLP, the Company's independent auditors.

    The Company's independent auditors also provided the Audit Committee with
the written disclosures and the letter required by Independence Standards Board
Standard No. 1 (Independence Discussions with Audit Committees). In addition,
the Audit Committee discussed with the independent auditors their independence
from the Company. The Audit Committee also considered whether the independent
auditors' provision of other, non-audit related services to the Company is
compatible with maintaining such auditors' independence. The fees paid to our
independent auditors for the year ended December 31, 2000 were as follows:

AUDIT FEES

    Deloitte & Touche LLP billed the Company an aggregate of $542,000 (including
expenses) in fees for professional services rendered in connection with the
audit of the Company's financial statements for the year ended December 31, 2000
and the reviews of the financial statements included in each of the Company's
Quarterly Reports on Form 10-Q during the fiscal year ended December 31, 2000.

FINANCIAL INFORMATION SYSTEMS DESIGN AND IMPLEMENTATION FEES

    During the fiscal year ended December 31, 2000, Deloitte & Touche LLP did
not perform or receive any fees for any professional services for the Company
and its affiliates in connection with financial information systems design or
implementation, the operation of the Company's information system or the
management of its local area network.

ALL OTHER FEES

    Deloitte & Touche LLP billed the Company an aggregate of $2.6 million in
fees and expenses for other services rendered to the Company and its affiliates
for the fiscal year ended December 31, 2000.

    Based on its discussions with management and the independent auditors, and
its review of the representations and information provided by management and the
independent auditors, the Audit Committee recommended to the Company's Board of
Directors that the audited financial statements be included in the Company's
Annual Report on Form 10-K for the year ended December 31, 2000.

    By the Audit Committee of the Board of Directors of American Tower
Corporation.


                                            
                                               AUDIT COMMITTEE
                                               Fred R. Lummis
                                               Arnold L. Chavkin


                                       10

      COMPENSATION AND OTHER INFORMATION CONCERNING DIRECTORS AND OFFICERS

DIRECTOR COMPENSATION

    We granted our four nonemployee directors options to purchase an aggregate
of 60,000 shares of Class A Common Stock during the fiscal year ended
December 31, 2000. In September 2000, we granted each of Messrs. Chavkin, Lummis
and Stoner and Ms. Wilderotter an option to purchase 15,000 shares of Class A
Common Stock. All of the options granted to the nonemployee directors are
immediately exercisable for 100% of the underlying shares and expire at the end
of ten years. The four nonemployee directors also receive $2,500 for attending
each board meeting, $1,000 for serving on each committee on which he or she
serves, and $3,000 for serving on each committee on which he or she serves as
chairperson.

EXECUTIVE COMPENSATION

    The following table provides certain information concerning compensation
earned by each of the Named Executive Officers for the fiscal years ended
December 31, 1998, 1999 and 2000:

                           SUMMARY COMPENSATION TABLE



                                                                                    LONG-TERM
                                               ANNUAL COMPENSATION                 COMPENSATION
                                  ----------------------------------------------   ------------
                                                                                    SECURITIES
                                                                    OTHER ANNUAL    UNDERLYING       ALL OTHER
  NAME AND PRINCIPAL POSITION       YEAR     SALARY(A)    BONUS     COMPENSATION     OPTIONS      COMPENSATION(B)
  ---------------------------     --------   ---------   --------   ------------   ------------   ---------------
                                                                                
Steven B. Dodge ................  2000       $229,757         --             --        300,000        $   774
  Chairman of the Board,          1999        412,363         --             --        300,000          6,736
  President and Chief Executive   1998(c)     370,349         --             --      3,300,000          5,946
  Officer

Douglas C. Wiest ...............  2000        302,354         --             --        125,000         42,403
  Chief Operating Officer         1999        318,001         --             --         60,000          8,400
                                  1998        211,007         --             --        365,001          4,576

Joseph L. Winn .................  2000        302,394         --             --        100,000         10,062
  Treasurer and Chief Financial   1999        288,268         --             --         60,000         12,996
  Officer                         1998(c)     298,779                                  610,000         13,210

J. Michael Gearon, Jr. .........  2000        302,217         --             --        200,000            594
  Executive Vice President and    1999        212,625         --             --        100,000            476
  President of American Tower     1998        176,135                                  334,451            346
  International

Steven J. Moskowitz ............  2000        282,669    $50,000             --        100,000          5,450
  Executive Vice President--      1999        202,375         --             --             --            756
  Marketing and Vice President    1998        202,503     46,989             --             --            462
  and General Manager Northeast
  Region


- ---------

(a) Includes employer's 401(k) plan contributions.

(b) Includes group term life insurance, automobile expense and parking expenses
    paid by employer, except for Mr. Gearon, in which case it includes group
    term life insurance only.

(c) Represents compensation paid by both American Radio and us for 1998.

OPTION GRANTS IN 2000

    The following table sets forth certain information relating to 2000 option
grants pursuant to the 1997 Stock Option Plan, as amended and restated ("the
Stock Option Plan"), issued to the individuals named in the Summary Compensation
Table above.

                                       11

                       OPTION GRANTS IN LAST FISCAL YEAR



                                                     INDIVIDUAL GRANTS
                                    ----------------------------------------------------   POTENTIAL REALIZABLE VALUE AT
                                    NUMBER OF      PERCENT OF                                 ASSUMED ANNUAL RATES OF
                                    SECURITIES   TOTAL OPTIONS                              STOCK PRICE APPRECIATION FOR
                                    UNDERLYING     GRANTED TO     EXERCISE                         OPTION TERM(C)
                                     OPTIONS      EMPLOYEES IN    PRICE PER   EXPIRATION   ------------------------------
               NAME                  GRANTED     FISCAL 2000(A)   SHARE(B)       DATE           5%              10%
               ----                 ----------   --------------   ---------   ----------   -------------   --------------
                                                                                         
Steven B. Dodge...................   300,000          4.23%        $30.625      9/21/10     $5,777,969      $14,642,508
Douglas C. Wiest..................   125,000          1.76          30.625      9/21/10      2,407,487        6,101,045
Joseph L. Winn....................   100,000          1.41          30.625      9/21/10      1,925,989        4,880,836
J. Michael Gearon, Jr.............   200,000          2.82          30.625      9/21/10      3,851,979        9,761,672
Steven J. Moskowitz...............   100,000          1.41          30.625      9/21/10      1,925,989        4,880,836


- ---------

(a) Based on options to purchase an aggregate of 7,092,350 shares granted to our
    employees and directors pursuant to our Stock Option Plan during the year
    ended December 31, 2000.

(b) The exercise price per share of each option was equal to the fair market
    value per share of the underlying stock as valued by the Board of Directors
    on the date of grant.

(c) The potential realizable value is calculated based on the term of option at
    the time of grant. Stock price appreciation of 5% and 10% is assumed
    pursuant to rules promulgated by the Securities and Exchange Commission and
    does not represent our prediction of stock price performance. The potential
    realizable values at 5% and 10% appreciation are calculated by assuming that
    the exercise price on the date of grant appreciates at the indicated rate
    for the entire term of the option and that the option is exercised at the
    exercise price and sold on the last day of its term at the appreciated
    price.

AGGREGATED OPTION EXERCISES IN LAST FISCAL YEAR AND FISCAL YEAR-END OPTION
  VALUES

    The following table sets forth certain information regarding the unexercised
options granted pursuant to the Stock Option Plan (or outstanding with respect
to options granted under predecessor plans) to the individuals referred to in
the Summary Compensation Table above.

                  AGGREGATED OPTION VALUES IN LAST FISCAL YEAR
                       AND FISCAL YEAR-END OPTION VALUES



                                                                  NUMBER OF SECURITIES
                                                                 UNDERLYING UNEXERCISED         VALUE OF UNEXERCISED
                                                                       OPTIONS AT              IN-THE-MONEY OPTIONS AT
                                     SHARES                         DECEMBER 31, 2000           DECEMBER 31, 2000(A)
                                    ACQUIRED        VALUE      ---------------------------   ---------------------------
              NAME                 ON EXERCISE    REALIZED     EXERCISABLE   UNEXERCISABLE   EXERCISABLE   UNEXERCISABLE
              ----                 -----------   -----------   -----------   -------------   -----------   -------------
                                                                                         
Steven B. Dodge(b)...............    665,390     $16,236,879    2,348,712      1,787,155     $59,332,791    $35,299,930
Douglas C. Wiest.................     --             --           274,251        275,750       5,205,462      4,280,187
Joseph L. Winn(c)................      3,700         104,802      615,956        376,753      14,520,359      6,855,240
J. Michael Gearon, Jr............     --             --           290,671        343,780       5,271,691      4,829,027
Steven J. Moskowitz..............     --             --           199,000        211,000       3,847,520      3,269,180


- ---------

(a) Based on the closing price of the Class A common stock on the New York Stock
    Exchange on December 29, 2000 of $37.875 per share.

(b) Represents options to purchase shares of Class B common stock exercised on
    June 22, 2000.

(c) Represents options to purchase shares of Class B common stock exercised on
    December 4, 2000.

COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION

    The Chase Manhattan Bank, or Chase, an entity related to JPMP, JPLP and
JPSBIC, affiliates of Mr. Chavkin, has been and is a lender under our credit
facilities. See "Certain Relationships and Related Transactions".

                                       12

COMPENSATION COMMITTEE REPORT

    The Compensation Committee has the responsibility to review, recommend and
approve the Company's compensation policies and programs, including all
compensation for the Chief Executive Officer and the other executive officers.
The Compensation Committee consists entirely of directors who are both
"non-employee" directors within the meaning of Rule 16b-3 under Section 16 of
the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and
"outside" directors within the meaning of Section 162(m) of the Internal Revenue
Code of 1986, as amended (the "Code"), and the regulations thereunder, so that
grants of options under the Stock Option Plan to executive officers are exempt
under Rule 16b-3 and eligible for the "performance-based" exception of
Section 162(m) of the Code. The Compensation Committee administers the Stock
Option Plan and in exercise of that function determines what grants of stock
options thereunder are to be made to the Chief Executive Officer and the other
executive officers.

    The compensation policies adopted and implemented by the Compensation
Committee, combining base salary and incentive compensation principally in the
form of long-term stock options with a four- or five-year vesting schedule, are
designed to achieve the operating and acquisition strategies and goals of the
Company. By placing a greater emphasis on the long-term incentive aspects of the
overall compensation program, it is hoped that financial incentives will be
provided to motivate those responsible for achieving those goals and, at the
same time, aligning the interests of those persons with the stockholders. The
purpose of the Stock Option Plan is to encourage key employees, directors and
advisors who render services of special importance to, and who have contributed
or are expected to contribute materially to the success of, the Company to
continue their association by providing favorable opportunities for them to
participate in stock ownership and in future growth. The Compensation Committee
made stock option grants to Messrs. Dodge, Gearon, Moskowitz, Wiest, and Winn in
2000.

    The Compensation Committee determined the salary levels of the executive
officers, including the Chief Executive Officer, for 2000. The compensation
policies implemented by the Compensation Committee, which combine base salary
and incentive compensation in the form of long-term stock options, are designed
to achieve the operating and acquisition strategies and goals of the Company. In
particular, in determining salary levels and awards of long-term stock options
for 2000, the Compensation Committee took into account the past or expected
future contributions of each executive officer to the Company's strategic goals,
especially the efforts of each such officer in connection with strategic
acquisitions, construction activities and sales and marketing activities.

    The compensation of Steven B. Dodge, the Chairman of the Board of Directors,
President and Chief Executive Officer, is determined by the Compensation
Committee based upon the same factors as those employed by the Compensation
Committee for executive officers generally. In addition, the Compensation
Committee weighs Mr. Dodge's leadership, industry prominence and overall Company
performance as important criteria upon which his compensation is based.
Mr. Dodge voluntarily reduced his compensation for 2000. The Compensation
Committee believes that Mr. Dodge's 2000 compensation, as so reduced, was
significantly below market rates given his historic and anticipated
contributions to the Company and its performance in 2000.

    Section 162(m) of the Code generally disallows an income tax deduction to
public companies for compensation in excess of $1,000,000 paid in any year to
the chief executive officer or any of the four most highly compensated other
executive officers. There is an exception to this limitation for qualified
"performance-based" compensation within the meaning of Section 162(m). Although
the Compensation Committee has not adopted any specific rules with respect to
this issue, its general policy, subject to all then prevailing relevant
circumstances, is to attempt to structure American Tower option grants to
maximize deductions for federal income tax purposes.


                                               
                                                  COMPENSATION COMMITTEE
                                                  Thomas H. Stoner, Chairman
                                                  Arnold L. Chavkin
                                                  Maggie Wilderotter


                                       13

EMPLOYMENT AGREEMENTS AND SEVERANCE AND CHANGE OF CONTROL ARRANGEMENTS

    J. Michael Gearon, Jr. and Douglas C. Wiest are the only executive officers
who have employment agreements. Mr. Gearon entered into his employment agreement
in connection with our acquisition of Gearon Communications. That employment
agreement is for an initial term that ended December 31, 2000 and is renewable
thereafter for successive one-year periods. It provides that Mr. Gearon shall
receive an annual minimum base salary of $200,000 and shall be eligible to
participate in our Stock Option Plan and other benefits. Mr. Wiest's employment
agreement provides for a lump sum cash payment of $350,000, or 1.5 times his
salary, if Mr. Wiest's employment is terminated (except for cause) within five
years of the date of the agreement (April 13, 1998). It also provides that under
certain circumstances, if we are sold within such five-year period, Mr. Wiest
would be entitled to accelerated vesting of any options he held at the time.

                 CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

    Chase is a lender in our credit facilities and had a participation ranging
from 3.14% to 6.67% during 2000. Chase is an affiliate of JPMP, JPLP and JPSBIC.
JPLP and JPSBIC are stockholders of our company. Mr. Chavkin, one of our
directors, is a general partner of JPMP. The aggregate principal amount
outstanding under our credit facilities was $1.35 billion as of December 31,
2000. Chase's participation in our credit facilities at December 31, 2000 was
3.14%. Chase's share of interest and fees earned from us pursuant to our various
credit arrangements during 2000 was approximately $3.2 million.

    We are in the process of negotiating an arrangement with Mr. Gearon pursuant
to which an entity he controls may purchase a significant equity interest in
each of two of our international subsidiaries. One of these subsidiaries
currently operates our Mexican operations. The other subsidiary is expected to
operate in selected countries in which we do not currently have operations. It
is expected that the entity controlled by Mr. Gearon will pay between
$20.0 million and $25.0 million for those interests, a substantial portion of
which will be represented by promissory notes of such entity.

    James S. Eisenstein, our Executive Vice President, Corporate Development,
received a $1.0 million demand loan in August 1998 and repaid approximately
$700,000 in 1999. As of December 31, 2000, the outstanding principal amount of
the loan was $300,000, which was assigned by Mr. Eisenstein to a third party.

    Bradley E. Singer, our Executive Vice President, Strategy, received a
$180,000 demand loan in 2001. As of March 22, 2001, the outstanding principal
amount of the loan was $180,000.

    Mr. Wiest received a $700,000 demand loan in March 1999 and an additional
advance in December 1999 of $100,000. As of December 31, 2000, the outstanding
principal amount of the loan was $700,000.

                                       14

                               PERFORMANCE GRAPH

    The following graph compares the percentage change in the Class A Common
Stock to (1) the cumulative total return of the Russell Midcap Index (Broad
Market index) and (2) the group of companies selected as the Company's peers in
the communications site industry at the current time (the "Peer Group"),
assuming an investment of $100 on June 5, 1998. The Peer Group includes Crown
Castle International Corp., Spectrasite Holdings Inc. (formerly Westower
Corporation), LCC International, Inc., Pinnacle Holdings Inc. and SBA
Communications Corporation. Pinnacle Holdings Inc. and SBA Communications
Corporation became public companies in 1999.

    On February 27, 1998, the Class A Common Stock commenced trading on a "when
issued" basis on the inter-dealer bulletin board of the over-the-counter market.
The Class A Common Stock commenced trading on the NYSE on June 5, 1998 (the day
after the ATC Separation). The following graph presents the trading information
commencing on June 5, 1998 and does not present the trading information for such
"when issued" market. The cumulative return assumes reinvestment of all
dividends. The performance of the Company's Class A Common Stock reflected below
is not necessarily indicative of future performance.

                     COMPARISON OF CUMULATIVE TOTAL RETURN
                      BETWEEN AMERICAN TOWER CORPORATION,
                   RUSSELL MIDCAP INDEX, AND PEER GROUP INDEX

EDGAR REPRESENTATION OF DATA POINTS USED IN PRINTED GRAPHIC



                            6/5/1998  12/31/98  12/31/99  12/29/00
                                              
American Tower Corporation   $100.00   $129.23   $133.61   $165.57
RUSSELL Midcap Index         $100.00   $101.37   $119.85   $129.74
Peer Group                   $100.00    $43.70    $65.99    $50.09




                                                                CUMULATIVE TOTAL RETURN
                                                       -----------------------------------------
                                                       6/5/1998   12/31/98   12/31/99   12/29/00
                                                       --------   --------   --------   --------
                                                                            
American Tower Corporation...........................   100.00     129.23     133.61     165.57
Russell Midcap Index.................................   100.00     101.37     119.85     129.74
Peer Group...........................................   100.00      43.70      65.99      50.09


                                       15

                                   PROPOSAL 2

              EVERGREEN AMENDMENT TO PROVIDE FOR ANNUAL INCREASES
                 IN THE NUMBER OF SHARES RESERVED FOR ISSUANCE
                     UNDER THE COMPANY'S STOCK OPTION PLAN

    On March 15, 2001, the Board of Directors adopted resolutions, subject to
stockholder approval, to amend the Stock Option Plan to provide for automatic
annual increases in the number of shares authorized for issuance thereunder (the
"Evergreen Amendment"). The Board of Directors believes that equity interests
have been and will continue to be a significant factor in the ability to
attract, retain and motivate the officers and other key employees, directors and
consultants that are critical to the Company's long-term success. The rapid
growth of the Company has increased its need to grant employee stock options in
order to recruit and retain an increasing number of employees and corporate
officers.

    The purpose of the Evergreen Amendment is to maintain the size of the Stock
Option Plan so that the total number of shares authorized for issuance
thereunder, including all past and future issuances, equals 12% of the Company's
outstanding Common Stock on a modified fully-diluted share basis, as described
below ("FDS"). Currently, the total number of shares authorized for issuance
under the Stock Option Plan is 24,000,000 shares. As of February 1, 2001, this
number consists of approximately 20,600,000 shares authorized for issuance
pursuant to options that have already been granted under the Stock Option Plan,
with the remaining approximately 3,400,000 shares available for future option
grants. This total number of 24,000,000 authorized shares equals about 10.7% of
the FDS as of February 1, 2001.

    The Board of Directors believes that the optimum size of the Stock Option
Plan to address the needs of the Company is 12% of FDS. In order to maintain the
size of the Stock Option Plan at this 12% of FDS level without incurring the
expense of periodically soliciting stockholder approvals of increases in the
number of authorized shares under the Stock Option Plan, the Board of Directors
recommends that the stockholders approve the Evergreen Amendment. Please note
that this Evergreen Amendment will not annually increase the shares available
for new grants under the Stock Option Plan to equal 12% of FDS. Rather, it will
increase the overall number of shares authorized for issuance for all past and
future option grants under the Stock Option Plan so that it equals 12% of FDS.

    Specifically, the Evergreen Amendment provides that each September 30,
commencing September 30, 2001, the size of the Stock Option Plan will increase
by the number of shares of Class A Common Stock necessary, if any, so that total
shares authorized under the Stock Option Plan, including all past and future
issuances, equals 12% of FDS, as determined on such September 30. However, the
Board of Directors may approve a lesser increase for any such September 30.

    Under the terms of the Evergreen Amendment, FDS does NOT include any of the
following:

       - shares of Common Stock that are outstanding as a result of the exercise
         of stock options granted under the Stock Option Plan or any other
         employee, director or consultant options that we may approve, other
         than options under any employee stock purchase plan and options assumed
         or issued by the Company in connection with mergers or acquisitions,
         including the merger of American Radio and CBS; and

       - shares of Common Stock reserved for issuance in respect of options
         under the Stock Option Plan, any other employee, director or consultant
         options that we may approve or options under any employee stock
         purchase plan, other than options assumed or issued by the Company in
         connection with mergers or acquisitions, including the merger of
         American Radio and CBS.

These exclusions from the definition of FDS have the effect of limiting the size
of the annual increases under the Evergreen Amendment compared to the increases
that would be obtained using a more

                                       16

conventional definition of fully-diluted shares. For example, FDS will increase
as the Company issues shares of its Common Stock to finance its expansion or to
acquire new businesses, but will not increase merely because options are granted
or authorized to purchase shares of Common Stock under the Stock Option Plan or
any other employee, director or consultant options that the Company may approve
in the future, including options under any employee stock purchase plan.

    Pursuant to the terms of the Evergreen Amendment, the annual increase to
occur on September 30, 2001 would be approximately 2,700,000 shares, as
calculated based on FDS on February 1, 2001. The actual increase will, of
course, depend on the actual FDS on September 30, 2001.

    As part of the Evergreen Amendment, the Board of Directors has also amended
the Stock Option Plan to provide that the maximum number of shares that may be
issued pursuant to options under the Stock Option Plan that are intended to
qualify as incentive stock options will be 50,000,000 shares.

    As of February 1, 2001, options for 19,490,133 shares Class A and Class B
Common Stock were outstanding under the Stock Option Plan at exercise prices
ranging from $3.66 to $48.88 per share. As of that date, approximately 3,400,000
shares of Class A Common Stock were available for future grants. On March 26,
2001, the closing price per share of the Company's Class A Common Stock on the
NYSE was $20.25 per share.

    THE FOREGOING IS A SUMMARY OF THE EVERGREEN AMENDMENT. THE ACTUAL TEXT OF
THE AMENDMENT IS SET FORTH IN APPENDIX II TO THE PROXY STATEMENT, AND QUALIFIES
THIS SUMMARY IN ITS ENTIRETY.

REQUIRED VOTE

    A majority of the votes properly cast by or on behalf of the holders of
Class A and Class B Common Stock at the Annual Meeting, voting as a single
class, is required to approve the amendment of the Stock Option Plan to increase
the number of shares of Common Stock issuable thereunder as described above.

    THE BOARD OF DIRECTORS RECOMMENDS THAT THE STOCKHOLDERS VOTE FOR THE
APPROVAL OF THE EVERGREEN AMENDMENT TO THE STOCK OPTION PLAN.

                                       17

SUMMARY OF THE STOCK OPTION PLAN

    The following summary of the material features of the Stock Option Plan is
qualified in its entirety by reference to the full text of the Stock Option
Plan, which has been filed with the SEC and will be made available upon request.

    PURPOSE, PARTICIPANTS, EFFECTIVE DATE AND DURATION.  The Company instituted
the Stock Option Plan effective November 5, 1997 and amended and restated it on
April 27, 1998. The purpose of the Stock Option Plan is to encourage key
employees, directors and consultants of the Company and its Subsidiaries (a
Subsidiary is a corporation or other business organization the voting power or
equity interests of which are at least 50% owned by the Company, directly or
indirectly), who render services of special importance to the management,
operation or development of the Company or a Subsidiary, and who have
contributed or may be expected to contribute materially to the success of, the
Company or a Subsidiary (the "Participants"), to continue their association with
the Company and its Subsidiaries by providing favorable opportunities for them
to participate in the ownership of the Company and in its future growth through
the granting of options to acquire shares of the Class A Common Stock. As of
February 1, 2001, approximately 3,300 employees and four non-employee directors
were eligible to participate in the Stock Option Plan. The grant of options
under the Stock Option Plan is discretionary, and the Company cannot now
determine the number of options to be granted in the future to any particular
person or group.

    The Stock Option Plan will terminate on November 15, 2007, unless earlier
terminated by the Board of Directors. Termination of the Stock Option Plan will
not affect awards made prior to termination, but awards may not be made after
termination.

    SHARES SUBJECT TO THE STOCK OPTION PLAN.  The Stock Option Plan currently
provides that options may be granted to purchase shares of Class A Common Stock.
However, the Stock Option Plan currently limits the number of shares of Common
Stock for which options may be granted to an aggregate of 24,000,000 shares. The
Board of Directors recently approved, subject to stockholder approval, the
Evergreen Amendment to the Stock Option Plan providing for annual increases in
the shares authorized under the Stock Option Plan. Approval of this Evergreen
Amendment by stockholders is the subject of this Proposal 2 of this proxy
statement. These shares may be authorized and unissued shares or treasury
shares. The Stock Option Plan was amended in 1998 in connection with the Old ATC
merger as a result of which no options may now be granted to purchase Class B
Common Stock. In the event of any change in the number or kind of Class A and
Class B Common Stock outstanding pursuant to a reorganization, subdivision,
consolidation, recapitalization, exchange of shares, stock dividend or split or
combination of shares, appropriate adjustments will be made (1) to the number of
shares subject to outstanding options, (2) in the exercise price per share of
outstanding options, and (3) in the kind of shares which may be issued under the
Stock Option Plan. Shares will be deemed issued under the Stock Option Plan only
after full payment of the exercise price has been made. To the extent that an
award under the Stock Option Plan lapses or is forfeited, any shares subject to
such award will again become available for grant under the terms of the Stock
Option Plan subject, however, in the case of ISO's to any limitation under the
Code. The Stock Option Plan provides that American Tower may not grant options
to purchase more than 5,000,000 shares per year to any individual.

    ADMINISTRATION.  The Stock Option Plan is administered by the Compensation
Committee, which must consist solely of at least two directors who are both
"non-employee directors" within the meaning of Rule 16b-3 under the Exchange Act
and "outside directors" within the meaning of Section 162(m) of the Code.

    Subject to the terms of the Stock Option Plan, the Compensation Committee
has authority to: (1) select the persons to whom options shall be granted;
(2) determine the number or value and the

                                       18

terms and conditions of options granted to each such person, including the price
per share to be paid upon exercise of any option and the period within which
each such option may be exercised; and (3) interpret the Stock Option Plan and
prescribe rules and regulations for the administration thereof.

    STOCK OPTIONS.  With regard to each option, the Compensation Committee
determines the number of shares subject to the option, the exercise price of the
option, the manner and time of exercise of the option and whether the option is
intended to qualify as an incentive stock option, or ISO, within the meaning of
Section 422 of the Code. Options that are not intended to qualify as ISOs are
referred to as nonqualified stock options, or NSOs. ISOs may only be granted to
employees of the Company or a subsidiary as defined in Section 424(f) of the
Code. In the case of an ISO, and in the case of any option intended to qualify
as performance-based compensation under Section 162(m) of the Code, the exercise
price may not be less than the "fair market value" of the shares on the date the
option is granted. However, in the case of an employee who owns (or is
considered to own under Section 424(d) of the Code) stock possessing more than
10% percent of the total combined voting power of all classes of stock of the
Company or any of its parent or subsidiary corporations, the price at which
shares may be purchased pursuant to an ISO may not be less than 110% of the fair
market value of the class of Common Stock covered by the option on the date the
ISO is granted.

    The duration of the ISOs and NSOs granted under the Stock Option Plan are
required to be specified in a stock option agreement. However, no ISO may be
exercisable after the expiration of ten years after the date of grant and no NSO
may be exercisable after the expiration of ten years and one day after the date
of grant. In the case of any employee who owns (or is considered under
Section 424(d) of the Code as owning) stock possessing more than 10% of the
total combined voting power of all classes of stock of the Company or any of its
parent or subsidiary corporations, no ISO may be exercisable after the
expiration of five years from its date of grant. The Compensation Committee, in
its discretion, may provide that any option is exercisable during its entire
duration or during any lesser period of time.

    The option exercise price may be paid (1) in cash or a cash equivalent,
(2) through a so-called "cashless exercise" procedure, (3) to the extent
permitted by the Compensation Committee, in shares of Class A Common Stock owned
by the optionee or (4) to the extent permitted by the Compensation Committee, by
delivery of a recourse promissory note secured by, among other optionee assets,
the stock acquired upon exercise of the option. However, the optionee may not
make payment in shares that he acquired upon the earlier exercise of any ISO,
unless and until he has held the shares for at least two years after the date
the ISO was granted and at least one year after the date the ISO was exercised.

    AMENDMENTS TO THE STOCK OPTION PLAN.  The Board of Directors may modify,
revise or terminate the Stock Option Plan at any time and from time to time,
except that stockholder approval is required with respect to any amendment to
change the number of shares that may be issued under options in the aggregate or
to any one employee and to change the class of persons eligible to receive
options. Stockholder approval is also required for changes to the Stock Option
Plan that would adversely affect the qualification of the Stock Option Plan with
respect to the incentive stock option regulations and the protections of
Section 16(b) of the Exchange Act.

FEDERAL INCOME TAX CONSEQUENCES

    The following is a summary of the United States federal income tax
consequences that generally will arise with respect to options granted under the
Stock Option Plan and with respect to the sale of Common Stock acquired under
the Stock Option Plan. This summary is based on the federal tax laws in effect
of the date of this proxy statement. Changes to these laws could alter the tax
consequences described below.

                                       19

    INCENTIVE STOCK OPTIONS

    In general, an optionee will not recognize taxable income upon the grant or
exercise of an ISO. Instead, an optionee will recognize taxable income with
respect to an ISO only upon the sale of Common Stock acquired through the
exercise of the option ("ISO Stock"). The exercise of an ISO, however, may
subject the optionee to the alternative minimum tax.

    Generally, the tax consequences of selling ISO Stock will vary with the
length of time that the optionee has owned the ISO Stock at the time it is sold.
If the optionee sells ISO Stock after having owned it for at least two years
from the date the option was granted (the "Grant Date") and one year from the
date the option was exercised (the "Exercise Date"), then the optionee will
recognize long-term capital gain in an amount equal to the excess of the sale
price of the ISO Stock over the exercise price.

    If the optionee sells ISO Stock for more than the exercise price prior to
having owned it for at least two years from the Grant Date and one year from the
Exercise Date (a "Disqualifying Disposition"), then all or a portion of the gain
recognized by the optionee will be ordinary compensation income and the
remaining gain, if any, will be a capital gain. This capital gain will be a
long-term capital gain if the optionee has held the ISO Stock for more than one
year prior to the date of sale.

    If an optionee sells ISO Stock for less than the exercise price, then the
optionee will recognize capital loss in an amount equal to the excess of the
exercise price over the sale price of the ISO Stock. This capital loss will be a
long-term capital loss if the optionee has held the ISO Stock for more than one
year prior to the date of sale.

    NONSTATUTORY STOCK OPTIONS

    As in the case of an ISO, an optionee will not recognize taxable income upon
the grant of an NSO. Unlike the case of an ISO, however, an optionee who
exercises an NSO generally will recognize ordinary compensation income in an
amount equal to the excess of the fair market value of the Common Stock acquired
through the exercise of the option ("NSO Stock") on the Exercise Date over the
exercise price.

    With respect to any NSO Stock, an optionee will have a tax basis equal to
the exercise price plus any income recognized upon the exercise of the option.
Upon selling NSO Stock, an optionee generally will recognize capital gain or
loss in an amount equal to the difference between the sale price of the NSO
Stock and the optionee's tax basis in the NSO Stock. This capital gain or loss
will be a long-term gain or loss if the optionee has held the NSO Stock for more
than one year prior to the date of the sale.

    TAX CONSEQUENCES TO THE COMPANY

    The grant of an option under the Stock Option Plan generally will have no
tax consequences to the Company. Moreover, in general, neither the exercise of
an ISO nor the sale of any Common Stock acquired under the Stock Option Plan
will have any tax consequences to the Company. The Company generally will be
entitled to a business-expense deduction, however, with respect to any ordinary
compensation income recognized by an optionee under the Stock Option Plan,
including in connection with the exercise of an NSO or a Disqualifying
Disposition. Any such deduction will be subject to the limitations of
Section 162(m) of the Code.

                                       20

                                   PROPOSAL 3

               RATIFICATION OF SELECTION OF INDEPENDENT AUDITORS

    Subject to ratification by the stockholders, the Board of Directors has
selected the firm of Deloitte & Touche LLP as the Company's independent auditors
for the current year. Deloitte & Touche LLP has served as the Company's
independent auditors since its organization.

    Representatives of Deloitte & Touche LLP are expected to be present at the
Annual Meeting. They will have the opportunity to make a statement if they
desire to do so and will also be available to respond to appropriate questions
from stockholders.

    If the stockholders do not ratify the selection of Deloitte & Touche LLP as
the Company's independent auditors, the selection of such auditors will be
reconsidered by the Board of Directors.

    THE BOARD OF DIRECTORS RECOMMENDS THAT THE STOCKHOLDERS VOTE FOR THE
RATIFICATION OF THE SELECTION OF DELOITTE & TOUCHE LLP TO SERVE AS THE COMPANY'S
INDEPENDENT AUDITORS FOR THE CURRENT FISCAL YEAR.

                                       21

                             ADDITIONAL INFORMATION

OTHER MATTERS

    The Board of Directors does not know of any other matters that may come
before the Annual Meeting. However, if any other matters are properly presented
at the meeting, it is the intention of the persons named in the accompanying
proxy or their substitutes acting hereunder, to vote, or otherwise act, in
accordance with their best judgment on such matters.

SECTION 16(a) BENEFICIAL OWNERSHIP REPORTING COMPLIANCE

    Section 16(a) of the Exchange Act requires the Company's directors,
executive officers and persons who own more than ten percent of a registered
class of the Company's equity securities to file reports of ownership on Form 3
and changes in ownership on Form 4 or 5 with the SEC. Such officers, directors
and ten-percent stockholders are also required by SEC rules to furnish the
Company with copies of all Section 16(a) reports they file. Based solely on its
review of the copies of such forms received by it, or written representation
from certain reporting persons that they were not required to file a Form 5, the
Company believes that, during the fiscal year ended December 31, 2000, its
officers, directors and ten-percent stockholders complied with all
Section 16(a) filing requirements applicable to such individuals.

    The following executive officers and current and former directors each
omitted due to an administrative error to report on a Form 5 for fiscal year
1998 the grant on December 1, 1998 of stock options in the following amounts,
each at an exercise price of $23.75: Justin D. Benincasa (40,000), Alan L. Box
(25,000), Steven B. Dodge (300,000), James S. Eisenstein (100,000), J. Michael
Gearon, Jr. (100,000), Fred R. Lummis (25,000), Randall T. Mays (25,000), Thomas
H. Stoner (25,000), Douglas C. Weist (125,000), Maggie Wilderotter (25,000) and
Joseph L. Winn (125,000). Upon discovery of the error, these option grants were
reported on a Form 5 for each of the above persons filed in April 2001. Also,
Mr. Gearon inadvertently omitted to report on a Form 5 for fiscal year 1999 two
gifts totalling 2,890 shares. Mr. Gearon filed an amended Form 5 in March and
May 2000 to report the gifts and to correct his end of period holdings.

PROPOSALS OF STOCKHOLDERS

    Proposals of stockholders intended to be presented at the 2002 Annual
Meeting pursuant to Rule 14a-8 promulgated under the Securities Exchange Act of
1934 must be received by the Company no later than December 1, 2001 in order to
be included in the proxy statement and form of proxy relating to the meeting. In
addition, such proposals must comply with the other requirements of Rule 14a-8.

    If a stockholder of the Company wishes to present a proposal before the 2002
Annual Meeting, but does not wish to have the proposal considered for inclusion
in the Company's proxy statement and proxy card, such stockholder must also give
written notice to American Tower Corporation, 116 Huntington Avenue, Boston,
Massachusetts 02116, Attention: Secretary of the Company. If a stockholder fails
to deliver such notice so that it is received by the Secretary no later than
February 12, 2002, then proxies designated by the Board of Directors of the
Company will have discretionary authority to vote on any such proposal.

                                       22

ANNUAL REPORT ON FORM 10-K

    A COPY OF THE COMPANY'S ANNUAL REPORT ON FORM 10-K FOR THE FISCAL YEAR ENDED
DECEMBER 31, 2000 AS FILED WITH THE SEC, EXCEPT FOR EXHIBITS, WILL BE FURNISHED
WITHOUT CHARGE TO ANY STOCKHOLDER UPON WRITTEN REQUEST TO THE DIRECTOR OF
INVESTOR RELATIONS, AMERICAN TOWER CORPORATION, 116 HUNTINGTON AVENUE, BOSTON,
MASSACHUSETTS 02116.


                                            
                                               By Order of the Board of Directors,

                                               /s/ Steven B. Dodge
                                               Chairman of the Board, President and
                                               Chief Executive Officer


Boston, Massachusetts
March 30, 2001

                                       23

                                                                      APPENDIX I

                           AMERICAN TOWER CORPORATION

                   AUDIT COMMITTEE OF THE BOARD OF DIRECTORS
                                    CHARTER

ROLE AND INDEPENDENCE:

    The Audit Committee (the "Committee") of the Board of Directors of American
Tower Corporation (the "Corporation") assists the Board in fulfilling its
responsibility for oversight of the quality and integrity of the accounting,
auditing and reporting practices of the Corporation and such other duties as
directed by the Board. The independent auditor is ultimately accountable to the
Board and the Committee, as representatives of the stockholders. The Committee
(subject to any action that may be taken by the Board) shall have the ultimate
authority and responsibility to select (or nominate for stockholder approval),
evaluate and, where appropriate, replace the independent auditor. The Committee
shall be responsible for overseeing the independence of the independent auditor.

    The Committee is expected to maintain free and open communication (including
private executive sessions at least annually) with the independent auditor, the
internal auditors and management of the Corporation. In discharging this
oversight role, the Committee is empowered to investigate any matter brought to
its attention, with full access to all books, records, facilities and personnel
of the Corporation and the power to retain outside counsel, accountants or other
experts for this purpose.

    This charter shall be reviewed, updated and approved annually by the
Committee and filed with the Corporation's Proxy Statement at least once every
three years starting in 2001.

MEMBERSHIP:

    The Committee shall be comprised of not less than three members of the
Board, selected annually by the Board. The Committee's composition will meet the
independence and experience requirements of the Audit Committee Policy of the
NYSE. Accordingly, all of the members will be directors:

    1.  Who have no relationship to the Corporation that may interfere with the
       exercise of their independence from management and the Corporation; and

    2.  Who are financially literate within a reasonable period of time after
       appointment to the Committee.

    In addition, at least one member of the Committee will have accounting or
related financial management expertise.

RESPONSIBILITIES:

The Committee's primary responsibilities include:

    - Primary input into the recommendation to the Board for the selection and
      retention of the independent auditor that audits the financial statements
      of the Corporation. In so doing, the Committee will discuss and consider
      the auditor's written affirmation that the auditor is in fact independent,
      will discuss the nature and rigor of the audit process, receive and review
      all reports and will provide to the independent auditor full access to the
      Committee (and the Board) to report on any and all appropriate matters.

    - Provision of guidance and oversight to the internal audit function of the
      Corporation including, review of the organization, plans and results of
      such activity.

    - Review of financial statements (including quarterly reports) with
      management and the independent auditor including the communications
      required by Statement of Auditing Standards

                                      I-1

RESPONSIBILITIES (CONTINUED):
     No. 61, as amended, "Communications with Audit Committees". Annually, after
      satisfactory review by the Committee, the Corporation's audited financial
      statements included in the annual report on Form 10-K will be approved by
      the Board of Directors for filing with the Securities and Exchange
      Commission.

    - Discussion with management and the independent auditors of the quality and
      adequacy of the Corporation's internal controls.

    - Discussion with management of the status of pending litigation, taxation
      matters and other areas of oversight to the legal and compliance area as
      may be appropriate.

    - Request from the independent auditors annually a formal written statement
      delineating all relationships between the auditor and the Corporation
      consistent with Independent Standards Board No. 1, discuss with the
      independent auditors any such disclosed relationships and their impact on
      the auditors' independence, and take or recommend that the Board take
      appropriate action in response to the independent auditors' report to
      satisfy itself of the auditors' independence.

    - The Committee shall prepare for inclusion where necessary in a proxy or
      information statement of the Corporation relating to an annual meeting of
      security holders at which directors are to be elected (or special meeting
      or written consents in lieu of such meeting), the report described in
      Item 306 of Regulation S-K.

    - The Committee shall direct management to advise the Committee in the event
      that the Corporation proposes to disclose or file interim financial
      information prior to completion of review of the outside auditor.

While the Committee has the responsibilities and powers set forth in this
Charter, it is not the duty of the Committee to prepare the Corporation's
financial statements, to plan or conduct audits of those financial statements,
or to determine that those financial statements are complete and accurate and in
accordance with generally accepted accounting principles. This is the
responsibility of the Corporation's management and the independent auditors. Nor
is the duty of the Committee to conduct investigations, to resolve
disagreements, if any, between management and the independent auditor or to
assure compliance with applicable laws and regulations.

                                      I-2

                                                                     APPENDIX II

                              EVERGREEN AMENDMENT

    The following is the text of Section 3 of the Stock Option Plan as proposed
to be amended (amendments appear in boldface italic type):

    "3. OPTION SHARES

        The stock subject to Options under the Plan shall be shares of Class A
    and Class B Common Stock, par value $.01 per share (the "Stock"), provided,
    however, that after the consummation of the ATC Merger as defined in the
    Agreement and Plan of Merger by and between the Company and American Tower
    Corporation, dated December 12, 1997, as may be amended, any Options granted
    shall be for shares of Class A. The total amount of the Stock with respect
    to which Options may be granted (the "Option Pool"), shall not exceed in the
    aggregate 24,000,000 shares; PROVIDED, HOWEVER, AND SUBJECT TO THE
    LIMITATION BELOW REGARDING SHARES AVAILABLE FOR GRANTS OF ISOS, THE NUMBER
    OF SHARES AUTHORIZED FOR ISSUANCE UNDER THE PLAN SHALL INCREASE EACH
    SEPTEMBER 30, COMMENCING SEPTEMBER 30, 2001, BY AN AMOUNT EQUAL TO THE
    LESSER OF:

    (I) THE NUMBER OF SHARES OF CLASS A COMMON STOCK NECESSARY SO THAT THE
    NUMBER OF SHARES AUTHORIZED FOR ISSUANCE UNDER THE PLAN EQUALS 12% OF THE
    NUMBER OF MODIFIED FULLY-DILUTED SHARES ("FDS") OF COMMON STOCK ON SUCH
    SEPTEMBER 30, DETERMINED BY THE FOLLOWING FORMULA:


                                                  
         ANNUAL INCREASE = (12% - X%) X FDS,



                                
        WHERE X% =      OPTION POOL   X 100
                        ----------
                            FDS



                                  
        WHERE THE OPTION POOL =      FOR SEPTEMBER 30, 2001, 24,000,000 SHARES
                                     AND FOR EACH ANNIVERSARY THEREAFTER
                                     24,000,000 SHARES, PLUS ANY ANNUAL
                                     INCREASES OCCURRING PRIOR TO SUCH
                                     ANNIVERSARY.


           FDS EQUALS ON EACH SEPTEMBER 30 THE FOLLOWING:

               - THE TOTAL NUMBER OF SHARES OF ALL CLASSES OF COMMON STOCK
                 OUTSTANDING; PLUS

               - THE TOTAL NUMBER OF SHARES OF ALL CLASSES OF COMMON STOCK
                 RESERVED FOR ISSUANCE IN RESPECT OF OUTSTANDING:

                   - CONVERTIBLE SECURITIES (OTHER THAN CLASS B AND CLASS C
                     COMMON STOCK);

                   - OPTIONS ASSUMED OR ISSUED BY THE COMPANY IN CONNECTION WITH
                     MERGERS AND ACQUISITIONS; AND

                   - WARRANTS; MINUS

               - THE TOTAL NUMBER OF SHARES OF ALL CLASSES OF COMMON STOCK
                 OUTSTANDING AS A RESULT OF EXERCISES OF OPTIONS GRANTED UNDER
                 THE PLAN OR ANY OTHER EMPLOYEE, DIRECTOR OR CONSULTANT OPTIONS
                 THAT THE COMPANY MAY APPROVE, OTHER THAN OPTIONS GRANTED UNDER
                 ANY EMPLOYEE STOCK PURCHASE PLAN AND OPTIONS ASSUMED OR ISSUED
                 BY THE COMPANY IN CONNECTION WITH MERGERS AND ACQUISITIONS; OR

    (II) A LESSER NUMBER THAN THE NUMBER CALCULATED PURSUANT TO CLAUSE (I), AS
    MAY BE DETERMINED BY THE BOARD.

                                      II-1

    IF THE ANNUAL INCREASE AS CALCULATED IN CLAUSE (I) ON ANY SUCH SEPTEMBER 30
    IS A NEGATIVE NUMBER, THEN NO ANNUAL INCREASE SHALL OCCUR FOR THAT
    SEPTEMBER 30.

        In the event that any outstanding Option shall expire for any reason or
    shall terminate by reason of the death or severance of employment of the
    Optionee, the surrender of any such Option, or any other cause, the shares
    of Stock allocable to the unexercised portion of such Option may again be
    subject to an option under the Plan, SUBJECT, HOWEVER, IN THE CASE OF ISOS
    TO ANY LIMITATIONS UNDER THE CODE. The maximum number of shares of Stock
    subject to Options that may be granted to any Optionee in the aggregate in
    any calendar year shall not exceed 5,000,000 shares. THE MAXIMUM CUMULATIVE
    NUMBER OF SHARES OF STOCK AVAILABLE FOR GRANTS OF ISOS UNDER THE PLAN IS
    50,000,000 SHARES. ALL SHARES REFERENCES IN THIS SECTION 3 SHALL BE SUBJECT
    TO ADJUSTMENT IN ACCORDANCE WITH THE PROVISIONS OF SECTION 17."

                                      II-2



                                                                  APPENDIX III










                             1997 STOCK OPTION PLAN
                       AMERICAN TOWER SYSTEMS CORPORATION

                             1997 Stock Option Plan
                    As Amended and Restated on March 15, 2001



                            ------------------------

                               As approved by the
                      Board of Directors on March 15, 2001,
                         subject to stockholder approval
                            ------------------------


                               As approved by the
                             Stockholders on _______

                            ------------------------








                       AMERICAN TOWER SYSTEMS CORPORATION
                             1997 STOCK OPTION PLAN

                                TABLE OF CONTENTS



                                                                            PAGE
                                                                         
1.       PURPOSE........................................................      1

2.       ADMINISTRATION OF THE PLAN.....................................      1

3.       OPTION SHARES..................................................      2

4.       AUTHORITY TO GRANT OPTIONS.....................................      3

5.       WRITTEN AGREEMENT..............................................      3

6.       ELIGIBILITY....................................................      3

7.       OPTION PRICE...................................................      4

8.       DURATION OF OPTIONS............................................      4

9.       VESTING PROVISIONS.............................................      5

10.      EXERCISE OF OPTIONS............................................      5

11.      TRANSFERABILITY OF OPTIONS.....................................      6

12.      TERMINATION OF EMPLOYMENT OR INVOLVEMENT
         OF OPTIONEE WITH THE COMPANY...................................      6

13.      REQUIREMENTS OF LAW............................................      7

14.      NO RIGHTS AS STOCKHOLDER.......................................      8

15.      EMPLOYMENT OBLIGATION..........................................      8

16.      FORFEITURE AS A RESULT OF TERMINATION FOR CAUSE................      8

17.      CHANGES IN THE COMPANY'S CAPITAL STRUCTURE.....................      9

18.      AMENDMENT OR TERMINATION OF PLAN...............................     10

19.      EFFECTIVE DATE AND DURATION OF THE PLAN........................     11



                                       i





                       AMERICAN TOWER SYSTEMS CORPORATION

                             1997 STOCK OPTION PLAN

1. PURPOSE

     The purpose of this 1997 Stock Option Plan (the "Plan") is to encourage
directors, consultants and employees of American Tower Systems Corporation (the
"Company") and its Subsidiaries (as hereinafter defined) to continue their
association with the Company and its Subsidiaries, by providing opportunities
for such persons to participate in the ownership of the Company and in its
future growth through the granting of stock options (the "Options") which may be
options designed to qualify as incentive stock options (within the meaning of
Section 422 of the Internal Revenue Code of 1986, as amended (the "Code") (an
"ISO"), or options not intended to qualify for any special tax treatment under
the Code (a "NQO"). The term "Subsidiary" as used in the Plan means a
corporation or other business organization of which the Company owns, directly
or indirectly through an unbroken chain of ownership, fifty percent (50%) or
more of the total combined voting power of all classes of stock.

2. ADMINISTRATION OF THE PLAN

     The Plan shall be administered by a committee (the "Committee") consisting
of two or more members of the Company's Board of Directors (the "Board"). The
Committee shall from time to time determine to whom options or other rights
shall be granted under the Plan, whether options granted shall be incentive
stock options ("ISOs") or nonqualified stock options ("NSOs"), the terms of the
options or other rights, and the number of shares that may be granted under
options. The Committee shall report to the Board the names of individuals to
whom stock or options or other rights are to be granted, the number of shares
covered, and the terms and conditions of each grant. The determinations
described in this Section 2 may be made by the Committee or by the Board, as the
Board shall direct in its discretion, and references in the Plan to the
Committee shall be understood to refer to the Board in any such case.

     The Committee shall select one of its members as Chairman and shall hold
meetings at such times and places as it may determine. A majority of the
Committee shall constitute a quorum, and acts of the Committee at which a quorum
is present, or acts reduced to or approved in writing by all the members of the
Committee, shall be the valid acts of the Committee. The Committee shall have
the authority to adopt, amend, and rescind such rules and regulations as, in its
opinion, may be advisable in the administration of the Plan. All questions of
interpretation and application of such rules and regulations, of the Plan and of
options granted thereunder (the "Options"), shall be subject to the
determination of the Committee, which shall be final and binding. The Plan shall
be administered in such a manner as to permit those Options granted hereunder
and specially designated under Section 5 hereof as an ISO to qualify as
incentive stock options as described in Section 422 of the Internal Revenue Code
of 1986, as amended (the "Code").

     For so long as Section 16 of the Securities Exchange Act of 1934, as
amended from time to time (the "Exchange Act"), is applicable to the Company,
each member of the Committee shall be a "non-employee director" or the
equivalent within the meaning of


                                       1



Rule 16b-3 under the Exchange Act, and, for so long as Section 162(m) of the
Code is applicable to the Company, an "outside director" within the meaning of
Section 162 of the Code and the regulations thereunder.

     With respect to persons subject to Section 16 of the Exchange Act
("Insiders"), transactions under the Plan are intended to comply with all
applicable conditions of Rule 16b-3 or its successor under the Exchange Act. To
the extent any provision of the Plan or action by the Committee fails to so
comply, it shall be deemed to be modified so as to be in compliance with such
Rule, or, if such modification is not possible, it shall be deemed to be null
and void, to the extent permitted by law and deemed advisable by the Committee.

3. OPTION SHARES

     The stock subject to Options under the Plan shall be shares of Class A and
Class B Common Stock, par value $.01 per share (the "Stock"), provided, however,
that after the consummation of the ATC Merger as defined in the Agreement and
Plan of Merger by and between the Company and American Tower Corporation, dated
December 12, 1997, as may be amended, any Options granted shall be for shares of
Class A. The total amount of the Stock with respect to which Options may be
granted (the "Option Pool"), shall not exceed in the aggregate 24,000,000
shares; provided, however, and subject to the limitation below regarding shares
available for grants of ISOs, the number of shares authorized for issuance under
the Plan shall increase each September 30, commencing September 30, 2001, by an
amount equal to the lesser of:

     (i)  the number of shares of Class A Common Stock necessary so that the
          number of shares authorized for issuance under the Plan equals 12% of
          the number of modified fully-diluted shares ("FDS") of Common Stock
          on such September 30, determined by the following formula:

                       Annual Increase = (12% - X%) x FDS,

                                    Option Pool
                       where X% =   -----------    x 100
                                       FDS

                       where  the Option Pool = For September 30, 2001,
                                                24,000,000 shares and for each
                                                anniversary thereafter
                                                24,000,000 shares, plus any
                                                Annual Increases occurring
                                                prior to such anniversary.

      FDS equals on each September 30 the following:

      o the total number of shares of all classes of Common Stock outstanding;
        PLUS

      o the total number of shares of all classes Common Stock reserved for
        issuance in respect of outstanding:

          - convertible securities (other than Class B and Class C Common
            Stock);

          - options assumed or issued by the Company in connection with mergers
            and acquisitions; and

          - warrants; MINUS

      o the total number of shares of all classes of Common Stock outstanding
        as a result of exercise of options granted under the Plan or any other
        employee, director or consultant options that the Company may approve,
        other than options granted under any employee stock purchase plan and
        options assumed or issued by the Company in connection with mergers
        and acquisitions; or


                                      2



     (ii) a lesser number than the number calculated pursuant to clause (i)
          as may be determined by the Board.

If the Annual Increase as calculated in clause (i) on any such September 30
is a negative number, then no Annual Increase shall occur for that September
30.

     In the event that any outstanding Option shall expire for any reason or
shall terminate by reason of the death or severance of employment of the
Optionee, the surrender of any such Option, or any other cause, the shares of
Stock allocable to the unexercised portion of such Option may again be
subject to an option under the Plan subject, however, in the case of ISOs to
any limitations under the Code. The maximum number of shares of Stock subject
to Options that may be granted to any Optionee in the aggregate in any
calendar year shall not exceed 5,000,000 shares. The maximum cumulative
number of shares available for grants of ISOs under the Plan is 50,000,000
shares. All shares references in this Section 3 shall be subject to
adjustment in accordance with the provisions of Section 17.

4. AUTHORITY TO GRANT OPTIONS

     The Committee may determine, from time to time, which employees of the
Company or any Subsidiary or other persons shall be granted Options under the
Plan, the terms of the Options (including without limitation whether an Option
shall be an ISO or a NQO) and the number of shares which may be purchased under
the Option or Options. Without limiting the generality of the foregoing, the
Committee may from time to time grant: (a) to such employees (other than
employees of a Subsidiary which is not a corporation) as it shall determine an
Option or Options to buy a stated number of shares of Stock under the terms and
conditions of the Plan which Option or Options will to the extent so designated
at the time of grant constitute an ISO; and (b) to such eligible directors,
employees or other persons as it shall determine an Option or Options to buy a
stated number of shares of Stock under the terms and conditions of the Plan
which Option or Options shall constitute a NQO. Subject only to any applicable
limitations set forth elsewhere in the Plan, the number of shares of Stock to be
covered by any Option shall be as determined by the Committee.

5. WRITTEN AGREEMENT

     Each Option granted hereunder shall be embodied in an option agreement (the
"Option Agreement") substantially in the form of Exhibit 1, which shall be
signed by the Optionee and by the Chief Executive Officer, Chief Financial
Officer or the Corporate Controller of the Company for and in the name and on
behalf of the Company. An Option Agreement may contain such restrictions on
exercisability and such other provisions not inconsistent with the Plan as the
Committee in its sole and absolute discretion shall approve.

6. ELIGIBILITY

     The individuals who shall be eligible for grant of Options under the Plan
shall be employees (including officers who may be members of the Board),
directors who are not employees and other individuals, whether or not employees,
who render services of special importance to the management, operation, or
development of the Company or a Subsidiary,


                                       3



and who have contributed or may be expected to contribute materially to the
success of the Company or a Subsidiary. An employee, director or other person to
whom an Option has been granted pursuant to an Option Agreement is hereinafter
referred to as an "Optionee."

7. OPTION PRICE

     The price at which shares of Stock may be purchased pursuant to an Option
shall be specified by the Committee at the time the Option is granted, but shall
in no event be less than the par value of such shares and, in the case of an
ISO, except as set forth in the following sentence, one hundred percent (100%)
of the fair market value of the Stock on the date the ISO is granted. In the
case of an employee who owns (or is considered under Section 424(d) of the Code
as owning) stock possessing more than ten percent (10%) of the total combined
voting power of all classes of stock of the Company or any Subsidiary, the price
which shares of Stock may be so purchased pursuant to an ISO shall be not less
than one hundred and ten percent (110%) of the fair value of the Stock on the
date the ISO is granted.

     For purposes of the Plan, the "fair market value" of a share of Stock on
any date specified herein, shall mean (a) the last reported sales price, regular
way, or, in the event that no sale takes place on such day, the average of the
reported closing bid and asked prices, regular way, in either case (i) as
reported on the New York Stock Exchange Composite Tape, or (ii) if the Stock is
not listed or admitted to trading on the New York Stock Exchange, on the
principal national securities exchange on which such security is listed or
admitted to trading, or (iii) if not then listed or admitted to trading on any
national securities exchange, on the NASDAQ National Market System; or (b) if
the Stock is not quoted on such National Market System, (i) the average of the
closing bid and asked prices on each such day in the over-the-counter market as
reported by NASDAQ, or (ii) if bid and asked prices for such security on each
such day shall not have been reported through NASDAQ, the average of the bid and
asked prices for such day as furnished by any New York Stock Exchange member
firm regularly making a market in such security selected for such purpose by the
Committee; or (c) if the Stock is not then listed or admitted to trading on any
national exchange or quoted in the over-the-counter market, the fair value
thereof determined in good faith by the Committee as of a date which is within
thirty (30) days of the date with respect to which the determination is to be
made; provided, however, that any method of determining fair market value
employed by the Committee with respect to an ISO shall be consistent with any
applicable laws or regulations pertaining to "incentive stock options."

8. DURATION OF OPTIONS

     The duration of any Option shall be specified by the Committee in the
Option Agreement, but no ISO shall be exercisable after the expiration of ten
(10) years, and no NQO shall be exercisable after the expiration of ten (10)
years and one (1) day, from the date such Option is granted. In the case of any
employee who owns (or is considered under Section 424(d) of the Code as owning)
stock possessing more than ten percent (10%) of the total combined voting power
of all classes of stock of the Company or any Subsidiary, no ISO shall be
exercisable after the expiration of five (5) years from the date such Option is
granted. The Committee, in its sole and absolute discretion, may extend any
Option theretofore granted subject to the aforesaid limits and may provide that
an Option shall be exercisable during its entire duration or during any lesser
period of time.


                                       4



9. VESTING PROVISIONS

     Each Option may be exercised so long as it is valid and outstanding from
time to time, in part or as a whole, in such manner and subject to such
conditions as the Committee, in its sole and absolute discretion, may provide in
the Option Agreement.

10. EXERCISE OF OPTIONS

     Options shall be exercised by the delivery of written notice to the Company
setting forth the number of shares of Stock with respect to which the Option is
to be exercised, accompanied by payment of the option price of such shares,
which payment shall be made, subject to the alternative provisions of this
Section, in cash or by such cash equivalents, payable to the order of the
Company in an amount in United States dollars equal to the option price of such
shares, as the Committee in its sole and absolute discretion shall consider
acceptable. Such notice shall be delivered in person to the Secretary of the
Company or shall be sent by registered mail, return receipt requested, to the
Secretary of the Company, in which case delivery shall be deemed made on the
date such notice is deposited in the mail.

     Alternatively, if the Option Agreement so specifies, and subject to such
rules as may be established by the Committee, payment of the option price may be
made through a so-called "cashless exercise" procedure, under which the Optionee
shall deliver irrevocable instructions to a broker to sell shares of Stock
acquired upon exercise of the Option and to remit promptly to the Company a
sufficient portion of the sale proceeds to pay the option price and any tax
withholding resulting from such exercise.

     Alternatively, payment of the option price may be made, in whole or in
part, in shares of Stock owned by the Optionee; provided, however, that the
Optionee may not make payment in shares of Stock that he acquired upon the
earlier exercise of any ISO (or other "incentive stock option"), unless and
until he has held the shares until at least two (2) years after the date the ISO
(or such other incentive stock option) was granted and at least one (1) year
after the date the ISO (or such other option) was exercised. If payment is made
in whole or in part in shares of Stock, then the Optionee shall deliver to the
Company in payment of the option price of the shares with respect of which such
Option is exercised (a) certificates registered in the name of such Optionee
representing a number of shares of Stock legally and beneficially owned by such
Optionee, free of all liens, claims and encumbrances of every kind, and having a
fair market value on the date of delivery of such notice equal to the option
price of the shares of Stock with respect to which such Option is to be
exercised, such certificates to be accompanied by stock powers duly endorsed in
blank by the record holder of the shares of Stock represented by such
certificates; and (b) if the option price of the shares with respect to which
such Option is to be exercised exceeds such fair market value, cash or such cash
equivalents payable to the order to the Company, in an amount in United States
dollars equal to the amount of such excess, as the Committee in its sole and
absolute discretion shall consider acceptable. Notwithstanding the foregoing
provisions of this Section, the Committee, in its sole and absolute discretion
(i) may refuse to accept shares of Stock in payment of the option price of the
shares of Stock with respect to which such Option is to be exercised and, in
that event, any certificates representing shares of Stock which were delivered
to the Company with such written notice shall be returned to such Optionee
together with notice by the Company to such Optionee of the refusal of the
Committee to


                                       5



accept such shares of Stock and (ii) may accept, in lieu of actual delivery of
stock certificates, an attestation by the Optionee substantially in the form
attached herewith as Exhibit C or such other form as may be deemed acceptable by
the Committee that he or she owns of record the shares to be tendered free and
clear of all liens, claims and encumbrances of every kind.

     Alternatively, if the Option Agreement so specifies, payment of the option
price may be made in part by a promissory note executed by the Optionee and
containing the following terms and conditions (and such others as the Committee
shall, in its sole and absolute discretion determine from time to time): (a) it
shall be collaterally secured by the shares of Stock obtained upon exercise of
the Option; (b) repayment shall be made on demand by the Company and, in any
event, no later than three (3) years from the date of exercise; and (c) the note
shall bear interest at a rate as determined by the Committee, payable monthly
out of a payroll deduction provision; provided, however, that notwithstanding
the foregoing (i) an amount not less than the par value of the shares of Stock
with respect to which the Option is being exercised must be paid in cash, cash
equivalents, or shares of Stock in accordance with this Section, and (ii) the
payment of such exercise price by promissory note does not violate any
applicable laws or regulations, including, without limitation, Delaware
corporate law or applicable margin lending rules. The decision as to whether to
permit partial payment by a promissory note for shares of Stock to be issued
upon exercise of any Option granted shall rest entirely in the sole and absolute
discretion of the Committee.

     As promptly as practicable after the receipt by the Company of (a) written
notice from the Optionee setting forth the number of shares of Stock with
respect to which such Option is to be exercised and (b) payment of the option
price of such shares in the form required by the foregoing provisions of this
Section, the Company shall cause to be delivered to such Optionee certificates
representing the number of shares with respect to which such Option has been so
exercised (less a number of shares equal to the number of shares as to which
ownership was attested under the procedure described in clause (ii) of the next
preceding paragraph).

11. TRANSFERABILITY OF OPTIONS

     Options shall not be transferable by the Optionee otherwise than by will or
under the laws of descent and distribution, and shall be exercisable during his
or her lifetime only by the Optionee, except that the Committee may specify in
an Option Agreement that pertains to an NQO that the Optionee may transfer such
NQO to a member of the Immediate Family of the Optionee, to a trust solely for
the benefit of the Optionee and the Optionee's Immediate Family, or to a
partnership or limited liability company whose only partners or members are the
Optionee and members of the Optionee's Immediate Family. "Immediate Family"
shall mean, with respect to any Optionee, such Optionee's child, stepchild,
grandchild, parent, stepparent, grandparent, spouse, sibling, mother-in-law,
father-in-law, son-in-law, daughter-in-law, brother-in-law, or sister-in-law,
and shall include adoptive relationships.

12. TERMINATION OF EMPLOYMENT OR INVOLVEMENT OF OPTIONEE WITH THE COMPANY

     For purposes of this Section, employment by or involvement with (in the
case of an Optionee who is not an employee) a Subsidiary shall be considered
employment by or


                                       6


involvement with the Company. Except as otherwise set forth in the Option
Agreement, after the Optionee's termination of employment with the Company other
than by reason of death or disability, including his retirement in good standing
from the employ of the Company for reasons of age under the then established
rules of the Company, the Option shall terminate on the earlier of the date of
its expiration or three (3) months after the date of such termination or
retirement. After the death of the Optionee, his or her executors,
administrators or any persons to whom his or her Option may be transferred by
will or by the laws of descent and distribution shall have the right to exercise
the Option to the extent to which the Optionee was entitled to exercise the
Option. In the event that such termination is a result of disability, the
Optionee shall have the right to exercise the Option pursuant to its terms as if
such Optionee continued as an employee.

     Authorized leave of absence or absence on military or government service
shall not constitute severance of the employment relationship between the
Company and the Optionee for purposes of the Plan, provided that either (a) such
absence is for a period of no more than ninety (90) days or (b) the Employee's
right to re-employment after such absence is guaranteed either by statute or by
contract.

     For Optionees who are not employees of the Company, options shall be
exercisable for such periods following the termination of the Optionee's
involvement with the Company as may be set forth in the Option Agreement.

13. REQUIREMENTS OF LAW

     The Company shall not be required to sell or issue any shares of Stock upon
the exercise of any Option if the issuance of such shares shall constitute or
result in a violation by the Optionee or the Company of any provisions of any
law, statute or regulation of any governmental authority. Specifically, in
connection with the Securities Act of 1933, as amended (the "Securities Act"),
and any applicable state securities or "blue sky" law (a "Blue Sky Law"), upon
exercise of any Option the Company shall not be required to issue such shares
unless the Committee has received evidence satisfactory to it to the effect that
the holder of such Option will not transfer such shares except pursuant to a
registration statement in effect under the Securities Act and Blue Sky Laws or
unless an opinion of counsel satisfactory to the Company has been received by
the Company to the effect that such registration and compliance is not required.
Any determination in this connection by the Committee shall be final, binding
and conclusive. The Company shall not be obligated to take any action in order
to cause the exercise of an Option or the issuance of shares of Stock pursuant
thereto to comply with any law or regulations of any governmental authority,
including, without limitation, the Securities Act or applicable Blue Sky Law.

     Notwithstanding any other provision of the Plan to the contrary, the
Company may refuse to permit transfer of shares of Stock if in the opinion of
its legal counsel such transfer would violate federal or state securities laws
or subject the Company to liability thereunder. Any sale, assignment, transfer,
pledge or other disposition of shares of Stock received upon exercise of any
Option (or any other shares or securities derived therefrom) which is not in
accordance with the provisions of this Section shall be void and of no effect
and shall not be recognized by the Company.



                                       7




     LEGEND ON CERTIFICATES. The Committee may cause any certificate
representing shares of Stock acquired upon exercise of an Option (and any other
shares or securities derived therefrom) to bear a legend to the effect that the
securities represented by such certificate have not been registered under the
Federal Securities Act of 1933, as amended, or any applicable state securities
laws, and may not be sold, assigned, transferred, pledged or otherwise disposed
of except in accordance with the Plan and applicable agreements binding the
holder and the Company or any of its stockholders.

14. NO RIGHTS AS STOCKHOLDER

     No Optionee shall have any rights as a stockholder with respect to shares
covered by his or her Option until the date of issuance of a stock certificate
for such shares; except as otherwise provided in Section 17, no adjustment for
dividends or otherwise shall be made if the record date therefor is prior to the
date of issuance of such certificate.

15. EMPLOYMENT OBLIGATION

     The granting of any Option shall not impose upon the Company or any
Subsidiary any obligation to employ or continue to employ any Optionee, or to
engage or retain the services of any person, and the right of the Company or any
Subsidiary to terminate the employment or services of any person shall not be
diminished or affected by reason of the fact that an Option has been granted to
him or her. The existence of any Option shall not be taken into account in
determining any damages relating to termination of employment or services for
any reason.

16. FORFEITURE AS A RESULT OF TERMINATION FOR CAUSE

     Notwithstanding any provision of the Plan to the contrary, if the Committee
determines, after full consideration of the facts presented on behalf of the
Company and an Optionee, that

     (a) the Optionee has been engaged in fraud, embezzlement, theft, commission
of a felony or dishonesty in the course of his or her employment by or
involvement with the Company or a Subsidiary, which damaged the Company or a
Subsidiary, or has made unauthorized disclosure of trade secrets or other
proprietary information of the Company or a Subsidiary or of a third party who
has entrusted such information to the Company or a Subsidiary, or

     (b) the Optionee's employment or involvement was otherwise terminated for
"cause," as defined in any employment agreement with the Optionee, if
applicable, or if there is no such agreement, as determined by the Committee,
which may determine that "cause" includes among other matters the willful
failure or refusal of the Optionee to perform and carry out his or her assigned
duties and responsibilities diligently and in a manner satisfactory to the
Committee, then the Optionee's right to exercise an Option shall terminate as of
the date of such act (in the case of (a)) or such termination (in the case of
(b)) and the Optionee shall forfeit all unexercised Options. If an Optionee
whose behavior the Company asserts falls within the provisions of (a) or (b)
above has exercised or attempts to exercise an Option prior to a decision of the
Committee, the Company shall not be required to recognize such



                                       8



exercise until the Committee has made its decision and, in the event of any
exercise shall have taken place, it shall be of no force and effect (and void AB
INITIO) if the Committee makes an adverse determination; provided, however, if
the Committee finds in favor of the Optionee then the Optionee will be deemed to
have exercised such Option retroactively as of the date he or she originally
gave written notice of his or her attempt to exercise or actual exercise, as the
case may be. The decision of the Committee as to the cause of an Optionee's
discharge and the damage done to the Company or a Subsidiary shall be final,
binding and conclusive. No decision of the Committee, however, shall affect in
any manner the finality of the discharge of such Optionee by the Company or a
Subsidiary.

17. CHANGES IN THE COMPANY'S CAPITAL STRUCTURE

     The existence of outstanding Options shall not affect in any way the right
or power of the Company or its stockholders to make or authorize any or all
adjustments, recapitalizations, reorganizations or other changes in the
Company's capital structure or its business or any merger or consolidation of
the Company or any issue of bonds, debentures, preferred or preference stock,
whether or not convertible into the Stock or other securities, ranking prior to
the Stock or affecting the rights thereof, or warrants, rights or options to
acquire the same, or the dissolution or liquidation of the Company or any sale
or transfer of all or any part of its assets or business or any other corporate
act or proceeding, whether of a similar character or otherwise.

     The number of shares of Stock in the Option Pool (less the number of shares
theretofore delivered upon exercise of Options) and the number of shares of
Stock covered by any outstanding Option and the price per share payable upon
exercise thereof (provided that in no event shall the option price be less than
the par value of such shares) shall be proportionately adjusted for any increase
or decrease in the number of issued and outstanding shares of Stock resulting
from any subdivision, split, combination or consolidation of shares of Stock or
the payment of a dividend in shares of stock or other securities of the Company
on the Stock. The decision of the Board as to the adjustment, if any, required
by the provisions of this Section shall be final, binding and conclusive.

     If the Company merges or consolidates with a wholly-owned subsidiary for
the purpose of reincorporating itself under the laws of another jurisdiction,
the Optionees will be entitled to acquire shares of Stock of the reincorporated
Company upon the same terms and conditions as were in effect immediately prior
to such reincorporation (unless such reincorporation involves a change in the
number of shares or the capitalization of the Company, in which case
proportional adjustments shall be made as provided above) and the Plan, unless
otherwise rescinded by the Board, will remain the Plan of the reincorporated
Company.

     Except as otherwise provided in the preceding paragraph, if the Company is
merged or consolidated with another corporation, whether or not the Company is
the surviving entity, or if the Company is liquidated or sells or otherwise
disposes of all or substantially all of its assets to another entity while
unexercised Options remain outstanding under the Plan, or if other circumstances
occur in which the Board in its sole and absolute discretion deems it
appropriate for the provisions of this paragraph to apply (in each case, an
"Applicable Event"), then (a) each holder of an outstanding Option shall be
entitled, upon exercise of such



                                       9




Option, to receive in lieu of shares of Stock, such stock or other securities or
property as he or she would have received had he exercised such option
immediately prior to the Applicable Event; or (b) the Board may, in its sole and
absolute discretion, waive, generally or in one or more specific cases, any
limitations imposed pursuant to Section 9 so that some or all Options from and
after a date prior to the effective date of such Applicable Event, specified by
the Board, in its sole and absolute discretion, shall be exercisable in full; or
(c) the Board may, in its sole and absolute discretion, cancel all outstanding
and unexercised Options as of the effective date of any such Applicable Event;
or (d) the Board may, in its sole discretion, convert some or all Options into
options to purchase the stock or other securities of the surviving corporation
pursuant to an Applicable Event; or (e) the Board may, in its sole and absolute
discretion, assume the outstanding and unexercised options to purchase stock or
other securities of any corporation and convert such options into Options to
purchase Stock, whether pursuant to this Plan or not, pursuant to an Applicable
Event; provided, however, notice of any such cancellation pursuant to clause (c)
shall be given to each holder of an Option not less than thirty (30) days
preceding the effective date of such Applicable Event, and provided further,
however, that the Board may, in its sole and absolute discretion, waive,
generally or in one or more specific instances, any limitations imposed pursuant
to Section 9 with respect to any Option so that such Option shall be exercisable
in full or in part, as the Board may, in its sole and absolute discretion,
determine, during such thirty (30) day period.

     Except as expressly provided herein, the issue by the Company of shares of
Stock or other securities of any class or series or securities convertible into
or exchangeable or exercisable for shares of Stock or other securities of any
class or series for cash or property or for labor or services either upon direct
sale or upon the exercise of rights or warrants to subscribe therefor, or upon
conversion of shares or obligations of the Company convertible into such shares
or other securities, shall not affect, and no adjustment by reason thereof shall
be made with respect to, the number, class or price of shares of Stock then
subject to outstanding Options.

18. AMENDMENT OR TERMINATION OF PLAN

     The Board may, in its sole and absolute discretion, modify, revise or
terminate the Plan at any time and from time to time; provided, however, that
without the further approval of the holders of at least a majority of the
outstanding shares of Stock, the Board may not (a) materially increase the
benefits accruing to Optionees under the Plan or make any "modifications" as
that term is defined under Section 424(h)(3) (or its successor) of the Code if
such increase in benefits or modifications would adversely affect (i) the
availability to the Plan of the protections of Section 16(b) of the Exchange
Act, if applicable to the Company, or (ii) the qualification of the Plan or any
Options for "incentive stock option" treatment under Section 422 of the Code;
(b) change the aggregate number of shares of Stock which may be issued under
Options pursuant to the provisions if the Plan either to any one employee or in
the aggregate; or (c) change the class of persons eligible to receive ISOs.
Notwithstanding the preceding sentence, the Board shall in all events have the
power and authority to make such changes in the Plan and in the regulations and
administrative provisions hereunder or in any outstanding Option as, in the
opinion of counsel for the Company, may be necessary or appropriate from time to
time to enable any Option granted pursuant to the Plan to qualify as an
incentive stock option or such other stock option as may be defined under the
Code, as amended from time to time, so as to receive preferential federal income
tax treatment.


                                       10



19. EFFECTIVE DATE AND DURATION OF THE PLAN

     The Plan shall become effective and shall be deemed to have been adopted on
November 5, 1997, unless the Plan shall have terminated earlier, the Plan shall
terminate on the tenth (10th) anniversary of its effective date, and no Option
shall be granted pursuant to the Plan after the day preceding the tenth (10th)
anniversary of its effective date.



                                        11



                       AMERICAN TOWER SYSTEMS CORPORATION

                             Stock Option Agreement

                            ------------------------

                             Option Certificate: No.

                          Specific Terms of the Option
                            ------------------------

     Subject to the terms and conditions hereinafter set forth and the terms and
conditions of the American Tower Systems Corporation 1997 Stock Option Plan (the
"Plan"), American Tower Systems Corporation, a Delaware corporation (the
"Company" which term shall include, unless the context otherwise clearly
requires, all Subsidiaries [as defined in the Plan] of the Company) hereby
grants the following option to purchase shares of Common Stock, par value $.01
per share (the "Stock") of the Company:

     1. Name of Person to Whom the Option is granted (the "Optionee"):

     2. Date of Grant of Option:

     3. Number of shares of Stock:

     4. Option Exercise Price (per share): $

     5. Term: Subject to Section 10, this Option expires at 5:00 p.m. Eastern
        Time on

     6. Exercisability: Provided that on the dates set forth below the Optionee
        is still employed by the Company or, if the Optionee is not employed
        by the Company the Optionee is still actively involved in the Company
        (as determined by the Committee) the Option will become exercisable as
        follows and as provided in Section 9 below:


        DATE                 NUMBER OF SHARES                 CUMULATIVE NUMBER





          American Tower Systems Corporation



By:
   -------------------------------         ----------------------------------
   Title:                                  (Signature of Optionee)
         ---------------------------------


Date:
     ---------------------------------

Optionee's Address:





                            OTHER TERMS OF THE OPTION

                            ------------------------

     WHEREAS, the Board of Directors (the "Board") has authorized the grant of
stock options upon certain terms and conditions set forth in the Plan and
herein; and

     WHEREAS, the Compensation Committee (the "Committee") has authorized the
grant of this stock option pursuant and subject to the terms of the Plan, a copy
of which is available from the Company and is hereby incorporated herein;

     NOW, THEREFORE, in consideration of the premises and the mutual covenants
and agreements herein contained, the Company and the Optionee, intending to be
legally bound, covenant and agree as set forth on the first page hereof and as
follows:

     7. GRANT. Pursuant and subject to the Plan, the Company does hereby grant
        to the Optionee a stock option (the "Option") to purchase from the
        Company the number of shares of Stock set forth in Section 3 on the
        first page hereof upon the terms and conditions set forth in the Plan
        and upon the additional terms and conditions contained herein. This
        Option is a [INCENTIVE] [NONQUALIFIED] stock option and [IS] [IS NOT]
        intended to qualify for special federal income tax treatment as an
        "incentive stock option" pursuant to Section 422 of the Internal
        Revenue Code of 1986, as amended (the "Code").

     8. OPTION PRICE. This Option may be exercised at the option price per share
        of Stock set forth in Section 4 on the first page hereof, subject to
        adjustment as provided herein and in the Plan.

     9. TERM AND EXERCISABILITY OF OPTION. This Option shall expire on the date
        determined pursuant to Section 5 on first page hereof and shall be
        exercisable prior to that date in accordance with and subject to the
        conditions set forth in the Plan and those conditions, if any, set
        forth in Section 6 on first page hereof. If before this Option has
        been exercised in full, the Optionee ceases to be an employee of the
        Company for any reason other than a termination for a reason specified
        in Section 16 of the Plan, the Optionee may exercise this Option to
        the extent that he or she might have exercised it on the date of
        termination of his or her employment, but only during the period
        ending on the earlier of (a) the date on which the Option expires in
        accordance with Section 5 of this Agreement or (b) three (3) months
        after the date of termination of the Optionee's employment with the
        Company. However, if the Optionee dies before the date of expiration
        of this Option and while in the employ of the Company or during the
        three month period described in the preceding sentence, or in the
        event of the retirement of the Optionee for reasons of disability
        (within the meaning of Code (S) 22(e)(3)), the Option shall terminate
        only on such date of expiration. If the Optionee dies before this
        Option has been exercised in full, the personal representative of the
        Optionee may exercise this Option as set forth in the preceding
        sentence.



                                       2




     10. METHOD OF EXERCISE. To the extent that the right to purchase shares of
         Stock has accrued hereunder, this Option may be exercised from time to
         time by written notice to the Company substantially in the form
         attached hereto as Exhibit A, stating the number of shares with
         respect to which this Option is being exercised, and accompanied by
         payment in full of the option price for the number of shares to be
         delivered, by means of payment acceptable to the Company in accordance
         with Section 10 of the Plan. As soon as practicable after its receipt
         of such notice, the Company shall, without transfer or issue tax to
         the Optionee (or other person entitled to exercise this Option),
         deliver to the Optionee (or other person entitled to exercise this
         Option), at the principal executive offices of the Company or such
         other place as shall be mutually acceptable, a certificate or
         certificates for such shares out of theretofore authorized but
         unissued shares or reacquired shares of its Stock as the Company may
         elect; provided, however, that the time of such delivery may be
         postponed by the Company for such period as may be required for it
         with reasonable diligence to comply with any applicable requirements
         of law. Payment of the option price may be made in cash or cash
         equivalents or, in accordance with the terms and conditions of Section
         10 of the Plan, (a) in whole or in part in shares of Common Stock of
         the Company, whether or not through the attestation procedure in the
         Plan, or (b) in part by promissory note of the Optionee in the form
         attached hereto as Exhibit B; provided, however, that the Board
         reserves the right upon receipt of any written notice of exercise from
         the Optionee to require payment in cash with respect to the shares
         contemplated in such notice. If the Optionee (or other person entitled
         to exercise this Option) fails to pay for and accept delivery of all
         of the shares specified in such notice upon tender of delivery
         thereof, his or her right to exercise this Option with respect to such
         shares not paid for may be terminated by the Company.

     11. Nonassignability of Option Rights. This Option shall not be assignable
         or transferable by the Optionee except by will or by the laws of
         descent and distribution. During the life of the Optionee, this Option
         shall be exercisable only by him or her.*

     12. COMPLIANCE WITH SECURITIES ACT. The Company shall not be obligated to
         sell or issue any shares of Stock or other securities pursuant to the
         exercise of this Option unless the shares of Stock or other securities
         with respect to which this Option is being exercised are at that time
         effectively registered or exempt from registration under the
         Securities Act of 1933, as amended, and applicable state securities
         laws. In the event shares or other securities shall be issued which
         shall not be so registered, the Optionee hereby represents, warrants
         and agrees that he or she will receive such shares or other securities
         for investment and not with a view to their resale or distribution,
         and will execute an appropriate investment letter satisfactory to the
         Company and its counsel.

     13. LEGENDS. The Optionee hereby acknowledges that the stock certificate or
         certificates evidencing shares of Stock or other securities issued
         pursuant to any exercise of this Option will bear a legend setting
         forth the restrictions on their transferability described in Section
         13 hereof.

- --------
* Use different language for an Option transferable to family members.


                                       3



     14. RIGHTS AS STOCKHOLDER. The Optionee shall have no rights as a
         stockholder with respect to any shares of Stock or other securities
         covered by this Option until the date of issuance of a certificate to
         him or her for such shares or other securities. No adjustment shall be
         made for dividends or other rights for which the record date is prior
         to the date such stock certificate is issued.

     15. WITHHOLDING TAXES. The Optionee hereby agrees, as a condition to any
         exercise of this Option, to provide to the Company an amount
         sufficient to satisfy its obligation to withhold certain federal,
         state and local taxes arising by reason of such exercise (the
         "Withholding Amount") by (a) authorizing the Company to withhold the
         Withholding Amount from his or her cash compensation, or (b) remitting
         the Withholding Amount to the Company in cash; provided, however, that
         to the extent that the Withholding Amount is not provided by one or a
         combination of such methods, the Company in its sole and absolute
         discretion may refuse to issue such shares of Stock or may withhold
         from the shares of Stock delivered upon exercise of this Option that
         number of shares having a fair market value, on the date of exercise,
         sufficient to eliminate any deficiency in the Withholding Amount.

     16. NOTICE OF DISQUALIFYING DISPOSITION. If this Option is an incentive
         stock option, the Optionee agrees to notify the Company promptly in
         the event that he sells, transfers, exchanges or otherwise disposes of
         any shares of Stock issued upon exercise of the Option, before the
         later of (i) the second anniversary of the date of grant of the Option
         and (ii) the first anniversary of the date the shares were issues upon
         his exercise of the Option.

     17. TERMINATION OR AMENDMENT OF PLAN. The Board may in its sole and
         absolute discretion at ant time terminate or from time to time modify
         and amend the Plan, but no such termination or amendment will affect
         rights and obligations under this Option.

     18. EFFECT UPON EMPLOYMENT. Nothing in this Option or the Plan shall be
         construed to impose any obligation upon the Company to employ or
         retain in its employ, or continue its involvement with, the Optionee.

     19. TIME FOR ACCEPTANCE. Unless the Optionee shall evidence his or her
         acceptance of this Option by execution of this Agreement within seven
         (7) days after its delivery to him or her, the Option and this
         Agreement shall be null and void.

     20. General Provisions.

         (a) AMENDMENT; WAIVERS. This Agreement, including the Plan, contains
the full and complete understanding and agreement of the parties hereto as to
the subject matter hereof and may not be modified or amended, nor may any
provision hereof be waived, except by a further written agreement duly signed
by each of the parties. The waiver by either of the parties hereto of any
provision hereof in any instance shall not operate as a waiver of any other
provision hereof or in any other instance.

                                       4



     (b) BINDING EFFECT. This Agreement shall inure to the benefit of and be
binding upon the parties hereto and, to the extent provided herein and in the
Plan, their respective heirs, executors, administrators, representatives,
successors and assigns.

     (c) CONSTRUCTION. This Agreement is to be construed in accordance with the
terms of the Plan. In case of any conflict between the Plan and this Agreement,
the Plan shall control. The titles of the sections of this Agreement and of the
Plan are included for convenience only and shall not be construed as modifying
or affecting their provisions. The masculine gender shall include both sexes;
the singular shall include the plural and the plural the singular unless the
context otherwise requires.

     (d) GOVERNING LAW. This Agreement shall be governed by and construed and
enforced in accordance with the applicable laws of the United States of America
and the law (other than the law governing conflict of law questions) of The
Commonwealth of Massachusetts except to the extent the laws of any other
jurisdiction are mandatorily applicable.

     (e) NOTICES. Any notice in connection with this Agreement shall be deemed
to have been properly delivered if it is in writing and is delivered in hand or
sent by registered mail to the party addressed as follows, unless another
address has been substituted by notice so given:

                  To the Optionee:      To his or her address as
                                        listed on the books of the Company.

                  To the Company:       American Tower Systems Corporation
                                        116 Huntington Avenue
                                        Boston, MA  02116
                                        Attention:  Chief Financial Officer

                  and

                                        Sullivan & Worcester LLP
                                        One Post Office Square
                                        Boston, MA  02109
                                        Attention:  Norman A. Bikales



                                       5





                            Exhibit A to Stock Option

                       [FORM FOR EXERCISE OF STOCK OPTION

American Tower Systems Corporation
116 Huntington Avenue
Boston, Massachusetts 02116

    RE: EXERCISE OF OPTION UNDER AMERICAN TOWER SYSTEMS CORPORATION 1997 STOCK
        OPTION PLAN

Gentlemen:

     Please take notice that the undersigned hereby elects to exercise the stock
option granted to ___________ (the "Employee") pursuant and subject to the terms
and conditions of the Stock Option Agreement between the Employee and the
Company dated as of , 199 (the "Option Agreement") by and to the extent of
purchasing shares of [CLASS A OR CLASS B] Common Stock, par value $.01 per
share, of American Tower Systems Corporation (the "Company") for the option
price of $_____ per share.

     The undersigned encloses herewith payment, in cash or in such other
property as is permitted under the Plan of the purchase price for said shares.

     If the undersigned is making payment of any part of the purchase price by
delivery of shares of Common Stock of the Company, he or she hereby confirms
that he or she has investigated and considered the possible income tax
consequences to him or her of making such payments in that form. The undersigned
hereby agrees to provide the Company an amount sufficient to satisfy the
obligation of the Company to withhold certain taxes, as provided in Section 15
of the Option Agreement.

     The undersigned hereby specifically confirms to American Tower Systems
Corporation that he or she is acquiring said shares for investment and not with
a view to their sale or distribution, and that said shares shall be held subject
to all of the terms and conditions of said Stock Option Agreement.


                                       Very truly yours



                                       ----------------------------------------
                                       (Signed by the Employee or other
                                       party duly exercising option)





                            Exhibit B to Stock Option

           [FORM OF TERM NOTE IN PAYMENT OF EXERCISE PRICE OF OPTION]

                                 PROMISSORY NOTE

$                                           Date:
 -----------------------------------             ------------------------------

     FOR VALUE RECEIVED, the undersigned (the "Payor") hereby promises to pay to
the order of American Tower Systems Corporation (the "Payee") at the principal
office of Payee in Boston, Massachusetts ON DEMAND and in any event on or before
19 the sum of ($ ) with interest from the date hereof on the principal amount
hereof from time to time unpaid at the rate of ___ percent (___%) per annum.
Interest on the outstanding principal amount hereof shall be due and payable
monthly on the last business day of each month in each year during the term of
this Note, and at maturity commencing with the month end immediately following
the date of this Note. The Payor authorizes the Payee to withhold such interest
from his regular monthly or other salary payment or other compensation and to
apply such withheld amount to interest due hereon and also agrees to execute
such instruments and other documents as the Payee may from time to time request
to reflect such right of withholding. [THE PAYOR SHALL ON OF EACH YEAR,
COMMENCING IN , PAY AN AMOUNT EQUAL TO PERCENT ( %) OF THE ORIGINAL PRINCIPAL
AMOUNT OF THIS NOTE, TOGETHER WITH ALL ACCRUED AND UNPAID INTEREST THEREON.]

     All payments on this Note shall be first applied against accrued but unpaid
interest to the extent thereof, and then to the outstanding principal amount.

     The Payor shall have the right to prepay the principal amount of this Note
in whole or in part at any time without penalty, but together with all but
unpaid accrued interest on the outstanding principal amount. No such prepayment
shall affect the obligation of the Payor to make the payments required by the
last sentence of the first paragraph of this Note.

     Payor shall pay principal, interest, and other amounts under, and in
accordance with the terms of, this Note, free and clear of and without deduction
for any and all present and future taxes, levies, imposts, deductions, charges,
withholdings, and all liabilities with respect thereto, excluding taxes measured
by income.

     Should the indebtedness evidenced by this Note or any part thereof be
collected by legal action, or in bankruptcy, receivership or other court
proceedings, or should this Note be placed in the hands of attorneys for
collection after default, Payor agrees to pay, upon demand by Holder, in
addition to principal and interest and other sums, if any, due and payable
hereon, court costs and reasonable attorneys' fees and other reasonable
collection charges, to the maximum extent permitted by applicable law.

     This Note represents the obligation of the Payor to pay on an installment
basis the balance of the purchase price of shares of Common Stock of the Payee
to be issued to the Payor promptly after the date hereof (the "Shares"), plus
interest on such purchase price, pursuant to a stock option granted pursuant to
the Stock Option Agreement dated , 199 (the "Agreement").





     Upon the occurrence of any of the following events (an "acceleration
event"):

     (a) Failure of the Payor to perform or observe any of his obligations under
this Note or the Agreement, or acceleration of the payor's obligation to make
payment of the purchase price of the Shares pursuant to the provisions of the
Agreement; or

     (b) Commencement of voluntary or involuntary proceedings in respect of the
Payor under any federal or state bankruptcy, insolvency, receivership or other
similar law; or

     (c) Termination of the Payor's employment by the Payee; then, and in any
such event, the holder of this Note at its election may forthwith declare the
entire principal amount of this Note, together with accrued interest thereon,
immediately due and payable, and this Note shall thereupon forthwith become so
due and payable without presentation, protest or further demand or notice of any
kind, all of which are expressly waived.

     The Payor hereby waives the presentment, demand, notice of protest and all
other demands and notices in connection with delivery, acceptance, performance,
default or enforcement hereof. No delay or omission on the part of the holder of
this Note in exercising any right hereunder shall operate as a waiver of such
right or of any other right hereunder, no course of dealing between the Payor
and the holder shall operate as a waiver of any of the holder's rights hereunder
unless set forth in a writing signed by the holder, and a waiver on any one
occasion shall not be construed as a bar to or waiver of any right on any future
occasion. The Payor further agrees to pay the costs, fees and expenses
(including reasonable attorneys' fees) of collection and enforcement of this
Note.

     Any provision of this Note to the contrary notwithstanding, changes in or
additions to this Note may be made, or compliance with any term, covenant,
agreement, condition or provision set forth herein may be omitted or waived
(either generally or in a particular instance and either retroactively or
prospectively) with, but only with, the consent in writing of Holder and Payor,
and each such change, addition or waiver shall be binding upon each future
holder of the Note and Payor. Any consent may be given subject to satisfaction
of conditions stated therein.

     This Note shall be binding upon and shall inure to the benefit of the Payor
and the Payee and their respective successors and assigns, including, without
limitation, successors by operation of law pursuant to any merger, consolidation
or sale of assets involving any of the parties.

     This Note shall be deemed to be a contract made under and to be construed
in accordance with and governed by the applicable law of the United States of
America and the laws (other than the law governing conflict of law matters) of
The Commonwealth of Massachusetts.

     If the last or appointed day for taking of any action required or permitted
hereby (other than the payment of principal of or interest or premium, if any,
hereon) shall be a








Saturday, Sunday or legal holiday in Boston, Massachusetts, or a day on which
banking institutions in Boston, Massachusetts are authorized by law or executive
order to close, then such action may be taken on the next succeeding business
day for banking institutions in such city.

     This Note is executed as, and shall be effective as, a sealed instrument
and shall be binding upon the estate and any successor of the Payor.


Witness:
        ----------------------------        -----------------------------------
        Print Name:                         Print Name:






                            Exhibit C to Stock Option

                                ATTESTATION FORM

     Pursuant to the Notice of Exercise submitted herewith, I have elected to
purchase ________ shares of American Tower Systems Corporation (the "Company")
[Class A or Class B] Common Stock at $____ per share, as stated in the Stock
Option agreement dated __________. I hereby attest to ownership of the shares
under the certificate(s) listed below and hereby tender such shares in full or
partial payment of the total Option Price of $___________.

     I also certify that I either (i) have held the shares I am tendering for at
least one year after acquiring such shares through the exercise of an ISO, or
(ii) have not obtained such shares through the exercise of an ISO.

     Although the Company has not required me to make actual delivery of my
certificates, as a result of which I (and the joint owner, if any, of the shares
listed below) will retain ownership of the shares, I represent that I, with the
consent of the joint owner (if any) of the shares, have full power to deliver
and convey the certificates to the Company and therefore could have caused the
Company to become sole owner of the shares. The joint owner of the shares, by
signing this form, consents to the above representations and the exercise of the
stock option by this notice.



[Class A or Class B]       No. of Shares        Acquired by         Date of
    Common Stock            Represented        Stock Option       Acquisition
   Certificate(s)          Plan Exercise
                             (Yes/No)
                                                          
   -------------            -------------      -------------       -------------
   -------------            -------------      -------------       -------------
   -------------            -------------      -------------       -------------



     You are hereby instructed to apply toward the Option Price: (Check one)

     The maximum number of whole shares necessary to pay the Option Price, or,
if fewer, the total number of shares represented by the listed certificate(s),
with any remaining amount to be paid by check accompanying this Attestation
Form.

     _____________________ of the listed shares, with any remaining amount to be
 paid by check accompanying this Attestation Form.

     If I have paid only a portion of the total Option Price by tendering
Company [Class A or Class B] Common Stock, enclosed herewith is a check payable
to Company in the amount of $____________ for the balance of the Option Price.






                                                                   APPENDIX IV


 PROXY                                                  PROXY
CLASS A        AMERICAN TOWER CORPORATION              CLASS A
                  116 HUNTINGTON AVENUE
               BOSTON, MASSACHUSETTS 02116

 THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS

     The undersigned hereby appoints STEVEN B. DODGE, JOSEPH L. WINN and
JONATHAN R. BLACK, and each of them, as Proxies of the undersigned, each with
the power to appoint his substitute, and hereby authorizes a majority of
them, or any one if only one be present, to represent and to vote, as
designated below and on the reverse hereof, all the Class A Common Stock,
$.01 par value per share, of American Tower Corporation held of record by the
undersigned or with respect to which the undersigned is entitled to vote or
act at the 2001 Annual Meeting of Stockholders to be held on May 17, 2001 or
any adjournments thereof.

     THIS PROXY WHEN PROPERLY EXECUTED WILL BE VOTED IN THE MANNER DIRECTED
HEREIN BY THE UNDERSIGNED STOCKHOLDER(S). IF NO DIRECTIONS ARE MADE, THE
PROXIES WILL VOTE FOR EACH OF THE MATTERS LISTED ON THE REVERSE SIDE OF THIS
CARD AND, AT THEIR DISCRETION, ON ANY OTHER MATTER THAT MAY PROPERLY COME
BEFORE THE MEETING.



PLEASE VOTE, SIGN, DATE AND RETURN THIS PROXY CARD PROMPTLY
         USING THE ENCLOSED ENVELOPE.

(Continued and to be signed on reverse side.)




AMERICAN TOWER CORPORATION

CLASS A                  VOTE BY INTERNET                 CLASS A
               24 HOURS A DAY - 7 DAYS A WEEK
                  IT'S FAST AND CONVENIENT

              INTERNET   http://proxy.shareholder.com/amt

Use the Internet to vote your proxy. Have your proxy card in hand when you
access the website. You will be prompted to enter your control number,
located in the box below, to create an electronic ballot.

               MAIL

Mark, sign and date your proxy card and return it in the postage-paid
envelope we have provided.

Your Internet vote authorizes the named proxies to vote your shares in the
same manner as if you marked, signed and returned the proxy card.

If you have submitted your proxy by Internet there is no need for you to mail
back your proxy.

 PROXY CLASS A

       VOTE BY INTERNET http://proxy.shareholder.com/amt

___  CONTROL NUMBER FOR INTERNET VOTING

DETACH PROXY CARD HERE IF YOU ARE NOT VOTING BY INTERNET

CLASS A               AMERICAN TOWER CORPORATION               CLASS A



ELECTION OF DIRECTORS -          FOR ALL                     WITHHOLD AUTHORITY                          EXCEPTIONS*
                                                                                                
To elect eight (8) members       nominees listed below /X/   to vote for all nominees listed below /X/   as written below /X/
to the Board of Directors
of American Tower Corporation:

Nominees; 01 - Steven B. Dodge, 02 - Thomas H. Stoner, 03 - Arnold L.
Chavkin, 04 - Alan L. Box, 05 - Fred R. Lummis, 06 - J. Michael Gearon, Jr.,
07 - David W. Garrison and 08 - Maggie Wilderotter

(INSTRUCTIONS: TO WITHHOLD AUTHORITY TO VOTE FOR ANY INDIVIDUAL NOMINEE, MARK
THE "EXCEPTIONS" BOX AND WRITE THAT NOMINEE'S NAME IN THE SPACE PROVIDED
BELOW.)

*EXCEPTIONS
           -------------------------------------------------------------------



EVERGREEN AMENDMENT TO STOCK OPTION PLAN -
Amend the Stock Option Plan to provide for automatic annual increases in the
number of shares of Class A Common Stock authorized for issuance.

FOR /X/     AGAINST /X/      ABSTAIN /X/



3. RATIFICATION OF INDEPENDENT AUDITORS -
Ratification of Deloitte & Touche LLP as independent auditors for 2001

FOR /X/     AGAINST /X/      ABSTAIN /X/



TO TRANSACT SUCH OTHER BUSINESS AS MAY PROPERLY COME BEFORE THE ANNUAL
MEETING.

Please vote on our website at http://proxy.shareholder.com/amt
or sign, date and return this proxy in the enclosed prepaid
envelope. Please sign exactly as your name appears hereon
when signing in a representative capacity, please give full title.


DATED:           , 2001
      -----------

- -----------------------
SIGNATURE

- -----------------------
SIGNATURE


VOTES MUST BE INDICATED
(X) IN BLACK OR BLUE INK   /X/





 PROXY                                                  PROXY
CLASS B        AMERICAN TOWER CORPORATION              CLASS B
                  116 HUNTINGTON AVENUE
               BOSTON, MASSACHUSETTS 02116

 THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS

     The undersigned hereby appoints STEVEN B. DODGE, JOSEPH L. WINN and
JONATHAN R. BLACK, and each of them, as Proxies of the undersigned, each with
the power to appoint his substitute, and hereby authorizes a majority of
them, or any one if only one be present, to represent and to vote, as
designated below and on the reverse hereof, all the Class B Common Stock,
$.01 par value per share, of American Tower Corporation held of record by the
undersigned or with respect to which the undersigned is entitled to vote or
act at the 2001 Annual Meeting of Stockholders to be held on May 17, 2001 or
any adjournments thereof.

     THIS PROXY WHEN PROPERLY EXECUTED WILL BE VOTED IN THE MANNER DIRECTED
HEREIN BY THE UNDERSIGNED STOCKHOLDER(S). IF NO DIRECTIONS ARE MADE, THE
PROXIES WILL VOTE FOR EACH OF THE MATTERS LISTED ON THE REVERSE SIDE OF THIS
CARD AND, AT THEIR DISCRETION, ON ANY OTHER MATTER THAT MAY PROPERLY COME
BEFORE THE MEETING.



PLEASE VOTE, SIGN, DATE AND RETURN THIS PROXY CARD PROMPTLY
         USING THE ENCLOSED ENVELOPE.

(continued and to be signed on reverse side.)





AMERICAN TOWER CORPORATION

CLASS B                  VOTE BY INTERNET                  CLASS B
                 24 HOURS A DAY - 7 DAYS A WEEK
                    IT'S FAST AND CONVENIENT

              INTERNET   http://proxy.shareholder.com/amt

Use the Internet to vote your proxy. Have your proxy card in hand when you
access the website. You will be prompted to enter your control number,
located in the box below, to create an electronic ballot.

               MAIL

Mark, sign and date your proxy card and return it in the postage-paid
envelope we have provided.

Your Internet vote authorizes the named proxies to vote your shares in the
same manner as if you marked, signed and returned the proxy card.

If you have submitted your proxy by Internet there is no need for you to mail
back your proxy.

 PROXY CLASS A

       VOTE BY INTERNET http://proxy.shareholder.com/amt

____  CONTROL NUMBER FOR INTERNET VOTING

DETACH PROXY CARD HERE IF YOU ARE NOT VOTING BY INTERNET

CLASS B               AMERICAN TOWER CORPORATION               CLASS B



ELECTION OF DIRECTORS -          FOR ALL                     WITHHOLD AUTHORITY                          EXCEPTIONS*
                                                                                                
To elect six (6) members         nominees listed below /X/   to vote for all nominees listed below /X/   as written below /X/
to the Board of Directors
of American Tower Corporation:

Nominees; 01 - Steven B. Dodge, 02 - Thomas H. Stoner, 03 - Arnold L.
Chavkin, 04 - Alan L. Box, 05 - J. Michael Gearon, Jr., and 06 - David
Garrison.

(INSTRUCTIONS: TO WITHHOLD AUTHORITY TO VOTE FOR ANY INDIVIDUAL NOMINEE, MARK
THE "EXCEPTIONS" BOX AND WRITE THAT NOMINEE'S NAME IN THE SPACE PROVIDED
BELOW.)

*EXCEPTIONS
           -------------------------------------------------------------------



EVERGREEN AMENDMENT TO STOCK OPTION PLAN -
Amend the Stock Option Plan to provide for automatic annual increases in the
number of shares of Class A Common Stock authorized for issuance.

FOR /X/     AGAINST /X/      ABSTAIN /X/



3. RATIFICATION OF INDEPENDENT AUDITORS -
Ratification of Deloitte & Touche LLP as independent auditors for 2001

FOR /X/     AGAINST /X/      ABSTAIN /X/



TO TRANSACT SUCH OTHER BUSINESS AS MAY PROPERLY COME BEFORE THE ANNUAL
MEETING.

Please vote on our website at http://proxy.shareholder.com/amt
or sign, date and return this proxy in the enclosed prepaid
envelope. Please sign exactly as your name appears hereon
when signing in a representative capacity, please give full title.


DATED:           , 2001
      -----------

- -----------------------
SIGNATURE

- -----------------------
SIGNATURE


VOTES MUST BE INDICATED
(X) IN BLACK OR BLUE INK   /X/