[American Tower Corporation Letterhead]


FOR IMMEDIATE RELEASE

ATC Contact:  Anne Alter, Director of Investor Relations
Telephone:  (617) 375-7500
UNIsite Contact:  Grace Vista, Marketing Manager
Telephone:(813) 915-3511

AMERICAN TOWER CORPORATION ANNOUNCES MERGER WITH UNISITE, INC.

Boston,  Massachusetts  June 28, 1999 American  Tower  Corporation  (NYSE:  AMT)
announced  today that it has entered into an  agreement  to merge with  UNIsite,
Inc.

The cash  transaction is estimated to be valued at  approximately  $205 million,
which is based on UNIsite owning and operating 600 wireless communication towers
at the time of closing.  The purchase  price will be subject to  adjustment  for
closing  date  working  capital  and  includes  American  Towers  assumption  of
approximately   $40  million  of  debt,   subject  to  adjustment   for  interim
acquisitions and capital  expenditures,  and $165 million in cash. The merger is
expected to close by January 31, 2000.

UNIsite was founded in 1994 to address the  challenges  associated  with antenna
siting and to focus  primarily  on tower site  management.  Most  recently,  the
company has expanded its scope to include site  ownership and  development.  The
Company now owns  approximately  400 towers  suited for  co-location  and has an
exclusive build-to-suit contract with Omnipoint through the year 2012.

Jim  Eisenstein,  Chief  Development  Officer  of  American  Tower,  said of the
transaction,  We are very pleased to have  entered  into a merger with  UNIsite.
This  transaction not only adds an attractive  group of towers to our portfolio,
particularly  in the  northeast,  but also gives us an opportunity to expand our
relationship with a number of carriers.

Dan Behuniak,  President of UNIsite,  remarked, re excited to become part of the
American Tower team. As the industry consolidates further,  American Tower, with
its talented management team and financial strength, is clearly slated to be one
of the best places to be.

American  Tower is a  leading  independent  owner,  operator  and  developer  of
broadcast and wireless  communications  sites in the United  States and,  giving
effect to this and other pending transactions,  operates more than 4,000 towers,
including 185 broadcast  tower sites, in 44 states and the District of Columbia.
Based in Boston,  American Tower has a national  footprint with regional hubs in
Boston, Atlanta,  Chicago,  Houston and San Francisco.  Through its wholly owned
subsidiary,  ATC Teleports,  Inc., American Tower also owns and operates, giving
effect to pending transactions,  over 90 satellite antennas in various locations
across the United States.  For more information about American Tower Corporation
and    ATC    Teleports,     please    visit    our    web    sites    HYPERLINK
http://www.americantower.com www.americantower.com and www.atcteleports.com.

This  press  release  contains  forward-looking   statements  concerning  future
expectations,   plans  or  strategies   that  involve  a  number  of  risks  and
uncertainties.  The Company wishes to caution  readers that certain  factors may
have  affected  the  Company's  actual  results  and  could  cause  results  for
subsequent   periods  to  differ   materially   from  those   expressed  in  any
forward-looking  statement  made by or on behalf of the  Company.  Such  factors
include,  but  are not  limited  to (i)  substantial  capital  requirements  and
leverage   principally  as  a  consequence  of  its  ongoing   acquisitions  and
construction activities,  (ii) dependence on demand for wireless communications,
use of satellites for internet data transmission,  and implementation of digital
television,  (iii) the success of the Company's tower  construction  program and
(iv)  the  successful   operational   integration  of  the  Company  s  business
acquisitions.  The Company  undertakes no  obligation to update  forward-looking
statements to reflect subsequently occurring events or circumstances.

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American Tower Corporation    116 Huntington Avenue  Boston, Massachusetts 02116
(617) 375-7500  FAX (617) 375-7575                         www.americantower.com