American Tower Corporation (also referred to as American Tower or ATC) is an American publicly held company, owner and operator of wireless and broadcast communications infrastructure in several countries. American Tower is headquartered in Boston, Massachusetts and has local offices worldwide.[3] The company was formed in 1995 as a unit of American Radio Systems, and was spun off from that company in 1998 when that company merged with CBS Corporation. Following the merger, American Tower began international expansion by establishing operations in Mexico in 1998 and Brazil in 1999. The company is structured as a real estate investment trust and was named to Fortune magazine’s Fortune 500 for the first time in 2017. In 2005, American Tower merged with SpectraSite Communications, Inc., expanding its global portfolio to over 22,000 owned communications sites including over 21,000 wireless towers, 400 broadcast towers and 100 in-building DAS (Distributed Antenna System) sites. The merger further established American Tower’s position as one of the largest tower owner and operators in North America. Between 2007 and 2012, American Tower’s international growth continued with operations in India, Peru, Chile, Colombia, South Africa, Ghana and Uganda. In 2013, American Tower acquired its smaller rival Global Tower Partners for 4.8 billion. This acquisition added sites to their U.S. portfolio and added operations in Costa Rica and Panama. Currently American Tower owns and operates over 170,000 sites in 16 countries. Soon after American Tower was founded, the company began purchasing numerous AT&T Long Lines microwave telephone relay towers. Upon acquisition of these sites from the now defunct AT&T Communications, Inc., American Tower began repurposing the towers for use as cell towers, and leasing antenna space to various American cell phone providers and private industries. Then, most of the former AT&T Long Lines sites had their horn-reflector antennas removed, either by helicopter or by crane, to make room for more antennas. Since AT&T’s Long Lines Program was decommissioned in the 1980s, and the company no longer had any use for the towers themselves, American Tower now owns most of these tower structures across the entire continental United States. The picture below depicts a former AT&T Long Lines microwave radio relay tower, now repurposed by American Tower Corporation.