American Tower Corporation is a holding company. The company owns, operates and develops wireless and broadcast communications real estate. Its primary business is leasing antenna space on multi-tenant communications sites to wireless service providers, radio and television broadcast companies, wireless data and data providers, government agencies and municipalities. The Company conducts operations through its subsidiaries and joint ventures. Its principal operating subsidiaries are American Towers LLC and SpectraSite Communications, LLC. The Company offers tower-related services domestically, including site acquisition, zoning and permitting services and structural analysis services, which primarily support site leasing business and the addition of new tenants and equipment on its sites. The Company is a real estate investment trust (REIT). It operates in three segments: domestic rental and management, international rental and management and network development services.