Crown Castle International Corp., together with its subsidiaries, owns, operates, and leases shared wireless infrastructure in the United States and Australia. The company provides towers and other structures, such as rooftops; and distributed antenna systems, a type of small cell network (small cells). It provides access, including space or capacity to its towers, small cells, and third party land interests via long-term contracts in various forms, including license, sublease, and lease agreements. In addition, the company offers network services relating to wireless infrastructure, primarily consisting of antenna installations or subsequent augmentations, as well as site development services relating to wireless infrastructure. As of December 31, 2013, it owned, leased, or managed approximately 39,600 towers in the United States, including Puerto Rico; and approximately 1,700 towers in Australia. The company was founded in 1994 and is headquartered in Houston, Texas.