San Juan Hill, United States. The windowless slab of 33 Thomas Street in Manhattan is a 550 foot tall telephone switching center, the largest in the city, and among the largest in the world. It was built by AT and T in 1974, as its new Long Lines (long-distance) hub. It is still a telco switching center, though it now houses equipment for Verizon, as well as AT and T. It is also a major data center.