33 Thomas Street

33 Thomas Street (also known as the AT&T Long Lines Building) is a 550-foot-tall (170 m) windowless skyscraper in the Tribeca neighborhood of Lower Manhattan in New York City, New York, United States. It stands on the east side of Church Street, between Thomas Street and Worth Street. Designed in the Brutalist architectural style, it is a telephone exchange or wire center building which contained three major 4ESS switches for interexchange carrier services (used for long distance calling), as well as a number of other switches used for competitive local exchange carrier services. However, it is not used for incumbent local exchange carrier services, and is not a central office. Its CLLI code is NYCMNYBW. It has been reported that the building is used as a National Security Agency (NSA) mass surveillance facility.

The location was previously the site of cast-iron buildings, typical of the area, the façades of which were removed for preservation before demolition. Construction of the building was started in 1969 and completed in 1974. The building was a core part of the AT&T Long Lines Department, housing solid-state switching equipment that required tight security and ample space. The Long Lines Department became AT&T Communications in 1984 after the breakup of the Bell System. The AT&T Long Lines Building is now commonly known by its street address, 33 Thomas Street. AT&T gradually moved switches and other facilities from their former AT&T Long Lines headquarters building at 32 Sixth Avenue, just a few blocks away, completing the move by 1999. 33 Thomas is still used for telephone switching, but some of the space is also used for highly secure datacenters. On September 17, 1991, management failure, power equipment failure, and human error combined to disable AT&T's central office switch at 33 Thomas. More than five million calls were blocked, and the Federal Aviation Administration private lines were also interrupted, disrupting air traffic control to 398 airports serving most of the northeastern United States. The problem arose when the electric utility, Consolidated Edison, asked AT&T to temporarily stop drawing electricity from the grid and instead use the b

Building data from Wikidata (CC0); heights normalised. Summary from Wikipedia (CC BY-SA).