811 Tenth Avenue

811 Tenth Avenue is a windowless concrete tower standing 370 feet tall that occupies a full block between West 53rd and 54th Streets. The building was specifically designed to house telephone switching equipment and network infrastructure, with thick walls that keep it sealed off from the outside world.

The building opened in 1964 as an AT&T facility during Cold War tensions, when the United States wanted to protect critical communication systems from nuclear attack. Its fortress-like design reflects an era when keeping the telephone network safe and running was a matter of national concern.

Locals recognize this building as part of the hidden infrastructure that keeps the city running behind the scenes every day. It shows how critical communication hubs sit quietly between offices and theaters, serving the entire region without drawing attention to themselves.

The building is visible from the street and can be viewed from outside, though visitors cannot enter the interior. Its location in central Midtown Manhattan makes it easy to reach by public transportation.

After 1985, the NSA secretly used this building for extensive surveillance programs, making it central to national security operations. Few people who pass by daily realize the hidden role this plain-looking building played in intelligence history.