In the early 1970’s the United States began construction of a pyramid shaped building in a field in Nekoma, North Dakota. By 1975, the construction was complete, and the building was manned by military personnel.
The building was abandoned in 1976, after less than a year in operation.
The pyramid was part of the United States anti-ballistic missile project. Under the terms of the 1972 Anti-Ballistic Missile Treaty, the US was permitted to deploy a single ABM system protecting an area containing ICBM launchers. The complex provided launch and control for 30 LIM-49 Spartan anti-ballistic missiles, and 70 shorter-range Sprint anti-ballistic missiles.
Most of the missiles were held in underground silos at this location. The remaining were distributed at 4 remote locations within 20 miles.
The large circle in the center is the radar face, also known as the antennae array aperture. The small circle to the right of the radar face is the “Q” channel. The antennae atop the turret provided lightning protection for the building.
The taller towers are exhaust and the shorter ones are intake shafts. Diesel generators can also be seen.
This photo, taken early in the project on July 21st, 1971, highlights the massive amounts of rebar used in this project.
Taken on August 30, 1971, this image highlights the uncompleted subterranean portion. It also shows the workers, giving an idea of the massive scale of the structure.
The missile site control building turret on August 30, 1971.
The tunnel seen to the lower right of the photo was the escape tunnel. It would later be buried.
This photo from the interior of the structure displays the inspection fixture being installed on the antenna array support ring. This fixture was used to check the locations of the tapped holes through 36 shear key lugs.
The original design drawings, composed on January 1970 and revised January 2nd, 1974.
Construction on this complex began during an intense period of the Cold War with the goal of detecting and preventing any attack against the United States. Luckily not it, nor any of its brethren, were ever used. While weapons of mass destruction have only multiplied in force, reach, and capability, the threat of direct and unprovoked action against the United States dropped significantly shortly after the the Berlin Wall. These pictures serve to remind us of a time not long ago when the world sometimes teetered perilously on the edge of destruction.
H/T Wackulus[US Library of Congress]