A Cold War nuclear bunker is buried deep inside a Colorado mountain. See inside the Cheyenne Mountain Complex.

"The NORAD Cheyenne Mountain Complex dates back to the height of the Cold War. Initially meant for defense against long-range Soviet bombers, it now provides backup and training. The self-sufficient facility is sealed by 23-ton doors and built to withstand nuclear attacks."

"Buried 2,000 feet beneath Cheyenne Mountain is a secret military complex, where 15 buildings can seal themselves off from the rest of the world within seconds in the event of a nuclear blast. The complex is said to be designed to withstand a 30-megaton nuclear blast, per the Guardian, which is about 2,000 times as strong as the 15-kiloton bomb that was dropped on Hiroshima."

"Construction on the complex, which is located about 10 miles from downtown Colorado Springs, began in 1961. Today, the secretive underground complex remains functional as a backup command center for the North American Aerospace Defense Command (NORAD), a US-Canada binational organization that provides aerospace warning and control over North America, and the US Northern Command (USNORTHCOM)."

The Cheyenne Mountain Complex was constructed beginning in 1961 as a hardened Cold War installation near Colorado Springs. The facility sits about 2,000 feet underground and contains 15 buildings that can seal themselves within seconds behind massive 23-ton blast doors. The complex was engineered to survive very large nuclear detonations, reportedly up to a 30-megaton blast. The site originally focused on air defense against long-range Soviet bombers but now functions as a backup command center for NORAD and USNORTHCOM, providing aerospace warning, control, training, and continuity of operations for US and Canadian defense organizations.

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