One Colorado destination that has inspired a slew of legends over the years, the Cheyenne Mountain Complex in Colorado Springs, Colorado is a military installation in a peculiar place. Instead of simply being built on Cheyenne Mountain, the complex was built inside of it over a 5 year period from 1961 to 1966.
The base has been used for a variety of purposes, including housing the North American Aerospace Defense Command (NORAD) operations until 2008, as well as housing certain Federal Emergency Management (FEMA) tasks. The base also doubles as a nuclear bunker.
One of the most secure bases in the country, the complex is found under 2,000 feet of granite, spanning approximately 5 acres. It utilize a giant spring system to protect more than a dozen three story buildings from any movement caused by earthquakes or explosions. This complex is also able to withstand an electromagnetic pulse (EMP), making it the only high altitude Department of Defense facility able to do so.
The sturdy construction of this facility means that it’s able to withstand a 30 megaton nuclear explosion at a distance as close as 1.2 miles, in part thanks to 25-ton blast doors. To put that in perspective, the most powerful bomb ever detonated by the United State had a yield of 15 megatons during a test.