A thousand feet up a restricted-access road from Colorado Springs, Colo., is Cheyenne Mountain. Long thought of interchangeably with NORAD, the North American Aerospace Defense Command, Cheyenne Mountain actually houses elements of NORAD, as well as many other U.S. government defense-related agencies, including Air Force Space Command, U.S. Strategic Command, the National Security Agency and more.
Situated under 2,000 feet of rubble, Cheyenne Mountain--which, contrary to popular belief, is still fully functional--was designed to house critical government and defense functions in case of a nuclear strike. To this day, its infrastructure is meant to protect the interior of the installation against just about any kind of attack.
This is the famous tunnel that leads into Cheyenne Mountain.