Photos: Inside Cheyenne Mountain, America's Fortress

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.

This is the famous tunnel that leads into Cheyenne Mountain.

Photo by Daniel Terdiman/CNET

Caption by Daniel Terdiman