This facility is carved into the mountains of Colorado and is a military base that used to house NORAD (North American Aerospace Defence Command). Designed to withstand a nuclear attack, this facility keeps its eyes on the skies and is completely self-sufficient. In 2008, NORAD moved to the nearby Peterson Air Force Base, leaving a skeleton staff at Cheyenne. But it’s still operational, under strict secrecy.

Oddly enough it’s got a Level One security designation, which makes this base more secure than the Pentagon.