THE 21st CENTURY
'(<a href="http://www.j-archive.com/media/2007-06-28_J_07.jpg" target="_blank">Jon of the Clue Crew reports from Cheyenne Mountain.</a>) Since the end of the Cold War, the only emergency closing of these 25-ton blast doors at NORAD's Cheyenne Mountain complex was on this 21st-century date'
September 11, 2001