Tuesday, May 21, 2013
A look back
From its early days in the 1960s, NORAD has monitored air activities around the nation and the world from inside Cheyenne Mountain. Beyond the rock-walled tunnel leading to the entrance doors is a city built on more than a thousand springs weighing 1,000 pounds each. The steel springs, three inches in diameter, are designed to help cushion the buildings that sit atop them in a nuclear blast or earthquake.
