• The antennae that mark the 9,560-foot summit of Cheyenne Mountain have nothing to do with missile-warning operations. They are relay towers for area radio and television stations.
• Utah Mining & Engineering Co. excavated for 16 months to carve out more than 693,000 tons of granite, most of which was dumped into the canyon to build a parking lot.
• The blast doors inside the mountain are 3 feet thick, weigh 25 tons each and take from 30 to 40 seconds to close. They were closed on Sept. 11, 2001.
• The mountain interior is studded with 115,000 bolts, ranging from 6 to 32 feet in length, that reinforce the rock to prevent collapse.
• There is one escape hatch that stretches 50 feet through rock into the main tunnel. When the blast doors malfunctioned during an exercise in 1979, the NORAD commander had to take the emergency route to get to his next appointment.
• The natural temperature inside the mountain is a constant 58 degrees. But there's no need for a furnace: the heat generated by computers is enough to warm up the offices.
• An underground artesian spring discovered during excavation of the mountain caused flooding problems at first. Now it provides a steady supply of fresh drinking water, stored in an underground reservoir.
• Cheyenne Mountain's unique fire-escape system uses remote-controlled floor lighting to guide people on their knees through smoky hallways to safety.
• Electrical carts are used inside the mountain to cut down on carbon dioxide emissions. Only the shuttle bus crew and top commanders can drive vehicles with combustion engines.
Source: North American Aerospace Defense Command