Why was the Cheyenne Mountain complex built near Colorado Springs?

The Cheyenne Mountain complex was constructed near Colorado Springs to serve as a hardened, secure command and control installation for the North American Aerospace Defense Command (NORAD).12

During the Cold War, military strategists recognized the extreme vulnerability of critical command centers to nuclear attack. To ensure the continuity of operations and the ability to provide early warning of hostile bombers or missiles, engineers designed a vast facility embedded deep within the granite of Cheyenne Mountain. By housing the operations center inside this mountain, the military created a fortified structure capable of resisting the blast and shock effects of a nuclear detonation, thereby protecting the vital systems used to track aerospace threats and coordinate defense units.123