NORAD, headquartered in Colorado Springs, is the
bi-national U.S.-Canadian military organization responsible for the aerospace
and maritime defense of the United States and Canada. NORAD, created by a 1958 agreement between Canada and the United States, provides advanced warning of impending missile and air attacks against its member nations, safeguards the air sovereignty of North America, and maintains airborne forces for defense against attack. - Taken from NORAD Homepage.