The North American Air Defense Command (NORAD) was established and activated at the Ent Air Force Base on September 12, 1957. This command is a bi-national organization, of Canadian and United States Air Defense Command units, in accordance with NORAD Agreements first made on May 12, 1958. In the late 1950s, a plan was developed to construct a command and control center in a hardened facility as a Cold War defensive strategy against long-range Soviet bombers, ballistic missiles, and a nuclear attack.