On May 12, 1958, the North American Aerospace Defense Command (NORAD) was signed between the United States and Canada. It was founded as an effect of the Cold War.

The growing threat of long-range Soviet strategic bombers armed with nuclear weapons brought the U.S. and Canada into closer cooperation for air defense. While measures were in place to detect attacks from the Pacific or Atlantic, the Arctic was underprotected. In order to combat this threat, the U.S. and Canada agreed to construct a series of radar stations across North America to detect a Soviet attack over the Arctic. The first series of radars was the Pinetree Line, completed in 1954 and consisting of 33 stations across southern Canada. Several more radar stations were built in the following years. The stations were capable of giving three hours’ warning before a bomb could reach any major population center.

With the stations built, talks turned to who would take over the command and control of the system. Discussions and studies of joint systems had been ongoing since the early 1950s and in 1957 the U.S. and Canada announced a plan to establish a joint command of the stations, called the North American Air Defense Command. A formal NORAD agreement between the two governments was signed on May 12, 1958.

Today, NORAD still protects the northern border of the United States. It is probably most famous, however, for its annual tracking of Santa’s sleigh on Christmas.