Yuma is one of the oldest cities in the southwest United States. MCAS Yuma was established in 1928. During World War II in 1943, an air base was erected with the astounding speed which characterized the war effort. The base became one of the busiest flying schools in the nation. At the end of the war, all flight activity here ceased and the area was partially reclaimed by the desert. On July 7, 1951, the Air Force reactivated the base, and the 4750th Air Base Squadron resumed training as part of the Western Air Defense Forces. Yuma's Primary mission is to support aerial weapons training for the Atlantic and Pacific Fleet Marine Forces and Navy, and to serve as a base of operations for Marine Aviation Weapons and Tactics Squadron-1 and Third MAW units.