During the opening days of World War II, the U.S. Army designated more than 18,000 square miles of the Arizona and California desert as a military training facility conceived by General George Patton and called the Desert Training Center, created to prepare troops for desert warfare in the invasion of North Africa. Operating from 1942 to 1944, it expanded beyond its original scope and became known as the California-Arizona Maneuver Area in 1943, with numerous camps, airfields, supply depots, hospitals, firing ranges, and maneuver areas established throughout the desert. Over the two-year life of the Desert Training Center, more than 1.2 million troops were hardened for battle in the deserts of California and Arizona. The archaeological remnants just north mark the camp site of the 36th Evacuation Hospital, which was stationed here for training from May to December 1943. Evacuation hospitals were 400-bed facilities that provided care to sick and wounded soldiers under combat conditions. The 36th remained at this site until it took part in IX Corps maneuvers and moved by Camp Dunlap near Niland, while maintaining a 100-bed base hospital here as the rest of the unit was deployed elsewhere. At the end of maneuvers, the entire hospital returned to this original site. The 36th Evacuation Hospital later served in the Pacific Theater of Operations, taking part in the New Guinea, Luzon, and Leyte Campaigns, the occupation of Japan, and service in Vietnam from 1966 to 1969.