The history of Arizona during World War II begins in 1940, when the United States government began constructing military bases within the state in preparation for war. Although far removed from the frontlines in Europe and the Pacific, Arizona's contribution to the Allied war effort was significant. Multiple prisoner of war camps and Japanese internment camps were established across the state, as well as several new airbases and associated sites, resulting in the birth of Arizona's aviation and manufacturing industries and the end of the Depression-era. The population of the state also experienced a major increase; many veterans returned to Arizona after the war ended in 1945, laying the foundations for the large metropolises of Phoenix and Tucson.