Although the Fallout universe and the real world share a common timeline until about 1945, the defining moment of the Fallout universe was the Great War of 2077. On October 23, 2077, the United States, China, and other nuclear-armed countries commenced a brief but rapid exchange of nuclear strikes. Although the conflict lasted only two hours, the destruction it brought was staggering and complete: more energy was released in the early moments of the war than in all previous global conflicts combined.