World War II. World War II — History.com Articles, Video, Pictures and Facts. World War II. World War II (WWII or WW2), also known as the Second World War, was a global war that lasted from 1939 to 1945, though related conflicts began earlier.
It involved the vast majority of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis. It was the most widespread war in history, and directly involved more than 100 million people from over 30 countries. In a state of "total war", the major participants threw their entire economic, industrial and scientific capabilities behind the war effort, erasing the distinction between civilian and military resources. World War II altered the political alignment and social structure of the world.
The United Nations (UN) was established to foster international co-operation and prevent future conflicts. WWII. WWII. WWII.