World War 2 was a global war that lasted from 1939 to 1945. World War 2 was a major war and the U.S. did not want to be part of it. But after the attack in Pearl Harbor, the U.S. had no choice but to declare war on the Axis team, which was composed by Germany, Italy, Japan, Hungary, Romania, and Bulgaria. The United States were part of the Allies team, composed of Great Britain, France, USSR (Russia), Australia, Belgium, Brazil, Canada, China, Denmark, Greece, Netherlands, New Zealand, Norway, Poland, South Africa, and Yugoslavia. The U.S. had 10 million people in the war, and atlas we won in 1945 when the Axis team surrendered.