World War II (1939–45) was the largest and most destructive conflict in history. Fifty million people died during the war; millions of others were wounded or driven from their homes. Two opposing factions battled around the world for global supremacy. Great Britain and France led the Allied Powers until 1941, when they were joined by the Soviet Union and the United States. The Axis Powers were led by Germany, Italy, and Japan. The stakes of World War II were huge. The very existence of free, tolerant, and democratic nations was threatened, as were the lives of millions.