World War II started on September 1, 1939, when Nazi Germany, under Adolf Hitler, invaded Poland. The war ended on September 2, 1945, with the formal surrender of Japan. The conflict lasted just over six years and involved most parts of the world, with major combatants split between the Axis powers (Germany, Italy, and Japan) and the Allies (including France, Great Britain, the United States, and the Soviet Union).
Key dates:
- Start: September 1, 1939 (Germany invades Poland)
- End: September 2, 1945 (Japan surrenders)
The war's escalation included the US entering after Japan's attack on Pearl Harbor on December 7, 1941, and the Axis powers being defeated by 1945, with Nazi Germany surrendering in May and Japan in August 1945.
