During what years did WWII occur?

World War II started in 1939 and ended in 1945. The United States joined the war in 1941 after the Japanese navy bombed Pearl Harbor.

The war began with Germany’s invasion of Poland in 1939. Italy and Japan later joined Germany, and the three nations were known as the Axis. The Soviet Union joined Great Britain and France to form the Allies, who were later joined by the United States. Major turning points of the war included the invasion of Normandy in 1944 and the dropping of atomic bombs on Japan in 1945. More than 40 million casualties were reported in the six-year conflict that ended with the surrender of Axis forces in 1945.