World War II ended on Aug. 15, 1945 when Japan became the final member of the Axis powers to surrender. The war in Europe ended on May 8, 1945 when Germany surrendered.
Japan formally surrendered on Sept. 2, 1945. It signed a peace treaty in 1951. Germany was divided into East and West Germany after the war, but a treaty in 1990 reunited both sides.
The beginning of World War II is generally seen as Sept. 1, 1939, which is when Germany invaded Poland. The second Sino-Japanese War began on July 7, 1937, and the wars in Europe and the Pacific merged in 1941.