World War II began in 1939 and lasted until 1945. It involved many countries around the world, including Great Britain, France, the Soviet Union, the United States, China, Germany, Italy and Japan. Over 50 million people died in the war. Some of the key causes included the impact of the Great Depression, the Treaty of Versailles which handicapped Germany, and Japan's invasion of China to seek resources. The war resulted in the rise of the United States and Soviet Union as superpowers and weakened Western European influence globally. It also led to the emergence of the Cold War and beginning of the nuclear age.