Only 20 years after the commitment to the treaty, on 1 September 1939, the nations were thrust into the depths of World War II, and the disaster had unraveled to become the most destructive war in history with Hitler's tenacity and notable supremacy. The war was fought between two groups of countries, the Allied Powers and the Axis Powers.
The major Allied Powers: Britain, France, Russia, China, and the United States.
The major Axis Powers: Germany, Italy, and Japan.
However, some other countries also remained neutral in World War II, such as Spain, Sweden, and Switzerland who chose not to join either side.