World War II began in September 1939 when Germany invaded Poland, prompting Britain and France to declare war on Germany. The war ended in September 1945. Key events included Hitler annexing Austria in 1938, the non-aggression pact between Nazi Germany and the Soviet Union in 1939, Britain's failed appeasement policy toward Germany, and Germany's use of blitzkrieg tactics involving air power and fast-moving ground forces to quickly defeat opponents. The major powers aligned in the war were the Axis powers of Germany, Italy, and Japan against the Allied powers including Britain, France, the Soviet Union, China, and the United States.