largely divided into the European Theater (Western Europe), Eastern Front, Mediterranean/North Africa Theater, and the Pacific Theater. During world war 2 between 22 and 26 million men were killed in battle as each side fought for their chosen cause.
How the war started Among the caues world war 2 were, to a greater extent, the political takeover in 1933 of Germany by Adolf Hitler and his Nazi Party and its aggressive foreign policy, and to a lesser extent, Italian Fascism in the 1920s, and Japanese militarism preceding an invasion of China in the 1930s.
After securing the neutrality of the Soviet Union through the August 1939 German-Soviet Pact of nonaggression Germany stared world war 2 by invading Poland on September 1, 1939. Britain and France responded by declaring war on Germany on September 3.