Totalitarian governments like those of Hitler, Stalin, and Mussolini are discussed. Hitler invades Poland in 1939 starting WWII. Within a year, Germany conquers much of Western Europe while Britain withstands the Luftwaffe bombing campaign. In 1941, Germany invades the Soviet Union and makes large gains initially. Japan attacks Pearl Harbor in 1941 bringing the US into the war against the Axis powers. With help from allies like the Soviet Union and US, the Allies gain victories over German and Japanese forces in several key battles. Germany surrenders in 1945 after the atomic bombs are dropped on Hiroshima and Nagasaki, ending WWII.