On September 1, 1939, at 4:45 a.m. in the morning, 1.5 million German troops invaded Poland along its1,750-mile border with German-controlled territory. The German Luftwaffe bombed Polish airfields, and German warships and U-boats attacked the Polish navy in the Baltic. Nazi leader Adolf Hitler claimed the massive invasion was a defensive action. Thus began World War II. The U.S. would keep its head buried in the sand for several years until the Japanese bombing of Pearl Harbor. . .
Just about every country that fought in World War I also fought in World War II. This was a World War, ranging from Europe/Russia to Tunisia in North Africa, China, South East Asia and the Pacific Islands. Some say the war started with Hitler's march on Prague in March, 1939, or the Japanese invasion of China in 1937, or even the Japanese invasion of Manchuria in 1931. Maybe it was when Adolf pulled the wool over Josef 's eyes and they agreed to the secret Hitler-Stalin Pact. Wasn't that what emboldened Hitler to make a move in the first place. Eventually, of course, Hitler made war on Stalin too. . .
 The cause of the war is often thought to be the Treaty of Versailles, the Great Depression, and most of all, nationalism. In the end, every cause of the war can be classed as ambition or madness.