In a few weeks of Blitzkrieg (lightning war), mechanized German divisions easily overwhelmed the ill-equipped Poles, taking western Poland. The Soviets seized the eastern part. In 1940 Germany swallowed Denmark, Norway, and the Low Countries and invaded France, which rapidly collapsed. With relish, Hitler forced the French to sign an armistice in the same train car where the Treaty of Versailles had been imposed on Germany 20 years earlier. Hitler then blockaded Britain and launched air raids and bomb attacks (see London Blitz). In 1941, to aid faltering Italian forces, he sent troops to North Africa, Greece, and Yugoslavia. Then he suddenly turned toward the east and invaded the USSR, breaking his nonaggression pact. As the Soviets retreated eastward, German armies engulfed the agriculturally rich Ukraine.

At this point, Hitler was master of continental Europe, although Britain was still resisting. In 1942 the United States entered the war after Japan’s attack on Pearl Harbor in Hawaii and dramatically increased its shipments of supplies and personnel to Britain and the USSR. Hitler then ordered total mobilization of people and resources. Throughout Europe, conquered peoples, especially Slavs and Jews, were executed or enslaved in German war factories, while occupied countries were drained of food and raw materials.