Germany quickly overran the Polish and turned north. Denmark and Norway were easily defeated in 1940, and the German army turned west, invading Belgium and the Netherlands. German forces successfully surrounded and destroyed the British Army at Dunkirk and forced the French to surrender.
After the fall of France, Italy joined the war, and the British fleet was trapped in the Mediterranean, when German Paratroopers seized Gibraltar and the Italians overran Egypt, capturing the Suez and cutting off the British supply lines to Africa.
The next year German forces launched Operation Barbarossa and invaded the Union of Soviet Socialist Republics. The disorganized and demoralized Red Army was easily destroyed and the nation collapsed, with Germany taking all the land up to the Urals and dividing it into several Reichskommisariats: Ostland, Ukraine, Moskowien, and Kaukasus.
Around this time, the Empire of Japan attacked the Americans in Pearl Harbor, bringing the US into the war. Within a year England had been conquered, and Europe was completely under Nazi Domination. In 1944, a German plane launched from a Japanese carrier conducted a nuclear strike on Pearl Harbor, the first of its kind in history. The Americans soon signed an armistice and the war ended.