Hitler’s Germany enjoyed a run of success during the early years of the Second World War. Having defeated Poland, on 9 April 1940 Hitler turned to the invasion of Scandinavia and there forced Denmark into surrender in only a matter of hours. On 10 June, Norway capitulated.
In 1940, the war turned to the Low Countries. Both Belgium and the Netherlands capitulated as the Germans swept through northern France, brushing aside the French army. The British army, sent as reinforcements, was pushed back to the port of Dunkirk and forced into a frantic evacuation back to Britain. France fell in June 1940. Only Britain remained to fight the Germans. Hitler planned to invade England but needed control of the skies above southern England as a prelude to a full-blown attack. However, the RAF kept the Luftwaffe at bay during the Battle of Britain and cities throughout the country survived the Blitz to the point Hitler postponed his plans for invasion indefinitely.
In June 1940, Mussolini entered the war and attacked Greece and then Libya, but was soon forced into retreat. Hitler sent forces to aid the situation, conquering Greece, Crete and also Yugoslavia, and committing to a long struggle in North Africa. In June 1941, Hitler launched Operation Barbarossa – the invasion of the Soviet Union, less than two years after the signing of the Non-Aggression Pact and its agreement of ten years of peace. The German advance through Russia was spectacular. But with their lines of communication stretched the further they advanced, and with the weather turning against them, the German juggernaut ground to a halt only fifteen miles short of Moscow.
On 7 December 1941, the Japanese attacked Pearl Harbor, bringing the US into the war. Four days later, Hitler declared war on America. The war was now truly a global conflict.