On September 17, Soviet troops invaded Poland from the east. Under attack from both sides, Poland fell quickly. At sea, however, the British and German navies faced off in heated battle, and lethal German U-boat submarines struck at merchant shipping bound for Britain, sinking more than 100 vessels in the first four months of World War II.
On April 9, 1940, Germany simultaneously invaded Norway and occupied Denmark, and the war began. On May 10, German forces swept through Belgium and the Netherlands in what became known as “blitzkrieg,” or lightning war. Three days later, Hitler’s troops crossed the Meuse River and struck French forces at Sedan, located at the northern end of the Maginot Line. Benito Mussolini of Italy put his Pact of Steel with Hitler into action, and Italy declared war against France and Britain on June 10. On June 14, German forces entered Paris.
German planes bombed Britain extensively throughout the summer of 1940, including night raids on London and other industrial centers that caused heavy civilian casualties and damage. The Royal Air Force (RAF) eventually defeated the Luftwaffe (German Air Force) in the Battle of Britain, and Hitler postponed his plans to invade. With Britain’s defensive resources pushed to the limit, Prime Minister Winston Churchill began receiving crucial aid from the U.S. under the Lend-Lease Act, passed by Congress in early 1941.
By early 1941, Hungary, Romania and Bulgaria had joined the Axis, and German troops overran Yugoslavia and Greece that April. The other half of Hitler’s strategy was the extermination of the Jews from throughout German-occupied Europe. Plans for the “Final Solution” were introduced around the time of the Soviet offensive, and over the next three years more than 4 million Jews would perish in the death camps established in occupied Poland.
On June 22, 1941, Hitler ordered the invasion of the Soviet Union. Though Soviet tanks and aircraft greatly outnumbered the Germans’, their air technology was largely obsolete, and the impact of the surprise invasion helped Germans get within 200 miles of Moscow by mid-July. Arguments between Hitler and his commanders delayed the next German advance until October, when it was stalled by a Soviet counteroffensive and the onset of harsh winter weather.
World War II in the Pacific (1941-43)
With Britain facing Germany in Europe, the United States was the only nation capable of combating Japanese aggression, which by late 1941 included an expansion of its ongoing war with China and the seizure of European colonial holdings in the Far East. On December 7, 1941, 360 Japanese aircraft attacked the major U.S. naval base at Pearl Harbor in Hawaii, taking the Americans completely by surprise and claiming the lives of more than 2,300 troops. The attack on Pearl Harbor served to unify American public opinion in favor of entering World War II, and on December 8 Congress declared war on Japan with only one dissenting vote. Germany and the other Axis Powers promptly declared war on the United States.
After a long string of Japanese victories, the U.S. Pacific Fleet won the Battle of Midway in June 1942, which proved to be a turning point in the war. On Guadalcanal, one of the southern Solomon Islands, the Allies also had success against Japanese forces in a series of battles from August 1942 to February 1943, helping turn the tide further in the Pacific. In mid-1943, Allied naval forces began an aggressive counterattack against Japan, involving a series of amphibious assaults on key Japanese-held islands in the Pacific. This “island-hopping” strategy proved successful, and Allied forces moved closer to their ultimate goal of invading the Japanese homeland.
Toward Allied Victory in World War II (1943-45)
In North Africa, British and American forces had defeated the Italians and Germans by 1943. An Allied invasion of Sicily and Italy followed, and Mussolini’s government fell in July 1943, though Allied fighting against the Germans in Italy would continue until 1945.
On World War II’s Eastern Front, a Soviet counteroffensive launched in November 1942 ended the bloody Battle of Stalingrad, which had seen some of the fiercest combat of the war. The approach of winter, along with dwindling food and medical supplies, spelled the end for German troops there, and the last of them surrendered on January 31, 1943.
On June 6, 1944–celebrated as “D-Day”–the Allies began a massive invasion of Europe, landing 156,000 British, Canadian and American soldiers on the beaches of Normandy, France. In response, Hitler poured all the remaining strength of his army into Western Europe, ensuring Germany’s defeat in the east. Soviet troops soon advanced into Poland, Czechoslovakia, Hungary and Romania, while Hitler gathered his forces to drive the Americans and British back from Germany in the Battle of the Bulge (December 1944-January 1945), the last major German offensive of the war.