World War 2

Europe

On September 1, 1939, Germany, led by Adolf Hitler and the Nazi Party, invaded Poland according to a secret agreement with the Soviet Union, which joined the invasion on September 17. The United Kingdom and France responded by declaring war on Germany on September 3, initiating a widespread naval war. Germany rapidly overwhelmed Poland, then Norway, the Netherlands, Belgium and France in 1940, and Yugoslavia and Greece in 1941. Italian, and later German, troops attacked British forces in North Africa. By summer 1941, Germany had conquered France and most of Western Europe, but it had failed to subdue the United Kingdom due to the success of the Royal Air Force and Royal Navy.

Hitler then turned on the Soviet Union, opening a surprise attack (Codename: Barbarossa) on June 22, 1941. Despite enormous gains, the invasion bogged down outside of Moscow in late 1941. The Soviets later encircled and captured the German Sixth Army at the Battle of Stalingrad (1942-43), decisively defeated the Axis during the Battle of Kursk, and broke the Siege of Leningrad. The Red Army then pursued the retreating Wehrmacht all the way to Berlin, and won the street-by-street Battle of Berlin, as Hitler committed suicide in his underground bunker on April 30, 1945.

Meanwhile, the western Allies invaded Italy (1943) and then liberated France in 1944, following amphibious landings in the Battle of Normandy. Repulsing a German counterattack at the Battle of the Bulge in December, the Allies crossed the Rhine River and linked up with the Soviets at the Elbe River in central Germany.

Asia and the Pacific

Main article: Pacific War

Japan invaded China on July 7, 1937 (see Second Sino-Japanese war) with plans to expand to most of East and South-East Asia. On December 7, 1941 Japan launched surprise attacks against several countries, including the major United States Navy base at Pearl Harbor, thereby drawing the United States into the war.

After six months of sweeping successes, the Japanese were checked at the Battle of the Coral Sea and decisively defeated in the Battle of Midway, in which they lost four aircraft carriers. Japanese expansion was finally stopped and the Allies went on the offensive at the Battle of Milne Bay and the Battle of Guadalcanal, both in the Southwest Pacific. The Allies then conducted a drive across the Central Pacific, and were victorious in a series of great naval battles such as the Battle of the Philippine Sea and the Battle of Leyte Gulf in 1944, and invasions of key islands such as Iwo Jima and Okinawa in 1945. In the meantime, American submarines gradually cut off the supply of oil and other raw materials to Japan.

In the last year of the war Allied air forces conducted a strategic firebombing campaign against the Japanese homeland. On August 6, 1945, the U.S. dropped an atomic bomb on the Japanese city of Hiroshima, and on August 9 another was dropped on Nagasaki. Japan surrendered on August 15, 1945.

Aftermath

About 62 million people, or 2.5% of the world population, died in the war, though estimates vary greatly (refer to the Casualties section). Large swaths of Europe and Asia were devastated and took years to recover. The war had political and technological consequences that last to this day.

Causes

Benito Mussolini of Fascist Italy (left) and Adolf Hitler of Nazi Germany.Main articles: Causes of World War II, Events preceding World War II in Europe, and Events preceding World War II in Asia

The general causes commonly believed to have lead to WWII are the rise of nationalism, the rise of militarism, and the presence of unresolved territorial issues. Fascist movements emerged in Italy and Germany during the global economic instability of the 1920s, and consolidated power during the Great Depression of the 1930s. In Germany, resentment of the Treaty of Versailles Ð'-- specifically article 231 (the "Guilt Clause"), the belief in the Dolchstosslegende, and the onset of the Great Depression fueled the rise to power of the militarist National Socialist German Workers Party (the Nazi party), of which Adolf Hitler