The European Theater

German Aggression

The war in Europe began in September 1939, when Germany, under Chancellor Adolf Hitler, invaded Poland. Britain and France responded by declaring war on Germany but took little action over the following months. In the spring of 1940, Germany launched the next phase of its program of territorial expansion with attacks on Denmark and Norway, followed shortly thereafter by attacks on Belgium, the Netherlands, and France. All of these nations were conquered rapidly. In the summer, Germany launched a further attack, on Britain, this time exclusively from the air. The Battle of Britain was Germany’s first military failure, as the German air force, the Luftwaffe, was unable to overcome Britain’s Royal Air Force. 

The Mediterranean

In the late summer and fall of 1940, German’s ally Italy broadened the geographic scale of the war even further, first by attempting to increases its territorial holdings in North Africa and then by invading Greece. Initial success against British forces in the Horn of Africa was followed by failure against British forces in Egypt. In 1941, Germany reluctantly sent troops to Africa in support of Italy. The campaign in Greece was also a failure; there, too, Germany was forced to come to Italy’s aid. 

The USSR

Later in 1941, Germany began its most ambitious action yet, by invading the Soviet Union. Although the Germans initially made swift progress and advanced deep into the Russian heartland, the invasion of the USSR would prove disastrous for Germany. Although Russia initially responded with only poorly coordinated resistance, it soon began inflicting heavy losses on the invaders. Russia’s brutal winters also worked to the German army’s disadvantage. In 1943, after the battles of Stalingrad and Kursk, Germany was forced into a full-scale retreat. During the course of 1944, the Germans were slowly but steadily forced completely out of Soviet territory, after which the Russians pursued them across eastern Europe and into Germany itself in 1945.

The Normandy Invasion

In June 1944, British and American forces launched the D-Day invasion, entering German-occupied France via the coast of Normandy. Soon the German army was forced into retreat from that side, as well. Thus, by early 1945, Allied forces were closing in on Germany from both east and west. The Soviets were the first to reach the German capital of Berlin, and Germany surrendered in May 1945, shortly after the suicide of Adolf Hitler.

The Pacific Theater

Early Engagements

On December 7, 1941, warplanes from Japan launched a surprise attack on the U.S. Navy base at Pearl Harbor, Hawaii. By this time, Japan had already been at war with China for several years and had seized the Chinese territory of Manchuria. After the Pearl Harbor attack, Japan began a massive campaign of expansion throughout the Southeast Asia–Pacific region, posing a long-term threat not just to American interests but to also British, Dutch, French, Soviet and Australian interests. Beginning in late spring of 1942, the United States engaged Japan in a series of naval battles, climaxing in the Battle of Midway on June 3–6, 1942, which ended catastrophically for the Japanese. 

Japan’s Defeat

Between August 1942 and February 1943, Allied forces carried out a long series of offensives that would eventually drive Japanese forces off all the territory they had seized earlier. By the late spring of 1945, most of Japan’s conquests had been liberated, and Allied forces were closing in on the Japanese home islands. As they neared Japan proper, the Allies began heavy bombing campaigns against major Japanese cities, including Tokyo. This process continued through the summer of 1945 until finally, in early August, the United States dropped two atomic bombs on the cities of Hiroshima and Nagasaki. Stunned by the unexpected devastation, Japan surrendered a few days later.