World War II history: the war that changed everything

World War II history begins with a conflict that pulled in nearly all of the world's countries and turned continents into battlefields. It became the deadliest conflict in history, with sixty to seventy-five million deaths, and its outcome reshaped international relations for decades.

How did World War II begin?

Most historians agree that World War II began with the German invasion of Poland on 1 September 1939. The war was a global conflict between the Allies and the Axis powers, and many countries took part in total war on an unprecedented scale.

The fighting did not stay in one region for long. In Europe, the struggle spread across borders and into occupied territory. In the Pacific, the conflict expanded after Japan's advances began to push across the region.

Why did the United States enter the war?

The United States entered the war against the Axis after Japan attacked Pearl Harbor in December 1941. That attack brought a major new power into the conflict and widened the war even further.

Japan's advances in the Pacific were halted at the Battle of Midway in June 1942. In early 1943, Axis forces were defeated in North Africa and at Stalingrad, two turning points that shifted the momentum of the war.

What were the major turning points in Europe and the Pacific?

The Western Allies invaded France at Normandy in 1944, opening a new front in Europe. That invasion added pressure on Germany from the west while the war continued elsewhere.

In Europe, the war concluded with Germany's unconditional surrender on 8 May 1945. In the Pacific, Japan announced its unconditional surrender on 15 August 1945 and signed a surrender document on 2 September 1945.

What did World War II change after the fighting stopped?

The Allied victory led to the occupation of Germany, Austria, Japan, and Korea. Those occupations were part of the new order that followed the war and helped define the postwar world.

World War II established the foundation of international relations for the rest of the twentieth century and into the twenty-first century. The United Nations was created to foster international cooperation and prevent future conflicts.

The Soviet Union and the United States emerged as rival superpowers, setting the stage for the Cold War. That rivalry grew out of a war that had involved almost every part of the globe and had been fought on an unprecedented scale.

World War II history is the story of a global conflict, a series of decisive battles, and a world that emerged from the war changed in lasting ways.

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