World War II was a global conflict fought mainly between the Allies and the Axis from 1 September 1939 to 2 September 1945. It is generally considered to have begun when Germany invaded Poland, prompting Britain and France to declare war.
The conflict became the deadliest in human history, causing an estimated 60 to 75 million deaths through combat, genocide, massacres, starvation, and disease. Millions were murdered in genocides, including the Holocaust.
The war’s roots lay in the unresolved consequences of World War I, the rise of aggressive dictatorships, and expansionist ambitions in Europe and Asia. Germany rapidly expanded across Europe and invaded the Soviet Union in June 1941. In Asia and the Pacific, Japan had already been waging war in China and in December 1941 attacked Pearl Harbor and other Allied territories, bringing the United States fully into the war.
By 1942–1943, Axis advances began to stall. Important turning points included Midway in the Pacific, Stalingrad on the Eastern Front, and Allied victories in North Africa. The Allies then advanced on multiple fronts, invading Italy in 1943, landing in Normandy in 1944, and pushing into Germany while Soviet forces advanced from the east. In the Pacific, the United States and its allies steadily rolled back Japanese control. Germany surrendered on 7–8 May 1945, and Japan surrendered on 15 August 1945, formally signing the surrender on 2 September 1945 after the atomic bombings of Hiroshima and Nagasaki and the Soviet invasion of Manchuria.
Aftermath
The war reshaped the modern world. Germany and Austria were occupied, Germany was divided into East and West Germany, and the United Nations was founded in October 1945. The wartime alliance between the Western powers and the Soviet Union collapsed into the Cold War, while Korea was divided, the Chinese Civil War resumed, and weakened European empires increasingly gave way to decolonisation.