About World War 2

World War II, or the Second World War (often abbreviated as WWII or WW2), was a global military conflict lasting from 1939 to 1945 which involved most of the world's nations, including all of the great powers, organised into two opposing military alliances: the Allies and the Axis. It was the most widespread war in history, with more than 100 million military personnel mobilised. In a state of "total war," the major participants placed their entire economic, industrial, and scientific capabilities at the service of the war effort, erasing the distinction between civilian and military resources. Marked by significant action against civilians, including the Holocaust and the only use of nuclear weapons in warfare, it was the deadliest conflict in history.

The war is generally accepted to have begun on 1 September 1939, with the invasion of Poland by Nazi Germany and subsequent declarations of war on Germany by France and most of the countries of the British Empire and Commonwealth. China and Japan were already at war by this date, whereas other countries that were not initially involved joined the war later in response to events such as the German invasion of the Soviet Union and the Japanese attacks on the U.S. Pacific Fleet at Pearl Harbor and on British overseas colonies, which triggered declarations of war on Japan by the United States, the British Commonwealth, and the Netherlands.

The war ended with the total victory of the Allies over Germany and Japan in 1945. World War II left the political alignment and social structure of the world significantly changed. While the United Nations was established 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, which lasted for the next forty-six years. Meanwhile, the acceptance of the principle of self-determination accelerated decolonization movements in Asia and Africa, while Western Europe began moving toward economic recovery and increased political integration.