World War 2

World War II or the Second World War was a global conflict that began on 7 July 1937, in Asia and 1 September 1939, in Europe and lasted until 1945, involving the majority of the world's countries and every inhabited continent. Virtually all countries that participated in World War I were involved in World War II. It was the most extensive and expensive apocalyptic armed conflict in the history of the World.

Attributed in varying degrees to the Treaty of Versailles, the Great Depression, nationalism, and militarism, the causes of the war are a matter of debate. On which date the war began is also debated, cited as either the German invasion of Poland on 1 September 1939, the Japanese invasion of China on 7 July 1937 (the start of the Second Sino-Japanese War), or earlier yet the 1931 Japanese invasion of Manchuria. Still others argue that the two world wars are one conflict separated only by a "ceasefire".

Fighting occurred across the Atlantic Ocean, in Western and Eastern Europe, in the Mediterranean Sea, Africa, the Middle East, in the Pacific and South East Asia, and it continued in China. In Europe, the war ended with the surrender of Germany on 8 May 1945 (V-E and Victory Days), but continued in Asia until Japan surrendered on 15 August 1945 (V-J Day).

Approximately 57 million people died as a result of the war, including acts of genocide such as the Holocaust, the Rape of Nanking, and General Ishii Shiro's Unit 731 experiments in Pingfan. As a case of total war, it involved the "home front" and bombing of civilians to a new degree. Atomic weapons, jet aircraft, and RADAR are only a few of many war-time inventions.

Post-war Europe was partitioned into Western and Soviet spheres of influence, the former undergoing economic reconstruction under the Marshall Plan and the latter becoming satellite states of the Soviet Union. Western Europe largely aligned as NATO, and Eastern Europe largely as the Warsaw pact, alliances which were fundamental to the ensuing Cold War. In Asia, the United States' military occupation of Japan led to its democratization, and China came to split into the Communist People's Republic of China and the Nationalist Republic of China.