World War II, also called Second World War, conflict that involved virtually every part of the world during the years 1939–45. The principal belligerents were the Axis powers—Germany, Italy, and Japan—and the Allies—France, Great Britain, the United States, the Soviet Union, and, to a lesser extent, China. The war was in many respects a continuation, after an uneasy 20-year hiatus, of the disputes left unsettled by World War I. The 40,000,000–50,000,000 deaths incurred in World War II make it the bloodiest conflict, as well as the largest war, in history.
From September 3, 1939 To September 2, 1945
_Dwight D. Eisenhower.
_Charles de Gaulle.
_Franklin D. Roosevelt.
_Harry S. Truman.
About 70 million total soldiers fought on behalf of the Allied or Axis countries.
Switzerland, Spain, Portugal and Sweden all declared themselves neutral during WWII.
Some scholars argue that the “start” of WWII was in 1937 when Japan invaded China instead of when Germany invaded Poland.
Along with World War I, World War II was one of the great watersheds of 20th-century geopolitical history. It resulted in the extension of the Soviet Union’s power to nations of eastern Europe, enabled a communist movement to eventually achieve power in China, and marked the decisive shift of power in the world away from the states of western Europe and toward the United States and the Soviet Union.
John Graham Royde-Smith Dennis E. Showalter “World War II”، www.britannica.com