The war in Europe began on September 1, 1939 with the invasion of Poland by Nazi Germany, and concluded on September 2, 1945, with the official surrender of the last Axis nation, Japan. However, in Asia the war began earlier with Japanese interventions in China, and in Europe, the war ended earlier with the unconditional surrender of Germany on May 8, 1945.
The conflict spilled over into Africa, included a handful of incidents in the Americas, and a series of major naval battles.
It was the largest armed conflict in history, spanning the entire world and involving more countries than any other war, as well as introducing powerful new weapons, culminating in the first use of nuclear weapons.
