World war 2 started on 1st September 1939 and ended in 1945. It all started when Adolf Hitler, the leader of Germany, along with the Nazi party, decided they wanted to rule over Europe. During the war, countries made a pact to help each other. The two sides were called the Allies and the Axis. The Holocaust was one of the most terrible events to happen in history of the world, it happened during world war 2. There were many major battles in world war 2. After a long six years at war, the Allies won the war when Germany surrendered. However the war still went on in places such as USA and Japan. Japan finally surrendered on 2nd September 1945. This was when world war 2 officially ended for all countries.