The Hollacaust was a genocide, or a mass killing, of Jewish people which was started by Hitler, the leader of the Nazis, in World War II. It was horrible event, and parts of it started maybe 2 or 3 years before WWII, but most people believe it only happened during World War II. Some people deny the existence of it, but it definitely did happen. Hitler's reasoning (By the way, Hitler is evil) was that the people of Germany needed a scapegoat, so he chose the Jewish people, who were peaceful and would not fight back. Mass numbers of the Jewish population died, and it was a truly horrifying event.