What do you know already about the Holocaust?

Out of what I know of the Holocaust I just know that German Nazi's who were followers of Hitler killed a bunch of Jews because of Hitler. They hated Jews for no reason. But during the Holocaust, many Jews were put in concentration or death camps, which are basically the same thing. They both killed a bunch of people in different unique ways. They even experimented on the people with science experiments that usually ended up with the results of them dying. They also raped the women, and tortured the men. I also know a famous pianist who was a Jew that suffered during the Holocaust who survived. I believe his name was Horowitz. A famous pianist who I also like. When it ended with the victory of the alliance against the axis, all the Germans were judged, but they had a major problem because everything about war was a crime, so it was hard for them to judge. For they all deserved to die, which especially Soviet Union hated when osme of them were left alive, because they suffered the most during the war efforts. The holocaust was basically a period of massacre towards the jews.