What were the historical, political, and economic factors that led to the Holocaust?

I can give one for each, WWI influenced Europe very much so and even the ideals of Hitler, and I'd say the political movements at the time that influenced Germany would the German Revolution, where the German Monarchy was replaced for a parliamentary system, which was later replaced by Hitlers socialist government. An economic factor would have been just been the overall ruin the German economy was after WWI.