The Holocaust is one of the most known genocides in history. It was all started by the leader, Adolf Hitler. The Nazis that came to power in Germany believed that Germans were "racially superior" and the Jews were "inferior" or alien to the German community. The Nazis didn't just attack the Jews though. They also went after Roma (Gypsies), the disabled, and some of the Slavic peoples (Poles, Russians, and others). Others were persecuted on political, ideological, and behavioral grounds, among them Communists, Socialists, Jehovah's Witnesses, and homosexuals. Over 400,000 people were killed because they were either Roma or mentally and physically disabled. As for the political and ideological opponents, they created concentration camps for them and to monitor the Jews. The SS guards moved the camp inmates by going on "death marches" to prevent the Allied liberation of large numbers of prisoners. This went on until May 7, 1945 when the German forces surrendered to the Allies.