The Holocaust, was the mass murder or genocide of approximately six million European Jewish people during World War 2, a program of systematic state-sponsored murder by Germany, led by Adolf Hitler and the Nazi Party, throughout German-occupied territory. Of the nine million Jews who had resided in Europe before the Holocaust, approximately two-thirds were killed. Over one million Jewish children were killed in the Holocaust, as were approximately two million Jewish women and three million Jewish men. During the era of the Holocaust, German authorities also targeted other groups because of their perceived "racial inferiority". Other groups were persecuted on political, ideological, and behavioral grounds, among them Communists, Socialists, Jehovah's Witnesses, and homosexuals. They made them wear a yellow Star of David patch on their chests' so that they could be identified.