The Holocaust was Hitler's mass murder of over six million Jews and other inferior races. He also thought that he should rid his nation of any people that had any physical or mental handicaps. The word Holocaust actually means a sacrificial offering of something that is completely burned.
After the war had started, in 1939, Germany was conquering one country after another. Hitler then began to start capturing the Jews. He killed many of them and sent others to concentration camps where they would soon be killed after being crucially tortured by the Nazis. In 1941, Hitler and his Nazi leadership called for the "Final Solution to the Jewish Question." This called for the persecution of every man, woman, or child that was of the Jewish race in Germany. After the outbreak of World War II, Hitler established death camps to secretly implement this policy. Extermination squads were also sent to the fronts. In one operation alone, over 30,000 Jews were killed at Babi Yar, outside Kiev. After 450,000 Jews were sent to death camps from the Warsaw Ghetto, news of their fate led the last 60,000 to rebel (1943), fighting until they were killed, captured, or escaped to join the resistance. The main Jewish resistance was spiritual: observing their religion and refraining from suicide.
By the fall of 1941, the Nazis had already begun to exterminate all of the mentally and physically challenged people in Germany. They killed some Jews at this time but sent most of them to Eastern Europe and Russia, where they would later be dealt with in the same manner of the rest of them. Hitler used a type of euthanasia program. The German doctors would kill any of the people with these "defects." Hitler wanted to perfect the human race. He wanted the Germans to be the superior race. Most of these people were killed by carbon monoxide gas that was stored in large bottles at concentration camps, but others were killed in gas vans.