On September 1, 1939, Germany invaded Poland and World War II began. This is when Adolf Hitler came to power. During his reign he tried to exterminate all the Jewish people. The Nazis saw the Jews as enemies of the German people, so they persecuted them relentlessly. They firmly believed that the Jews wanted to rule the world and that for this reason they did not deserve a living space of their own (Nazi ideology and victims of the Holocaust and Nazi persecution). One of the ways he did this was through the use of the numerous concentration camps scattered throughout German-occupied Europe. During the war he had millions of people held prisoner in these camps. When we think of the Holocaust, we generally also think of these concentration camps where so many Jews were forced to live. However, other types of people besides Jews were kept in the camps. This was because Germany had used the camps before the war to hold those they considered undesirable. Nonetheless, all the people in the camps had to face the horrible treatment. The first camp began operating in March 1933, but by the end of the Second World War the Germans had more than 4,000 across Europe (Daily life in the concentration camps). From 1933 to 1945 Germany had a total of around 20,000 operational camps. Jews in places under Nazi control were the first to be taken to the camps. They were used for a wide variety of purposes, such as forced labor camps, transit camps (where prisoners were only held temporarily), and extermination camps built only to kill. Prisoners were taken from their homes and usually passed through several camps before arriving at the extermination camp, which would be the final destination of most prisoners. Depth." 2014. United States Holocaust Memorial Museum. March 18, 2014 "Daily Life in the Concentration Camps." 2014. United States Holocaust Memorial Museum. March 18, 2014 "Forced Labor in the Holocaust: context and overview." 2014. Jewish Virtual Library. March 20, 2014. "Nazi Ideology and Holocaust Victims and Nazi Persecution." 2014. United States Holocaust Memorial Museum. March 19, 2014. Segev, Tom. Soldiers of Evil. . New York: McGraw-Hill Book Company, 1987.