The Auschwitz concentration camp was the largest camp made by the Nazis. It had three main camps, all had prisoners at work. One of them also were used for a killing center.The SS created the three main camps near the city Oswiecim ,Auschwitz I in May 1940, Auschwitz II (Birkenau) in early 1942, and Auschwitz III (Monowitz) in October 1942. Auschwitz I , the main camp was the camp that held medical experiments and block 11. Block 11 was a block of severe torture. Auschwitz I also held the nazi staff that ran the entire camp complex. Auschwitz became the largest killing center for Jews during the holocaust. Also at auschwitz Dr. Josef Mengele was using young twins to use for experiments. These experiments happened in block 10 of auschwitz I.