Compound BIIf at Birkenau, Auschwitz II, was one of the worst sections of the entire camp. The area was used as a Haftlingskrankenbau (prisoner infirmary), from July 1943 until January 1945, when the camp was eventually liberated by Soviet troops. Inmates of the camp called the area the "crematoria waiting room", due to the fact that most of the prisoners held in this particular compound were destined for the crematoria. In addition to horrific experiments conducted by SS doctors such as the infamous Josef Mengele, selections were also undertaken at this part of the camp, with those chosen sent to their deaths in one of the four gas chambers located nearby. Block 1 was used as an administrative block for the SS, a pharmacy and also an office for the camp's SS doctors. It is here, that Josef Mengele conducted much of his work.