Auschwitz concentration camp was a complex of over 40 concentration and extermination camps operated by Nazi Germany during World War II and the Holocaust. It included Auschwitz I, the main camp, Auschwitz II-Birkenau, which was both a concentration and extermination camp, and Auschwitz III-Monowitz, a labor camp, along with dozens of subcamps. These camps became central to the Nazis' Final Solution, where at least 1.1 million people were exterminated. The liberation of Auschwitz by the Soviet Union on January 27, 1945, revealed the horrors of the Holocaust to the world.