The main camp Auschwitz-I belonged next to the extermination camp Auschwitz-II Birkenau and Auschwitz III-Monowitz camp complex of Auschwitz and was one of the major German concentration camps. It was between May 1940 and January 1945, after the occupation of Poland in the annexed Polish territory of the German now named the district Bielsko on the southwestern edge of the town also renamed Auschwitz (Polish: Oswiecim).

Parts of the camp are now state-owned Polish museum or memorial. Since June 27, 2007, a total carries most of the former concentration camp Auschwitz in the list of UNESCO World Heritage Site, the official name "Auschwitz-Birkenau - German Nazi Concentration and Extermination Camp". The SS internal acronym in the era of National Socialism was Auschwitz (KL = concentration camps). The numbering of parts warehouse has been used mainly in the postwar period a clear distinction between the three different parts of the Auschwitz concentration camp. At times they were within the administration, the abbreviation for the three main camp.

source: http://de.wikipedia.org/wiki/KZ_Auschwitz_I_(Stammlager)