Camps in Germany included Dachau, Bergen-Belsen, and Buchenwald; camps elsewhere in Europe included Auschwitz-Birkenau in German occupied Poland and Mauthausen in Austria among the numerous other concentration camps, and death camps handled with the utmost of secrecy. The extermination camps' function was genocide; they included Treblinka, Bełżec, and Sobibór built specifically for Aktion Reinhard, as well as the original Chełmno extermination camp, and Majdanek which was fitted with mass killing facilities, along with Auschwitz. They were responsible for facilitating what the Nazis called the Final Solution, known since the war as the Holocaust;[4] perpetrated by the SS within the command structure of the Reich Main Security Office, subordinate to Heinrich Himmler, and the SS Economic and Administrative Main Office or WVHA.[5]