The killing area and the crematoria are located in these basement rooms.

Whilst at first the dead were burned in the municipal crematoria in Steyr and Linz, in 1940 the camp’s first incinerator went into operation. A second oven was added in 1942 and a third in 1945, shortly before liberation. The SS also had incinerators installed in the Gusen branch camp and the Melk and Ebensee subcamps.

These crematoria were used by the SS not only to dispose of the corpses, but also to eliminate the traces of violence and neglect visible on those corpses. Separate prisoner work detachments were responsible for burning the corpses. They were housed in this basement, isolated from the rest of the camp.

Starting in 1941, facilities for mass killing were installed here: an execution room with an apparatus for shooting people in the back of the neck and a gallows. In early 1942, the SS began to operate a gas chamber. Up to May 1945, at least 3,500 prisoners were killed in it using the poison gas Zyklon B. After 1945, none of the SS men accused of committing crimes in the Mauthausen concentration camp ever tried to deny the existence of the gas chamber at Mauthausen or the murder of people in it.