The life expectancy of prisoners was as short as six months, and at least 35,000 people died there from forced labor, starvation, and mass executions.

Prisoners were forced to construct vast underground factories, the main one being the Bergkristall [de; es], intended for the production of Messerschmitt Me 262 jet fighter aircraft.

[3] The site of Mauthausen concentration camp was chosen in May 1938 by an SS delegation including Theodor Eicke and Oswald Pohl.

The location was chosen for the quarries around the villages of Mauthausen and Sankt Georgen an der Gusen, leased by the SS enterprise DEST.

[16][13][8] The camp was directly adjacent to the road between Sankt Georgen an der Gusen and nearby Langenstein;[17][10] former prisoners recalled Austrian children passing by on the way to school.

[22] Prisoners faced starvation rations, forced labor, and beatings by guards and kapos, while being denied basic sanitary facilities.

[19] Often drunk,[11] he personally beat, kicked, whipped, and killed prisoners;[25] he had considerable autonomy in running the camp and ensured that life was characterized by violence and sadism.

A third fence, of barbed wire, was added to encircle the entire camp complex, including external factories and quarries.

[29] SS physician Helmuth Vetter, who arrived in 1944, conducted the tuberculosis experiments by injecting the lungs of healthy prisoners with phlegmonic pus.

[33][13] At the brothel ten women, all considered "Aryan", were coerced into offering sex in exchange for a false promise of their freedom.

[17] Either Chmielewski[38] or SS-Hauptscharführer Heinz Jentsch [pl][17] invented a new execution method called Totbaden (death baths).

Prisoners unable to work and others the SS wanted to kill were forced to stand under cold showers until they died, which could take twenty minutes to two hours.

Despite being targeted for excessive punishment by the SS guards—sixty percent died by the end of 1941, mostly in the quarries—the Spanish prisoners gained a reputation for solidarity.

[35] From 1943,[13] the purpose of the camp was switched from quarrying to armaments production in vast underground factories, to protect the industrial output from Allied bombing.

[57] Other prisoners produced rifles, machine guns, and airplane motors for Steyr-Daimler-Puch AG in 16 large warehouses northeast of the original Gusen camp.

[22][43] In the tunnels, prisoners were supervised by Messerschmitt employees (engineers, foremen and skilled workers) who were forbidden to discuss the project with anyone on pain of death.

The space was to serve as an underground factory for Messerschmitt Me 262 jet fighter aircraft, sufficient to produce 1,250 fuselages per month[58][59] along with the entire slat production necessary.

[23] Gusen II, which opened on 9 March, was close to the main camp, separated only by a potato field, and also located on the St. Georgen road.

[61] Gusen III was 8 kilometres (5.0 mi) north, near Lungitz; its 260 prisoners worked in a nearby brick factory and in manufacturing parts for Messerschmitt, in barracks rather than tunnels.

[13][26] About 4,000 Warsaw Uprising prisoners were sent to Gusen in late 1944 and additional inmates arrived due to the evacuation of concentration camps in early 1945 as Allied armies approached.

Overcrowding meant that there were three people to a bunk, and conditions were even worse in Block 31, where those suffering from dysentery were thrown on the floor and denied food.

More SS left the camp in groups on 3 May 1945, with the pretext of fighting the Soviet army, although most, in fact, hid in the surrounding woods and hills.

[23][72][73] Staff Sergeant Albert J. Kosiek, in charge of a platoon in the 41st Cavalry Squadron, was ordered to investigate a suspected enemy strongpoint near Mauthausen, and to check the bridge near Gusen which was intended to be used by American tanks.

North of St. Georgen, Kosiek encountered a Red Cross representative who told him that there was a concentration camp at Mauthausen and 400 SS who wanted to surrender.

Many of the sickest prisoners had been sealed in barracks without food or water; when the American soldiers opened them it was rare to find more than one or two still alive.

[80] On 8 May, Nazi Party members were ordered to bury the dead in the potato field between Gusen I and II while local citizens were forced to watch.

[23] Former kapo Rudolf Fiegl was convicted, sentenced to death, and hanged for gassing prisoners,[31] as was the SS doctor Vetter.

[23][38] Jentsch, involved in the "death baths", was arrested in West Germany, tried in Hagen in 1967, convicted, and sentenced to life in prison.

[85][87] In the 2010s, local municipalities around Mauthausen and Gusen set up a Bewußtseinsregion ("consciousness region") in order to promote preservation and restoration of the sites.

[88] In late 2019 and early 2020, the Polish government suggested that the Gusen village should be bought and additional efforts made to commemorate the victims of the camp.