Allied air raids on industrial complexes in Germany necessitated the construction of underground production facilities. Camp prisoners dug huge tunnels into the surrounding mountains to house the production and storage areas. In 1943, prisoners at Dora-Mittelbau began construction of large underground factories and development facilities for the V-2 Missile program and other experimental weapons. These so-called "Weapons of Retaliation" were constructed and stored in the underground facilities and bomb-proof shafts.
Until the spring of 1944, prisoners were kept mostly underground, deprived of fresh air and daylight, and enclosed in unstable tunnels. The mortality rate was higher than at most other camps. Prisoners too weak or too ill to work there were sent to Auschwitz-Birkenau or Mauthausen to be murdered. In 1944, a compound to house forced laborers was built above ground level, south of the main factory area. Once full production of the missiles began in the fall of 1944, Dora-Mittelbau had a standing prisoner population of at least 12,000.
Dora-Mittelbau was enclosed by an electrified barbed-wire fence, with the main entrance located in the east part of the camp. To the west of the main entrance was the roll call area, where prisoners were assembled before they were marched off to forced labor. To the east, beyond the entrance, was the SS camp. The crematoria were located in the north part of the camp. The camp prison was located in the south part of the camp.
The Dora-Mittelbau was the center of a vast network of forced-labor camps built in 1944-1945 throughout the Harz Mountain region, including those located in nearby Niedersachswerfen, Nordhausen and Neusollstedt. Prisoners in the Dora-Mittelbau camp system quarried stone and worked on construction projects, munitions factories, the nearby ammonia works, and other projects related to weapons development and production.
Dora-Mittelbau had a prisoner resistance organization, which sought mainly to delay the production of the Weapons of Retaliation and to sabotage the rockets that were produced. Prisoners suspected of sabotage were usually killed, more than 200 were publicaly hanged for sabotaging production.
In early April of 1945, the Nazis began to evacuate prisoners from Dora-Mittelbau. Within days, most of the remaining prisoners were sent to Bergen-Belsen in northern Germany. Thousands were killed on death marches under horrendous conditions. When American forces liberated Dora-Mittelbau April 9, 1945, only a few prisoners were still in the camp.
