While relocating the aviation industry to numerous new locations, the Germans also started constructing better-protected factories. There were two types of such factories: underground factories and bunker factories, some of which were constructed partially under- ground. The main difference between normal dispersal and dispersal to underground and bunker factories should be clear. Normal dispersal schemes sought to relocate existing plants to new places, where basic production halls and other facilities already existed or could be easily constructed within a short time. As was already mentioned, firms were empowered to confiscate every facility they considered suitable for their relocation plan. In contrast, relocation to underground facilities or to other kinds of protected plant usually meant a large construction project, either in order to create the required facility or to adapt it for its new role. The amount of construction involved in this type of relocation was a crucial element. It demanded a large workforce for the excavation and construction. It also required massive cement castings and other heavy-duty construction. These characteristics made these construction sites extremely suitable for slave workers under SS custody. Furthermore, it meant that production in this type of plant could not commence a short time after the relocation; it usually took several months before these factories were ready. Some of them were never finished before war’s end.
Immediately after the war Willy Messerschmitt boasted to his American interrogators that he sought to place his factory underground as early as 1935, and that these initiatives received no support.284 This claim is probably an exaggeration, like other exaggerations
made by Messerschmitt in his interviews, but by the late 1930s the fear of strategic air attacks brought the first notions of placing key facilities underground. After the war some BMW executives told the Americans that in 1937, when the firm planned its new aero- engine plants, BMW’s engineering group pointed out to the RLM the dangers of bombing raids and suggested placing the factories entirely underground in converted salt mines or alternately in a forest near Munich. These factories were intended to serve mainly as “shadow” factories, to be used only in case of war in order to expand production. Eventually it was decided to construct the new factory in the Allach Forest, not far from the firm’s main factory in Munich.285When the Germans conquered France in 1940 they were surprised to
find an underground aircraft factory at Creil near Paris, where light bombers of the firm Lioré et Olivier were produced.286 It is possible that this discovery, as well as a survey of
another plant of engine manufacturer Gnôme et Rhône near Paris, influenced BMW’s gen- eral director Franz Josef Popp. In November 1940 he submitted to the RLM a memo in which he discussed the advantages of windowless hardened factories compared to under- ground factories.287
The RLM took no action after receiving Popp’s memo.
The Germans first gained experience with giant fortified structures while constructing concrete submarine pens along the French Atlantic coast in 1941–1942. These bunkers orig- inally had a reinforced concrete roof of between 3.5 and 7.5 meters thick, but later in the war additional layers of concrete were added to many of them.288Factories were not fortified
at this stage, but curiously the first documented move of an aircraft factory to an under- ground facility occurred on the French Atlantic coast. The managers of the SNCASO firm in Bordeaux, being an important subcontractor of Focke-Wulf at that time, feared Allied bombings already in 1942 and sought to move some parts of their main factory to a chalk caves system in a hillside near St. Astier. It seems that this move was also viewed as an opportunity to ease congestion in the main factory and to expand its capacity. Excavations and further tunneling in the caves began in late 1942 and the floor of the first cave was ready by July 1943. The initiative was fortunate, because the USAAF heavily bombed the Bordeaux factory on 17 May 1943. Only one cave with a floor area of 147,828 square meters was used. In order to improve working conditions for the workers, a canteen was also constructed in the cave and offered the workers low-priced hot meals. Focke-Wulf planned an eventual monthly output of 400 rear fuselage and tail units for the FW 190 fighter in this factory. Delays caused by sabotage and by the uncooperative attitude of the firm’s French manage- ment, among others causes, severely hampered production in the St. Astier factory. Never- theless, even as late as July 1944 — after D-Day — Focke-Wulf and the Jägerstab sought to enlarge the cave, bring in more machine tools, and start a two-shift daily schedule in order to make full use of the capacity of this factory. Achieving this goal proved to be very difficult due to French partisans operating in the area and the generally difficult supply and trans- portation situation.289By the time of the liberation, the St. Astier factory produced only 20
tail units. After the war it was found out that the factory was getting enough fresh air and that a constant temperature of 12° Celsius was maintained inside the caves without artificial assistance. Furthermore, “it was stated that the chalk dust had no adverse effect on the mov- ing parts of machine tools.”290
The Germans started contemplating constructing bombproof factories following the first wave of American daylight raids on aviation-related factories in early 1943. On 11 April, Hitler demanded during a meeting with Speer and other armaments officials to prepare the relocation of the production of some key items, like crankshafts and bevel wheels, to fortified factories.291Following this conference the RLM assigned a civil engineer named Bilfinger
to head a special staff and recommend the best way to protect the existing factories. Bilfinger’s
Sonderstab Höhlen-Bau (Special Staff Caves-Construction) was composed of engineers, geol-
ogists and construction experts. Its initial recommendation was to encase important factories in concrete bunkers. This scheme was totally unrealistic due to the amount of work and resources required in order to complete it, and it was not pursued further.
It is assumed that the first concrete initiative to move vital factories to a protected underground facility came after the RAF and the USAAF bombed several factories associated with the V-2/A-4 missile production in June and August 1943. The production of this missile was supposed to be carried out in 3 main centers. The first was the highly secret
Peenemünde complex, where the A-4 and the Fi 103 (V-1) were developed and tested, and where the prototype series of the A-4 was already produced. The second factory was the Henschel-owned Rax Works in Wiener-Neustadt, Austria. It was an old locomotive factory, now converted into a missile factory. The third center was the old Zeppelin Luftschiff bau factory in Friedrichshafen, which once constructed airships and now produced radar antennas and other light metal products. The RAF attacked the Zeppelin factory on the night of 21– 22 June 1943. The factory was targeted because the British received intelligence indicating that it produced radar equipment. The USAAF attacked the Rax factory on 13 August 1943 because it was thought to be a Me 109 factory. These attacks unintentionally hit at the heart of the V-2 production even before it started. The third strike, however, was fully intentional and was based on precise information gathered by British intelligence. On the night of 17–18 August 1943, the RAF heavily attacked the V-2 development center at Peenemünde. The attack missed the most important facilities, but it shocked the German establishment, which was sure until then that the base was safe.292On the day after the attack Speer suggested to Hitler
to move the entire ballistic missile project underground. Hitler agreed and ordered the allocation of the required manpower for the construction work from Himmler’s concentration camps reservoir.293Soon afterwards Special Committee A-4 chose an underground fuel storage facility
in the Harz Mountains, near Nordhausen and Niedersachswerfen as the site of the main A- 4 production plant. Construction of the missile plant began under the direction of Dr. Hans Kammler, an engineer and a rising star in the SS hierarchy. The SS cooperated closely in the construction of the factory with the Wirtschaftliche Forschungsgesellschaft (WIFO), which was originally responsible for the site.294This underground plant was largely completed
by the end of 1943 and became infamous as the Mittelbau-Dora, or the Mittelwerk complex. The Mittelbau-Dora project set the stage for later similar projects. The SS became deeply involved in it right from the beginning mainly because it was the only agency able to provide the required manpower for its construction. The entire project relied on SS-sup- plied manpower, and all this manpower came from the concentration camps reservoir. Himmler initially based his growing involvement in the V-2 production on the premises that the SS would be in a better position to protect the V-2 facilities if it became more involved in the program. In this regard slave labor seemed to offer an excellent solution to several security problems.295The relocation of the V-2 program to a single massive under-
ground facility was the first of its kind in Germany during World War II. It was done after other measures to avoid bombings — like dispersal and camouflage — seemed to fail. It was a total solution, driven mainly by the shock caused by the bombing of Peenemünde and other production centers within a short time period, but it was a sign for the type of reaction expected in similar cases of Allied action.
In autumn 1943 Hitler and Speer also discussed the move of certain other factories to bombproof underground locations. The aviation industry figured prominently in the fol- lowing discussions. On 2 October 1943 Xaver Dorsch, the head of Organisation Todt, offered to build for Göring a giant underground factory, capable of producing 500 fighters or 200 bombers monthly as an alternative to the “Ultra” above-ground factory. The output of this factory was obviously far from “Ultra’s” projected “thousand bombers” goal, but it was better protected. Dorsch was consulted earlier about the construction of “Ultra” and saw here an opportunity to broaden the responsibilities of his organization.296
Furthermore, due to earlier allocations of responsibilities, the OT was allowed to operate only in the occupied
countries and not on the Reich’s territory. Construction projects inside the Reich were man- aged by the Construction Office of the Armaments Ministry or by the military. Construction of bombproof aircraft factories therefore offered Dorsch the opportunity to operate his organization inside the Reich.297
Several days after Dorsch’s offer, Göring, who became espe- cially concerned for the safety of aircraft production following recent damage caused by daylight bombing, wrote to Speer and pointed out the urgent need to protect his factories. He suggested allocating the highest priority to the aero-engine industry and to factories producing other bottleneck items. These factories were supposed to relocate to existing underground facilities, like tunnels, mines, etc., and if these were not available, Göring asked to encase the crucial factories in concrete.298Preparations for the move of some of the
most important aero-engine production began soon afterwards, and Bilfinger’s staff, now bearing the title Cave Commissioner (Höhlenoberkommissar), was ordered to prepare pre- liminary surveys of possible underground locations.299
At this point BMW and Junkers stood at the focal point of the scheme. According to Junkers executives interrogated by USSBS teams after the war, the firm drew plans to move engine production underground already in early 1943.300However, during a visit to Junkers
in Dessau at the beginning of November 1943 Göring expressed again his intention to move the most important aviation factories underground. First to go were several aero-engine production lines, including Junkers’ own modern engine production, as well as BMW’s Allach piston engine production. Then the next step, according to Göring, was to move underground the most important airframe factories.301At that time, however, BMW moved
ahead with its own plans. In October 1943 Wilhelm Werner, chairman of the Aero Engine Main Committee, recommended the relocation of the entire Allach production to bombproof underground facilities. The RLM offered BMW several caves in West Germany and France. Since relocation to these caves meant a huge investment and posed a range of organizational challenges, BMW and the RLM decided eventually to construct a large fortified production hall at Allach instead. Initially it was decided to construct a long arch-form bunker just south of the Allach complex. Later Speer decided to construct a dome-shaped bunker that was considered more complicated to construct. The Construction Office of the Armaments Ministry reversed the decision in mid–February 1944 and ordered the construction of a simpler cube-like bunker. Following “Big Week” it was decided to construct a smaller two- storied bunker of 32,000 square meters floor space. After more deliberations between OT, BMW, the Jägerstab and the Armaments Ministry it was decided not construct the bunker, but to cover one of the existing production halls with a 60-cm layer of cement. This project was also never completed.302Instead, BMW was incorporated in several underground factory
projects that started to form in spring 1944.
At the end of 1943 Himmler ordered underground spaces to be dug in some former SS quarries in order to use them for different war production purposes. This order set in motion several tunneling projects next to different concentration camps.303Some of these
projects soon came up as potential locations for some of Göring’s production programs. In early December, Himmler suggested to Milch to produce the V-1 in some free underground space in the Mittelwerk complex. Nothing came out of this idea in that stage because Volkswagen, the prime contractor of the V-1 program, started working its own plan to move some of the missile production to an underground facility at Tiercelet.304
The free space at Mittelwerk came up at approximately the same time in another context. In the
search for a suitable place for the Junkers plants, it was found out that the Mittelwerk factory complex could house more production lines. It was therefore decided to relocate some of Junkers’ aero-engine plants involved in the production of the Jumo 004 jet engine and of the Jumo 213 piston engine to a new tunnel complex code named “Anhydrit.” WIFO submitted concrete plans for the new facility in January 1944, and in early February the RLM and the Armaments Ministry ordered Kammler to carry out the project. The SS allo- cated Kammler 10,000 concentration camp inmates for this project.305At the beginning of
February, Junkers also proposed to broaden the scope of its underground relocation and include in the plan airframe production facilities in an unused potash mine near Neusollstedt and in the Heimkehle cavern near Rottleberode.306
In the meantime Göring and the RLM decided to begin the relocation of the aviation industry to underground facilities. The decision was a culmination of a ripening process, which started after the deadly attacks of 1943, and following the preliminary studies done by the Cave Commissioner staff. The formal order was issued on 26 January 1944 and was signed by Milch: “The Reichsmarschall issued a basic order regarding the immediate relo- cation of important Luftwaffe production programs to bombproof spaces.”307This general
order was followed up on 1 February 1944 by a detailed order printed on a unified template sent to most of the important aviation firms. In the blank places each firm was allocated its underground location and the type of aircraft to be produced in them. Focke-Wulf, for example, was ordered to relocate parts of its FW 190 and Ta 154 production to the Prinz Adelbert mine (40,000 square meters) and to a potash mine in Meimershausen.308
A special RLM staff called GL/A Sonderstab H (Höhlenbau— Cave Construction), headed by Regierungsoberbaurat Treiber (an engineer), was appointed to direct the operation. Each firm was ordered to submit initial plans for the relocation to its allocated locations by 15 February 1944. Members of the Cave Commissioner staff helped the firms to prepare their plans. Dr. Solle, a professional geologist from the RLM, conducted on 14 February a survey of caves along the Nekar Valley and suggested the relocation of some Daimler-Benz press workshops into them. The firm integrated his report in its own plans.309Other firms
followed the same procedure, but it seems that this was not done under an atmosphere of extreme urgency. A week before “Big Week” Göring wrote Himmler and asked his help in the relocation of the aviation industry to subterranean locations. Himmler’s positive answer came almost one month later, as the relocation was already in full swing after “Big Week”: “The move of manufacturing plants of the aviation industry to subterranean locations requires further employment of about 100,000 inmates. Plans for their employment on the basis of your letter of 14 February 1944 are already underway.”310
This correspondence proves that Göring clearly foresaw the need to move his key fac- tories underground before the decisive effect of “Big Week,” and that he was looking for unorthodox ways to rush this relocation.
Following “Big Week” and the establishment of the Jägerstab, Göring’s visions regarding the move underground received an enormous boost. On 5 March 1944, Hitler declared that the underground relocation should be viewed not as a stopgap solution, but as a long-term total solution, with the final aim of moving the entire German war industry underground.311
There were some deliberations regarding what scheme of underground relocation should get precedence. Relocation into existing tunnels and caves could be accomplished within shorter times and with much less expenditure. The main disadvantage of these sites was the
restricted size of their tunnels and entrances. Completely new bunkers could be constructed according to specific needs and therefore better suit the requirements of specific production lines. Hitler left the decision to Speer, who favored bunkers, probably because of the archi- tectural challenges involved in their construction.312
After further discussions, which con- tinued until late April, it was decided to construct 6 bunker factories for several highest priority productions and to relocate all the rest to already-existing underground spaces.
The underground relocation required massive and comprehensive administration. Immediately after the establishment of the Jägerstab, each firm allocated a special executive to survey underground facilities in its region in order to determine which of them was suit- able for the construction of underground factory.313The Rüstungskontor, a state-owned firm
which financed different armament projects (Mittelwerk was one of its subsidiaries), admin- istered the purchase of the properties located by the firms. Next it handed over the property to the firm, which carried out the required conversion work. The owners were offered alter- natively to keep ownership of the property by financing its adaptation into an armaments