September 2004 Bunker Tour Eastern Germany

Sites Visited


VEB Physics Workshops.

Alt Rehse

Bunker 5005


During our first visit to East Germany in 2001 it was quickly apparent that the country was literally littered with bunkers of every size and type serving a multitude of different agencies. A large number of bunkers were built during WW2 but during the Cold War there was a new sense of urgency with a genuine belief that the country would be attacked by the ‘West’, this led to a new and unstoppable demand for protected accommodation for everyone in ‘command’ at whatever level. There were bunkers for the East German army, bunkers for the Soviet forces that were stationed in the country, bunkers for the East German government and for the Stasi, the East German secret police.  Many of the WW2 bunkers were rebuilt and extended but many new bunker sites were also selected. This bunker mentality carried on unabated until the end of the cold war and just as in Britain, many of the later bunkers that were under construction as the cold war drew to a close were never completed or commissioned.

Today, the majority of bunkers in West Germany are sealed and no longer accessible but in the east it’s a different story; there is less money and high unemployment. Initially many of the bunkers and their associated military complexes were taken over by the German Army (Bundeswehr) but the majority of them were soon declared surplus to requirements and abandoned. Some have found new commercial users, some have been developed as museums but a large majority have just been forgotten and are left open to the elements and the bunker hunters.  One such site is Falkenhagen which although still in the hands of the German Property Services Agency is in reality derelict and gradually returning to nature. With the impending sale of the site our mission this year was to record the bunker and the surrounding surface buildings before the new owners move in. We did visit Falkenhagen in 2001 but, considering the size of the complex, the tour was short with little time to take more than a cursory look at the site. This year we planned to spend two days at Falkenhagen and a further two days looking at new (to us) sites around Berlin.

As usual the visit was co-ordinated by Mike Barton, one of our most active members living in Germany, Mike was able to arrange ‘official’ access to the sites and it was nice to have a key to the front gate at Falkenhagen so we were able to drive right into the centre of the complex hidden deep in woodland.

The Falkenhagen complex lies between Berlin and the Polish border and has a history going back to before WW2. Under German management, it was to comprise of two separate production facilities, only one of which was subsequently used by the Russians. This location was chosen, amongst other reasons, due to its reasonable proximity to the Wehrmacht's experimental site and laboratories in Kummersdorf, close to Wünsdorf and lying some 45 km south of Berlin (small quantities of the incendiary agent - see below - were produced initially in Kummersdorf).

This site was originally designed at the end of 1938 with construction following in mid-1939, under the auspices of the Army's Armaments Office (Heereswaffenamt) as a military factory.  The production facility itself was the bunker complex as we know it and was used for the production of an incendiary agent, chlorine tri-fluoride (ClF3), which the Germans codenamed ‘N-Stoff’.

Somewhat nasty, ‘N-Stoff’ was of interest to the Wehrmacht as it was an extremely effective incendiary agent and when contained in iron vessels, it formed a passivating layer on the inner side of the container and could thus be stored. This also meant, of course, that it could be ‘stored’ in artillery shells and bombs. In contact with materials other than iron, chlorine tri-fluoride causes burns and generates flames, thus making it ‘ideal’ for use against pillboxes or personnel in protective clothing. It is also lethal if inhaled. It was initially planned to use it against filter units, for instance on the Maginot Line, where trials were carried out. The levels of carbon monoxide generated in the trials were far above lethal levels. The excessive heat set free would also have resulted in the individual bunkers being put out of action. Trials were also carried out on the West Wall. Conventional artillery fire and bombs were ineffective. When combined with flame-throwers, chlorine tri-fluoride resulted in temperatures in excess of 2400 °C.

Chlorine tri-fluoride was discovered by Ruff & Krug in 1930. The compound is remarkable for the extraordinary vigour with which it reacts. It destroys glass and quartz except at low temperature; glass wool catches fire in the vapour immediately. Organic substances react at once with inflammation, one drop of the liquid sets fire to paper, cloth or wood. Most elements are attacked explosively and if not they can be ignited by a fragment of charcoal.

Fluorine for the manufacturing process was generated on site by electrolysis of a molten metallic fluoride derived from the common mineral fluorspar brought from Bavaria in Southern Germany.

Trials were also carried out to produce a torpedo driven by chlorine tri-fluoride, which would have left no tell-tale wake in the water.

This part of Falkenhagen continued to be extended until February 1943 at a total cost of 100 million Reich marks and was known as ‘Muna Ost’ (Munitions Plant East). This plant was operated under the control of the Waffen-SS. The original works area was 3176 hectares in size and had road and rail links. Initially the rail links were narrow gauge but eventually a standard gauge connection was made to the main Frankfurt/Oder - Berlin line.

At the centre of the complex was a huge four level bunker that was used as the production and storage facility for N-Stoff; the fourth floor being some 15 metres below ground level. The total bunkered area of the four floors is some 15,600 square metres. The bunker is about 27 metres high and has three large towers located above the bunkered area to serve as air intakes or exhausts for personnel and plant. The towers served other purposes when the bunker was being planned originally, i.e. gas washing for chlorine, emergency air, etc. The Russians were therefore obliged to modify the inside of the towers to suit their purposes (filter systems).

The four floors differ in plan: Level 1 has a 189 metre long railway tunnel running along, but forming part of its south side, Levels 3 and 4 extend to the west of the higher levels (80 x 30m) and served originally for storage and emergency flooding purposes. The main core running downwards through the bunker is some 40 x 55m.

A separate 90 metre tunnel leads out from the west side of the bunker at Levels 3 and 4 to a water tower to the west of the three towers located over the bunker itself which would have provided a further source of emergency water supply. This tunnel was blocked off by the Russians, who built an additional technicians' access and emergency exit into the side of the 90m tunnel. This was tiled, acid-resistant and served as an air exhaust from the production facilities: it could have been flushed with water. Level 3 housed, amongst other things, the four chambers, where some 900 cubic metres of water were stored.

There was rail access through Level 1 of the bunker with the two tunnel entrances disguised by camouflaged corrugated iron sheds. 64 storage cells were located on Level 4 (4 lines of 16), each of these would have housed an iron container weighing 2.5 tonnes and containing 1 ton of chlorine tri-fluoride.  An overhead monorail system was used for moving the containers around Level 4 and they were raised up to the upper rail level by lift.  In view of the highly incendiary nature of this product, extensive measures were taken to ensure that the production and storage facilities could be flooded in the event of an accident. There is a small aperture in one corner of the ceiling in each cell to provide entry for the water and escape for fumes.  On Level 3, above the chambers there are four lines of pressure relief valves from where the water would be released into the cells below.

Fortunately, production never really got underway until the autumn of 1944 with the result that only some 30 - 50 tonnes of chlorine tri-fluoride were produced by the time the Russians arrived, although the planned production figures were for 50 tonnes a month, rising to 90 tonnes. The actual production costs were some 100 Reich marks/kg.

A second facility was developed from mid-1943 in the eastern part of the site as the Sarin II Complex, a chemical agent plant that was built on the suggestion of Reichsminister Speer. This eastern part of Falkenhagen was operated by I.G. Farben, the largest chemical manufacturing enterprise in the world, which led to a conflict of interests with the Waffen-SS. As a result, the Waffen-SS retained control over Sarin production.

 The Sarin 2 production plant was only 70 – 80% completed (some of the unfinished buildings are still standing as they were outside of the Russian restricted area and, therefore, not required): consequently, Sarin was never produced in Falkenhagen. The nerve gas Sarin was developed by I.G. Farben at Elberfeld in 1937/38. Its name came from the four scientists involved – Schrader, Ambros, Ritter and Linde - and was designed to make up for the production deficiencies of the nerve gas Tabun, Sarin being some six times more effective than Tabun (both Tabun & Sarin were originally developed as pesticides). The Sarin production technology was subsequently improved at the plant in Spandau, Berlin

As the Russians approached the German borders, a Führer Command was issued in February 1945, stating that no combat agents or munitions filled with such agents were to fall into the hands of the Russians and relevant documents were to be destroyed. Numerous special trains transported the ‘products’ from Falkenhagen and Kummersdorf to Stulln in Bavaria.

From the end of February – mid April 1945, Falkenhagen was used briefly as a regimental command post (CP) with a medical post being established in the tiled area of the bunker, used later by the Russians as a decontamination area. From 14 - 18 April 1945, elements of the SS Division Gross Deutschland prepared to defend the site, but left before the Russians arrived. The Red Army occupied the site in April 1945 and it served briefly as a sanatorium for the local Russian military forces. They also made use of the former storage facilities at Level 4 in the bunker (the ‘cells’ later used by liaison officers from the Warsaw Pact as offices) for employing German PoW's to fill artillery shells; several explosions occurred. In accordance with the Potsdam Agreement, the Russians dismantled the bulk of the former production equipment in the bunker and transported it, together with the works railway system, to Russia as reparations, without apparently knowing the true purpose of the facility at this time. Most of the WW2 buildings were either destroyed by the Russians or allowed to fall into decay. Some were taken over to suit their own purposes.

The tiled area on the top floor of the bunker (later used by the Russians as the airlock system) was used for a short time as a field hospital by the Red Army.

No precise details are available on what was removed from the bunker complex by the Russians. One eye-witness stated that they removed several large compressors from the lower levels of the bunker. Evidently, some of the explosive material was still stored on the bottom level (64 storage rooms) and some explosions (and injuries) occurred as the material was being transferred for removal.

Dismantling of the production facilities and rail track took place between 1948 and 1954 and during that period it was used as a vehicle maintenance workshop. The heating plant, drinking water system and the sewage plant were evidently still functioning. From 1955 - 1959 it apparently served as a quarantine station for the Frankfurt (Oder) and Fürstenwalde area and it was not until the early 60s that they started a substantial rebuild and conversion there, lasting into the 70s, to establish the normal buildings which military units require. During this period they deliberately avoided using parts of the Sarin production area, having discovered in the intervening years what the Germans had intended to build there, other areas were either demolished or converted to more practical purposes: coal storage, etc.

The outside buildings were converted to normal military usage: accommodation, offices, medical centre, fire station, etc. The Russians were able to continue using the wells for their water supply.

At first, the locals were tolerated as they made their way through the complex to nearby villages or to collect firewood; even visits to the unit cinema were allowed.

However, from 1961, Germans were no longer allowed access to the property (at other Soviet military locations in East Germany, local workforces were employed). This also restricted the amount of eye-witness reporting compared with other locations. A nearby GDR research centre endeavoured to establish contact with the Russians (common at the time), but were told to enquire in Wünsdorf. The site was described as being a technical service point, but the main construction work at this time was undoubtedly directed at converting the production bunker into a major command post for the Warsaw Pact, eastern Europe's equivalent of NATO.

 The complex was so secret that even the chief signals officer of the East German army, General Paduch, had to arrive at a rendezvous at night and was then taken by car on a one-hour drive until they arrived at the bunker, where he was only allowed to see the communications centre for the purpose of the visit before being escorted out for the return journey.

Nothing has been officially published or revealed by Russian/Soviet sources on the role of Falkenhagen, but the command post was probably a forward CP, serving the general staff of the Soviet Union's armed forces on the Western Theatre. It should be noted that the Warsaw Pact would have ceased to exist as a military level in the event of war breaking out, i.e. control was in Russia’s hands.

There was a slight lull in building after the initial wave, but further construction work took place throughout the 80’s when the Soviets modified parts of the bunker complex and added numerous buildings to the garrison, particularly in the 70s and early 80s.  Level one housed a UESO (Russian abbreviation for the special bunker servicing unit) with a dormitory in the corridor and in an area above the ceiling. On this level there was also an air detector room, 4 transformer rooms close to the south entrance, water storage tanks, sewage disposal, diesel tanks, compressors and compressed air plant.  On Level 2 there were numerous offices, a safe, battle management centre, senior officers' bathrooms and toilets, ventilation, computer centre and offices for deputies. Level 3 housed a communications centre and the standby generators were located on Level 4, where the 64 WW2 chemical storage rooms were converted into offices.

From 1990 - 1992 the machine went into reverse and the facilities and equipment were gradually run down and shipped out to Russia. Falkenhagen Garrison (Military Community No. 1) was handed over by a representative of the West Group (the Soviet/Russian forces in East Germany) to the German authorities at the end of September 1992 and is currently in the hands of the German PSA and is awaiting disposal.

Interestingly, the last commandant of the site ‘revealed’ to the press at the handover that the complex had served as a design and test centre for communications equipment (telephones and radios). For this, they had used the four bunker levels. The workshops had only been used for repair purposes. It was rumoured at the time that the Russian press (Pravda) also revealed that Russian pigs had recently been taking flying lessons

Most of the surface buildings at Falkenhagen are open, windowless and easily accessible. Most of the buildings are Russian with their characteristic brick work with one brick laid directly on top of the next; it is surprising some of the large barrack blocks haven’t fallen down. Inside the blocks there are elaborate murals in many of the rooms. A standard gauge railway line still runs along the cobbled road running through the centre of the site on one site there is a huge rail transfer shed and on the other an equally large workshop with a gymnasium alongside. The workshop with its large overhead crane still intact has a an upper gallery at one end overlooking the shop floor and at the other end steps lead up to a wood-panelled sauna with a plunge pool in an adjacent room. The gymnasium has a full sized basketball court, again with impressive murals on the lower level, with further exercise rooms with wall bars on the upper floor.

There are several heating plants within the complex with much of their kit including boilers and water tanks still in place and overlooking the site is an electricity sub station complete with transformers and  a fully kitted out control room.

A low hill rises above the complex covering the bunker itself. There are four access points into the bunker: the main access being from either end of the railway tunnel that runs right through the hill. There is a third (main technicians') access from a surface building and a secondary technicians' access and emergency exit via a tunnel and spiral staircase located on top of the hill alongside one of the ventilation shafts.

The bunker has been largely stripped of all original fixtures and fittings although the main blast doors are still intact as are the large number of smaller gas doors passing through the tiled decontamination areas at both ends of Level 1.  Perhaps the most impressive feature still remaining are the three huge diesel tanks spanning three floors and the 64 pressure relief valves in four lines of 16 on Level 3. These would have allowed water to flood the storage cells on Level 4 in the event of an accident.

After two days at Falkenhagen it was time to move on but we didn’t have to travel far. There is a second military complex close to Falkenhagen which was the site was an outstation of the ‘VEB Physics Workshops’ in Berlin-Rahnsdorf (south-east area of Berlin). This was set up in 1959 after it had become clear to the East German authorities that scientists in the USA, the USSR and the UK had commenced top-secret research in the early 50’s into problems of a controlled thermonuclear reaction. It was apparent that a high-temperature plasma of some 100 million °K would be needed to create the fusion of the light cores (hydrogen isotopes of deuterium or tritium) and the heavy cores (helium isotopes).

In order to keep abreast of theoretical and technological developments elsewhere, it was decided in 1957/58 to establish the institute in Rahnsdorf to look into the associated problems. The institute (Institut für Halbleiterphysik [IHP]- Institute for Semiconductor Physics) was assigned to the East German Ministry of Defence for security reasons and described as being the ‘VEB Physics Workshops’ (VEB = state-owned facility). However, it soon became apparent that more space was needed for experiments in the field of high-temperature plasma physics, located ideally underground and in a lightly inhabited area. Such a site was offered by the former armaments facility of the Third Reich on the east bank of the Schwarzer See (Black Lake) just to the east of Falkenhagen. Due to its ferro-concrete construction, this facility provided a natural Faraday cage, i.e. it provided an electrical screen, thus enabling the plasma experiments to be carried out without any electrical interference from outside.

The facility provided a production hall some 400 m² in size and 8 m high. The other levels were 3.7 m high, intermediate floors some 1.8 m high. These levels were divided into rooms or served to provide the normal services (water, electricity, HVAC).

The bunker here is located at the rear of the administration complex and is set into a hillside overlooking a lake.  We entered through the emergency exit close to lake level and climbed up to the vast production hall in the centre of the bunker.  Although largely stripped of all original fittings there are a number of electrical cabinets still in place and the room is lit by two windows high up on one wall opening onto the hillside. The bunker itself is on at least five levels (with other sub levels) with a lift still in place linking each level.

On day 3 our destination was Alt Rehse. The 65 hectare medical training centre at Alt Rehse was opened in June 1935, an event that was broadcast live on the radio. In contrast to numerous other Nazi concrete monstrosities, the plans for the complex in Alt Rehse (Mecklenburg) envisaged a series of buildings resembling farm houses in the local style. This may well have upset the artistic streak in Hitler as he was somewhat annoyed when told of the plans at a late stage in their development. As a result, he never visited the centre.

The school was intended to become the medical centre within the Third Reich where doctors, midwives, chemists and health officials would be taught the party line with regard to racial politics, eugenics , ‘racial hygiene’ and euthanasia, which would in turn lead to the legally prescribed sterilisation and death of those unfortunates who fell within the clutches of the race laws and to the thousands of ‘patients’ who were experimented on and killed in the numerous sanatoria scattered throughout the Third Reich.

Doctors considered how many patients could be annihilated in an hour, or planned how to gas the physically disabled or discussed the trials to be carried out in the concentration camps. One of the doctors, Alois Boehm, actually gave up his own disabled son to be subsequently killed.

The site was guarded by members of the SS, and signs of the previous occupiers can still be found: swastikas carved into the gatehouse and the construction date ‘4 years’, i.e. the fourth year after the seizure of power by the Nazis, in a beam of one of the farmhouses. The motto of the medical centre - My honour is loyalty - is concealed by a porch dating from GDR times.

Alt Rehse served various purposes in the years after WW2, at the very end even as a rest home for East German military officers.

From 1978 - 1982 construction took place within the original site to build the northern equivalent of the multi-bunker complex at Söllichau, NE of Leipzig, which Sub Brit visited in 2001.

From the German point of view, the German Democratic Republic (GDR) was divided into two military commands: Military District V in the northern half of the country and Military District III in the south. MD III served the 3rd Army and was based on Leipzig. In the event of mobilisation, a further army would have been formed, the 13th , headquartered on Söllichau.

In the north, the situation was similar: the 5th Army, based on Neubrandenburg, with the mobilisation army being the 15th, headquartered at Alt Rehse.

For this purpose a large prefabricated bunker was constructed to the south of the medical training centre. This consisted of four small staff bunkers and the main command bunker built of prefabricated ‘U’ shaped concrete arches that were earthed over. The bunker is roughly ‘H’ shaped with the main communications centre in the crossbar of the ‘H’. This crossbar is also extended north and south making a total of six large chambers radiating from the command centre. Each of these chambers would have accommodated three signals trucks with satellite dishes on their roofs: these would have been permanently ‘plugged in’ to the main communications facilities until required for action in the field.

Each of these chambers has two heavy steel blast doors and at the back of the chamber smaller gas doors into the communications centre which consists of a single spine corridor along one side giving access to a number of rooms. One of these rooms still contains the main distribution frame and other electrical switchgear, another contains gas filters and a large fan. Toilets, showers and three ventilation plant rooms are located on an upper level where there is also an emergency exit.

The bunker is located in an inner compound within the Alt Rehse complex.  Just outside this compound is one of the houses built during WW2. The basement of the house is ‘bunkered’ with blast doors into each of the rooms some of which still contain electrical switch gear.  One of these doors gives access to a tunnel which runs under the fence into the inner compound. Half way along this tunnel there is a small personnel shelter on one side with its own ventilation plant.  Other personnel shelters can be found scattered around the grounds.

The complex at Alt Rehse has been empty for some years but the site is secure with an internal low voltage electric fence and the site is well maintained.  It is currently used as an occasional meeting place-cum-exhibition which documents this aspect of Germany's and the medical profession's history. It is hoped to develop this as a tourist attraction although the bunker will probably not be included as part of the tour.

Our final destination on Day 4 was to ‘Bunker 5005’ at Biesenthal. The 5000 series of bunkers were built by the East German Government in the latter years of the cold war and employed all the latest technological advances. Last year we visited 5001 at Prenden which is a three-level suspended bunker for Erich Honecker, the East German leader. 5005 was built as a central command centre for the Stasi, the East German secret police

The bunker is located on the road linking Biesenthal and Sophienstädt, some 33 km to the NE of Berlin. The NW limits of the restricted area lies alongside the  A11 autobahn (Berlin - Stettin).

The bunker is located inside a secure 20 hectares inner compound inside the main 293 hectares administration and domestic complex.  The bunker has two storeys and cost, together with auxiliary facilities, some 100 million marks. It was not the largest bunker in the East German collection, but was technically the most advanced one.

It was designed to accommodate 160 personnel and could withstand a shock wave of 5 kp/cm². Further, it was resistant to a vertical acceleration of 4g, a horizontal acceleration of 2g, and was NBC-resistant.

Problems during construction (holes in the walls between rooms for cables and pipes were forgotten) meant that these had to be subsequently made manually. It was completed at the end of 1988 after the various construction problems had delayed intermediate acceptance dates. Due to historical events leading to the end of the Cold War, the bunker was never officially brought into service.

The security fence and the four-storey ‘accommodation building’ can be seen from the road, along with various other buildings in the complex. The inner compound (‘Parkzone’ in German) with the actual bunker is 6 hectares in size and is located on the east side and has its own high-voltage security fence. Due to its oversensitivity and the fact that it was not divided into separate isolated sections, the high voltage fence was frequently out of action.

A normal military assault course was what the casual observer would have seen on the raised ground within this secured area, plus a large 4-storey building together with two smaller buildings. Parts of the assault course conceal the emergency exit from the bunker. The ‘accommodation block’ was the surface HQ building. Its cellar, under a very thick ceiling, formed an area which could be rapidly turned into further protected working areas and is the access point to the tunnel leading to the bunker proper. The tunnel passes under the equipment building on the surface, which provided an access point for lowering equipment into the bunker complex, which lies under the raised ground.

The bunker is of monolithic construction with the most important areas being located at its centre: the outer ring of offices and rooms could therefore have served as a crunch zone to protect the inner area. The entrance area housed the normal decontamination facilities and rubbish chutes for contaminated outer clothing, with the whole section here being under the visual control of the airlock commandant. A second decontamination section provided further showers and additional chutes for other clothing. Personnel entering the complex in times of crisis would have been issued with completely new sets of clothing.

The upper level of the bunker was set aside for staff and accommodation areas. These were located around a ring corridor. The inner core at this level included the situation room with a map wall, armchairs and a control desk. The room is on two levels;  the maps would have been marked up in a neighbouring room and then moved in on rails. Erich Mielke, the last head of the Stasi, had his working and living quarters adjacent to the situation room. These are reasonably basic and functional. Evidently, however, his subordinates had wanted to impress him and had initially aimed to provide a far more impressive arrangement. Following internal complaints along the lines of increased costs without an increase in efficiency (an estimated additional 3 million marks to bring it up to international hotel standards), reports and counter-reports were written. It was claimed that the additional fineries (wood panelling, carpets, wooden floors, fashionable furnishings) were a fire hazard and that "we had cut back costs for the construction of missile facilities, but were throwing money out of the window for the interiors of bunker complexes". Russian experts were also quoted who had criticised the level of such fineries, which added nothing to the functionality of the bunker. Other rooms demonstrate the normal spartan approach.

The lower level houses the services section and dispatcher (control) room in the centre. The standby generators were located directly under the main entrance in the upper level; here three marine diesels, each 400 kVA, would have powered the complex. This level also contains wells, water conditioning plant and food store, computers, communications and the main distribution frame.

All the blast doors, decontaminations areas, ventilation plant, filtration plant and water purification plant are still in place and are in good condition. The three marine diesels have been removed and the computer and frame rooms are in poor condition. The main distribution frames are still in place although most of the wiring has been stripped out. In the communications rooms racks of equipment litter the floor and the main (plant) control room for the bunker has been ransacked and although largely intact is a mess with some fire damage to one of the dispatcher’s consoles.

The upper domestic rooms are largely empty although there is some furniture in the situation room and Erich Mielke’s personal toilet is still intact with its brown glazed tiles! Both levels have several dormitories with bunk beds suspended from the ceiling.

Most of the surface buildings are still standing within the main compound and within the inner secure compound but the site is in the process of being completely cleared.


Mike Barton

Paul Sowan

Paul Bergner

Heini Hoffmann

History of 5005 translated from ‘Befehl Filigran’ by kind permission of the author Paul Bergner

The translated history of Falkenhagen was taken, with permission, from ‘Objekt Seewerk’ by Dr. H. Hofmann (ISBN 3-930588-66-8). This book is in German. Dr. Hoffmann headed the IHP facility at Falkenhagen and acted as out guide in 2001.  

Those present from Sub Brit were Mike Barton, Nick Catford, Dan McKenzie, Robin Ware, Mark Bennett & Jane MacGregor