Hitler’s Mystery Mega-Structures in Central Europe

During the last two years of WWII, the Wehrmacht of Nazi Germany was slowly retreating from the eastern front, pushed back by the mighty blows of the Red Army. The bombing runs carried out by the western Allies from airfields in Britain were systematically hitting most urban centers in mainland Germany and over the territory occupied by the Nazis. It is hard to imagine, but it was in the year 1944, when the destiny of Germany was almost sealed, that industrial production in Hitler’s Third Reich reached an all-time record.

At that time the Germans were desperately short of fuel, raw materials and troops, and their production efforts would not spare them from a complete defeat in 1945. Yet it was in the last stages of the war that some of the most ambitious industrial facilities were designed, built and in some cases made operative before the end of the war.

The driver of the design was in most cases the need to move production lines to secluded and well protected areas, difficult to spot and to destroy through air bombing. As a result, these sites were placed far from urban centers. They were also designed to withstand bombing, by putting them underground, or building them with substantial reinforcement, making large use of one of Nazi Germany’s favorite materials – reinforced concrete.

In this chapter two major sites of this kind are described. One is in southwestern Poland, a region which had been part of the German Empire for long before WWII. The second is in eastern Bayern, today one of Federal Germany’s most prosperous states, close to the border with the Czech Republic. Photographs were taken in late summer 2018.

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Sights

Project ‘Riese’, Poland

Construction around this cluster of underground sites started in late 1943, and reportedly lasted until the closing stages of WWII, just days before the Soviets entered the region. The name ‘Riese’ means ‘giant’ in German, and it is surely well suited for this complex, which while far from finished is really striking in size. It was actually composed of at least six major construction sites, which in the intention of their designers should have been developed deeper in the mountains, until a link could be established between them forming a formidable network of tunnels and large halls.

Besides the size and historical meaning of these sites, what makes project ‘Riese’ so fascinating is also the actual purpose of this incredible complex is far from established. Three major theories exist in this respect. The complex might have been intended to be an underground industrial city, a kind of Noah’s Ark for the ‘superior race’ embodied by the top-ranking military and governmental staff of the Reich, or a gigantic secret laboratory for innovative technologies.

What is sure is that the construction was carried out by forced labor, mainly by prisoners of Gross-Rosen concentration camp, just a few miles north of the complex. For the scope, the Nazis created a number of satellite camps next to the entrance of the  construction sites. Rather incredibly, only very scant traces of the project remain in the written records of key figures of Nazi Germany – Albert Speer’s personal diary notably reports some millions marks allocated for project ‘Riese’, and at some point after the war he cited the item resulting from the completion of the construction works, whatever its purpose, as sized to be capable of hosting some tens of thousands people.

Today, six construction sites have been discovered, of which two – Osowka and Rzeczka, the most conspicuous – have been opened to the public, whereas the other are visitable basically for speleologists only.

Osowka

The first visitable site is in the town of Osowka. This site is composed of two parts, one underground with access from the side of a hill, the other close to the top of the same hill.

The underground part can be visited only with a guide. The plant of the completed construction features two accesses, and you will be driven in using the first and out using the other. Between the entrances, the site is mainly composed of an array of parallel tunnels pointing towards the mountain, connected by long halls.

Close to the entrance you can spot a concrete guardhouse with loopholes for machine guns. Some wooden structures like in a mine have been put in place to give an idea of the appearance of the working technique at the time of construction.

Most tunnels have been dug but not reinforced with concrete walls, whereas others are almost complete, showing a peculiar two-level design. The lower level features a smaller section, and the top one a taller, round shaped section.

A feature of the ‘Riese’ complex is a special technique for building the inner concrete coat of the rocky tunnels, producing the distinctive ‘church-ceiling-like’ appearance of some of the halls, with a round shape and frames close to one another.

The Osowka site features also a collection of smaller artifacts, collected from the ground and dating from the construction years, i.e. from late WWII.

Life-size silhouettes of some WWII tanks are on display, to show how the size of these items was totally compatible with the size of the tunnels, in support of a potential use of the site for weapon manufacture.

The outside part, which can be accessed freely, is the most mysterious. At the base of the trail leading uphill you can spot a strange concrete platform, with provision for – possibly – interred pipelines.

Close to the top of the hill you can find a huge concrete platform, with an apparently chaotic ensemble of slots, pipes, handles, stairs and pools. This item has been deemed close in shape to the base of a service building for the valves and pipelines of a power-plant. Theories have flourished in support of the use of this item as a prototype control system for a nuclear power-plant.

The nuclear program of the Nazis, which indeed existed and is even documented to some extent, is shrouded in mystery for what concerns the actual findings obtained during the war. These dark spots are also due to the destruction of most of the hardware connected with the program everywhere in Germany, and with the inherent secret nature of the program itself. No evidence exists of the Osowka site in the public papers about the nuclear studies of the Reich, so the true purpose of this object is likely to remain an unsolved riddle.

Close by this platform, you can find an original concrete building, part of the same construction plan. It is pretty long, with large windows, and likely intended for troops or technical staff.

Rzeczka

Compared to Osowka, this site is more centered on the inside part. Again, there are two entrances, close by a creek on the side of a hill, providing access to a network of tunnels. Similar to Osowka, close by the entrance you can find guard-houses in concrete. These were built soon, possibly for keeping a watch on the forced workers.

The construction works in Rzeczka were less advanced than those in Osowka. Yet thanks to the lack of the concrete coat, you can appreciate the size of the tunnels, some of which are really tall.

There are small collections of artifacts found in the tunnels, and an original concrete room offers a description of all discovered sites of the ‘Riese’ project.

A 1:1 copy of a V-1 German flying bomb has been placed in one of the tunnels, to show the compatibility of the size of this weapon with the tunnel. Such weapons were reportedly assembled in underground facilities elsewhere in Germany.

Visiting is again possible only with a guide. Some multi-media experiences with sounds, lights and voices are included in the tour, but these are not so impressive for those who don’t understand Polish.

On the outside, you can spot some relics from construction years, including trolleys, and concrete slabs watermarked with symbols of the local construction companies tasked with the practical realization of the site. There is also a copy of a V-2 rocket, operative in the last months of WWII but little effective in changing the fate of Nazi Germany.

Getting there and moving around

As pointed out, the sites connected with project ‘Riese’ are many, but most of them are not visitable unless to specialists and with the help of a speleologist. On the other hand, the two sites of Osowka and Rzeczka are professionally operated as primary tourist attractions. The distance from these two sites is about 20 minutes by car, so you can surely arrange the tour of both sites on the same day, with much spare time in your daily schedule.

At Osowka you can find a large parking and a fully equipped visitor center, where you can book a guided tour, or join a departing one – the only way to get inside. Please note that the number of people admitted on each tour is relatively small, so I would suggest booking at least one day in advance through their website (partly also in English) to be sure to get a place at the time you like. They offer several different tours. The most complete include a visit to a part of the underground site which can only be accessed by boat. This is given only on some days by reservation, and only for groups. The standard tour of the inside is offered several times a day.

The guided may turn out really boring, cause you are provided an audio-guide in English with explanations lasting a couple of minutes for each of the circa ten stops, in face of the Polish-speaking guide talking about 5 minutes per site. You may try to spend your spare time taking good pictures, but even though groups are relatively small, they tend to obstruct the view inside, leaving poor chances for acceptable shots. Furthermore, lighting is not very good, so a tripod would be recommended, except you don’t have the time and chance for undisturbed long poses. Therefore, if you are interested in top-level pictures, you would better arrange a dedicated tour out of the normal touristic offer. Otherwise, you’d better go prepared to a difficult visit.

The outside part of the site is less frequented and more rewarding. It can be reached in about ten minutes following a pretty steep, unpaved trail in the trees. This part is unfenced and unguarded.

The Rzeczka site has only an inside part, which can be visited only on a guided tour. You can join one of the frequent tours they provide even without reservation. There is a small visitor center and plenty of parking space. Similar to Osowka, the guide will speak in Polish, and you are provided an audio-guide in English. The visit lasts less than in the case of Osowka, and the audio-guide explanations are more proportionate to the speech of the Polish-speaking guide, making for a more enjoyable visit. The multi-media experiences are of little relevance for non Polish-speaking people. Outside you can find also some panels with explanations on the history of the site in both Polish and English. Website with some info in English here.

The tunnels in Rzeczka are poorly lighted too, so photographing will be difficult unless with a tripod, but the conditions are not very favorable for operating with a tripod – many people around and short times between stops along the tour.

‘Weingut I’ Aviation Industry Complex, Germany

The giant complex known as ‘Weingut I’, the original codename attributed by the Nazi staff at the time of its design and construction, is the direct result of a plan to relocate all major industrial production lines of the Reich to protected areas, far from the line of the front and from any major urban center. In this particular case, the new factory was intended to shelter the production line of the new Junkers Jumo 004 jet engines for the ‘Schwalbe’ – also known as Messerschmitt Me-262, this was the first jet fighter in the world to be pushed into service, back in 1944.

The huge factory was designed based on a basic module made of a reinforced concrete arch, some 250 ft open, 100 ft tall and 10 to 15 ft thick. This item was to be built on site and partly buried under ground level. Twelve such modules were needed for the complete hangar, with a total intended length of the factory of around 1.200 ft. Of the planned twelve sections, seven were actually built between mid-1944 and the end of the war.

Despite the intended scope was that of hiding the factory to protect it from aerial reconnaissance, due to the size of the construction works the object was reportedly spotted by US aircraft, but not attacked. Actually, the special construction was tested against explosives by the US Army after the war, resulting in the collapse of all modules except one, which is still standing today besides the pretty sizable relics of the others.

The site is not actively guarded, but it is located in a regional nature preserve, so access is through a nice walk in the trees. Once next to the hangar you can find multiple access points.

Close to the main arch, the only one still standing, it is possible to find an explanatory panel in German only. It commemorates also the forced laborers from the nearby concentration camps, who had to take part substantially in the construction works.

Walking under the arch is at your own risk, cause despite the bulky appearance of the structure, smaller pieces of concrete are hanging from from the ceiling. However, a walk inside will give you the most striking impression of the size of the hangar.

Just nearby the remaining module to the west you can find a walkable, half interred bunker, likely with a technical function which is today hard to imagine.

The module still standing today is the westernmost of the hangar, so walking east you will have the chance to step on the roof of the demolished modules. A number of thick iron rods can be spot at ground level.

Walking along the former southern side of the hangar, you can spot a deep well, probably part of the construction strategy. It may have been used to take out the gravel from beneath the base of the arches to lower them to a rest position on more compact ground.

Along the same side you can find a way to walk below the fallen structure. You can also get a view of the edge of one of the modules.

The eastern end of the complex is probably the most hazardous, cause you find an unprotected concrete cliff a good 10 ft high, constituted by the edge of a fallen module.

All in all, the place is a nice example of the undeniable structural design abilities of the German military, really interesting to visit both from a technical viewpoint and as a witness of the utopian visions of the Nazis, which unfortunately cost the lives of many.

Getting there and moving around

Reaching the trail-head is very easy by car. Leaving Mühldorf am Inn for Waldkraiburg along the road St2352, about 0.5 miles south of the crossing with St2550 you will find a sizable gravel factory to your right, preceded by an unpaved road taking west in the trees. You can park on the unpaved road on the northern side of the factory – probably a heir of the original factory built to feed the construction works of the hangar.

From there, you should take the unpaved trail into the trees, closed to vehicle traffic. It is another 0.5 miles to the site, on a flat and easy trail. A quick scan of the Google map will allow you to plan the trip. The place is not remote, cell phones work and you may use a virtual map to get oriented on site. Visiting might take about 2 hours for a very interested subject, including the trip from the parking and back, plus all time needed for pictures .

The Border Forts of Czechoslovakia Against Nazi Germany

The Maginot line – a line of forts running along the French border with Italy, Switzerland, Germany and Belgium – is a widely known example of military engineering from the inter-war period (see this chapter). The adopted construction technique, based on reinforced concrete pillboxes with walls several feet thick, half interred to decrease visibility from above, field cannons and anti-tank defensive guns, witnesses the great consideration given to tanks and aircraft as attack weapons.

Due to the fast movements typical to the new strategy of the German army since the beginning of WWII, the Maginot line is mainly remembered for having not been involved in any major action, and having being largely bypassed. As a matter of fact, the German opted for a bypass also because the line was in place, so it was not as ineffective as it is often thought.

What is possibly even less known is that similar defensive lines were built in earnest in other European countries, before and even during WWII, after the Maginot line had failed to stop the invading German army. The enormous Salpa line, built by Finland against the Soviet Union, was probably the last and most effective to be completed (see this chapter). The Stalin line, prepared by the Soviets against Germany in Belarus, is another example. Another country who invested much in this type of deterrent was Czechoslovakia.

To understand the drivers of the design of the huge line of forts envisaged by the Czechoslovakian government of the mid-1930s, one should take a look at a map of Europe from the time. After the defeat of WWI Germany had managed to keep significant parts of todays Poland. The border between Germany and Poland ran close to Gdansk – aka Danzig in German -, and the province of Lower Silesia with the town of Wroclav – Breslau in German – were undisputed German territory. This means that todays border between the Czech Republic and Poland used to be actually a border between Czechoslovakia and Germany in the years before WWII.

With the turmoil preceding the infamous Munich Agreement and Nazi Germany claiming the right to control ‘Sudetenland’ – a large part of the peripheral territories of todays Czech Republic – in 1937 the Czechoslovakian government quickly started the construction of a huge system of forts to protect the border.

The concept was pretty similar to that of the Maginot line, with extensive underground tunnels to shelter soldiers and ammos, facing to the surface with reinforced concrete bunkers with different purposes, including observation, artillery shelling with field cannons, mutual protection with short range anti-tank cannons, machine guns and grenade-throwing tubes. There were also bunkers for accessing the tunnel system with resupply. About 10’000 light fortifications were actually built, more than 200 heavy fortified positions and a handful of heavy artillery positions.

The geopolitical situation in Europe got worse quickly in 1938, with the annexation of Austria in spring and finally the Munich Agreement, which caused the dissolution of Czechoslovakia. As a result of this internationally approved de facto German invasion, the works on the defense line were halted by the Wehrmacht. A relevant part of the hard construction had been completed, but most of the bunkers were still unarmed or lacked some software – air filters, ammo supplies, everyday items for the troops, etc. – and were not serviceable.

Most of the ironworks, including especially all heavy-metal turrets, were salvaged by the Germans. Some of the cannons found their way to the Atlantic Wall. The most massive concrete bunkers were used to test new weapons. As a result, the majority of the most sizable structures are still today in a partly damaged shape.

Some of the bunkers came to life again in the 1970s, when re-founded Czechoslovakia, that time a satellite country of the USSR living under a repressive and hard communist dictatorship, started a low-paced conversion of some of the structures into nuclear shelters for top ranks of the military and political hierarchies.

Notwithstanding these incidents, todays Czech Republic is duly proud of the significant work which was carried out in the difficult late Thirties. Very much was done for the little time available, and the quality of the design and construction is remarkable. While most of the sites are open only rarely, there are some where you can step inside and enjoy an interesting visit. This chapter covers with photographs and text five larger fortified complexes along this anti-German defensive line, from a two-days visit taken in August 2018.

Map

The following map shows the highlights of each of the five sites listed in this chapter. Please zoom in for greater detail. For the Bouda fort I could not spot and pinpoint on the map all the pillboxes you can easily visit from the outside – this are covered by vegetation.

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Sights

Stachelberg

The Stachelberg site is located about three miles north of the small city of Trutnov. The fort should have consisted of a main entrance and peripheral shooting positions, some of them linked by underground tunnels, to defend the area of the Giant Mountains. Construction works were terminated much before completion, so the surface bunkers forming the ensemble are actually not connected. Yet the major installation, a bulky infantry positions with provision for anti-tank artillery, provides access to an extensive system of half-prepared tunnels, which gives you a clear picture of the size and capacity of the complex.

The site is open to the public, and the ticket office can be found right inside this huge major bunker. From the outside, the volume of this pillbox is particularly stunning. Also interesting are the anti-tank obstacles, which used to be placed along the border line and between the forts, to trap invading columns in a position where anti-tank guns could be most effective.

This multi-level bunker is also place for a little museum on the fortifications, mainly based on explicative panels and scaled models of weapons and of the entire bunker complex. It covers the history of the fortifications, and explains most technical features of their construction. There are no weapons or other software – they were either not installed before the construction works were stopped, or salvaged by the Germans.

The tunnels can be visited on a guided tour only, starting from inside the main bunker with a descent of several tens of feet along a flight of stairs, originally made at the time of construction. The tunnels unfold on the sides of a major, perfectly straight initial track. Some of the lateral halls, intended to store ammos as well as for sleeping the troops, are very large and close to completion, whereas others are just sketched.

The tunnels were dug in the rock with the help of explosives. The next step in the construction works would have been a layer of concrete from the pavement up to the ceiling of the tunnels. This is present today only close to the entry point, at the bottom of the access stairs.

There are at least other five smaller pillboxes which have been preserved to some extent in the Stachelberg complex. They are accessible with different timetables, and do not provide access to the underground – by design, some of them should have.

One of the pillboxes has been colored in a very bright camouflage. I could not find out whether this used to be the standard, but it looks pretty unusual and not really mimetic… There are also refurbished connecting trenches between the smaller bunkers.

The concrete base of a never built bunker can be found not far from the parking area.

Getting there and moving around

Getting close to the complex is really easy, the area is very scenic and a popular destination skiing, and for nature trail hiking in summer. There is a parking on road N.300 from where the museum-fort can be reached with an almost flat, 0.3 miles track.

The complex can be toured on the outside without restrictions. The main bunker has opening times, and the underground part can be toured only with a guide. The guide speaks Czech, but you are provided a leaflet with explanations in English, upon request. The tour takes about 30 minutes, and is offered on a regular basis, with several entries per day. They warn you about the inside temperature, but I found it pretty easy to bear with normal summer clothes. Website here, but you will need some Google translation to find the info you need.

Voda, Brezinka and Lom

These three forts are actually parts of the same system, built on the eastern end of the town of Nachod-Beloves, the major center in a local valley ending in Poland. Three items in the complex are typically accessible to the public.

The one closest to the town, on the bottom of the valley, is the Voda bunker. This is very convenient to reach, and is basically composed of a preserved typical infantry pillbox with provision for machine guns. The bunker has been painted in a credible camouflage. On one end it is possible to note the damage inflicted by the Germans, when they took out the metal observation turret. This kind of treatment – and damage – can be observed on a great many bunkers of the line.

Inside, the bunker has been turned into a local museum on the armed forces. There were border guards operating in the area, involved in skirmishes before and after the end of the war. The weapons originally intended for the fort are not in place, but there is an interesting collection of weapons, uniforms, motorcycles and other gear from the army corps operating around there over the years.

The Brezinka fort is possibly one of the most famous of the entire defensive line. The reason for that is that it was recently restored to look like it should have looked, if only it was completed back in the late Thirties. In the restoration process, weapons and system parts from other locations in todays Czech Republic were brought to the Brezinka site.

The visit of the interiors is really exceptional, even compared to the forts of the other defensive lines in Europe. The fort really looks like it could be put in operation today!

The first part of the visit of this two-levels artillery bunker will take you downstairs, where you can find the sleeping quarters for the troops with a food storage.

Close by, there are two rooms for the electrical generator and for the ventilation system. Here you can see the electrical compressor, with backup manual handles, and the huge air filters. These are multi-stage filters, where each stage was designed to stop different poisonous components in the air. The system is working, so you are given a demonstration of the compressor – interesting to get an impression of the incredible noise this system produced!

On the same floor there is also a telegraph system, which was used to communicate with other bunkers in the complex in case of failure of the telephone link. This system was capable of transmitting Morse signals to the other pillboxes next to it, projecting the signal into the ground and using it as a medium – there were no cables! This allowed it to work even if a direct electrical link was lost.

The upper floor is even more surprising, cause basically all weapons have been restored to their original positions. The Brezinka bunker featured two main firing chambers. The one pointing uphill features two heavy 7.92 mm machine guns Zbrojovka Brno Mark 1937, a very widespread and reliable weapon, with an operational range of 1’000-2’000 ft at 500-300 rounds per minute. These were used to target infantry movements along the border line, pinpointed by anti-tank obstacles. Fire direction was from the observation turret or via an optical aim system. The latter was extremely precise, but more expensive than the machine gun!

In presence of an impenetrable smoke curtain or at night, an open-loop aiming system could be used. This consisted of a board with a precise sketch of the view of the outside from the firing point, mounted on top of the machine gun. A calibrated needle pointer was used to align the machine gun with respect to the target, by simply pointing the needle on the intended target on the board!

The third machine gun is a light ZB vz. 26, a very popular light 7.92 mm machine gun. This was used for close defense of the fort access. There are also grenade throwing tubes for the same purpose.

The other firing chamber points downhill, and is supplied with a machine gun as in the first chamber, plus the assembly of an anti-tank cannon and another machine gun. The cannon is a 4.7 cm Skoda KPUV vz. 38, with an up to 1-mile range at 35 rounds per minute. It could pierce a 50 mm armor from 0.7 miles apart, and was a very effective weapon. This very cannon was already in place before the German invasion, and was taken by the Wehrmacht to the Atlantic Wall in Norway. It has been returned to its original location in recent times.

There are other two metal-reinforced embrasures in the bunker for other two ZB vz. 26s. On the same floor you can find a kitchenette and toilets for the troops, ammo storages, and two observation turrets. The latter feature a working movable floor, to allow tailoring to the height of the observer. The turrets were fitted with a periscope, and were used to direct fire. They weighed 21 tonnes each, and could withstand direct close fire from anti-tank guns!

Finally, the room of the commander and the telephone room – with an original machine from the Thirties – conclude the tour.

The Lom object, five minutes uphill with respect to the Brezinka fort, is another infantry bunker. It has not been refurbished to the level of Brezinka, but nonetheless it is used to showcase construction pieces, weapons and memorabilia from WWII years. The armored turret was taken away by the Germans.

Between the Brezinka and Lom bunkers you can find a section of anti-tank obstacles. The concrete base used to support them can be spotted in several places here and other sites of the defensive line.

Getting there and moving around

These bunkers, and especially Brezinka, are surely among the most interesting of the kind to visit, considering also their counterparts in France, Finland and Belarus.

The Voda site is easily accessible by car. The Brezinka and Lom bunkers cannot be reached by car. You can park on a street close to the trail-head and take the trail. Unfortunately, the road going uphill, albeit not uneven, is extremely steep and about 1 mile long. You should definitely take this into consideration when planning your excursion, even if you are physically well-trained. Very few beverages are available at the Lom site, which is five minutes farther uphill from Brezinka. Nothing is sold at Brezinka.

It is a pity they didn’t prepare a better access road, cause the site is surely worth a visit, and may appeal to the specialist and to the general public – especially children! – as well.

Only cash is accepted in all these sites. The Brezinka site is accessible only with guided tours. Tours were offered every 20 minutes in late August when I visited. You are given a detailed leaflet in English or German, in case you can’t speak Czech. The guided tour of Brezinka takes about 50 minutes.

The Lom site can be toured in 10 minutes, whereas the Voda bunker is worth a 20-30 minutes self-guided visit. Explanations are partly also in English and other languages in the Voda bunker.

Information on these three forts can be found from this website.

Hanicka

The Hanicka site features an extensive underground tunnel system, actually connecting the main entrance to some major peripheral forts. The ensemble includes one of the few most imposing firing units in the entire defensive line.

But what makes this site even more unique is the fact that, after having fallen into oblivion since the end of WWII, in the 1970s it was selected to be developed into a nuclear-proof governmental bunker – codenamed ‘Kahan’. The ensuing modifications altered greatly the appearance of the entrance bunker, and most of the systems you can see today in the underground part are actually dating from the 1980s.

The works on the conversion were carried out at a slow pace, and were actually not completed before the end of communism in Czechoslovakia, the collapse of the Czechoslovakian federation and the birth of the Czech Republic in the early 1990s. The bunker was soon opened to the public as a unique specimen of military building engineering from both WWII and the Cold War.

The tunnels can be be visited only with a guided tour. The original entrance to the tunnel, modified in the 1980s, is the starting point of the visit. The entrance to the bunker looked totally different before it was developed into a nuclear shelter. The modifications at the level of the entrance included the construction of a soft service building, with room for storages of trucks, armored vehicles and other material.