Berlin - The water is ankle-deep. Brown sludge reflects the light from our flashlights. We trudge along in rubber boots. The ground is uneven and full of holes. One false step could have far worse consequences than getting wet.

The water undulates in the darkness, sparsely lit by our flashlights. The air is stuffy, the smell is musty. It isn’t cold, but we can see our own breath.

In this strange place, one question in particular echoes over and over: what if Germany had won the Second World War?

If it had, cars would be passing day and night through this tunnel, which is nearly 15 metres wide and more than 4.5 metres high. On the street, seven or eight metres above us, Wehrmacht soldiers would parade on memorial days.

Cover: Berliner Verlag, photo: Horst von Harbou/Deutsche Kinemathek
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Sascha Keil lights our way through the darkness.

“We’re standing in the last walkable underground structure built during the redevelopment work for the capital of the German Reich,” says the historian. “We're directly below Straße des 17. Juni, near the Soviet War Memorial.” Keil is a member of the board of Berliner Unterwelten e.V., an association which occasionally offers special tours of this tunnel. Two additional unused tunnels are nearby, just a few metres to the east: one for cars, the other for a metro.

These redevelopment plans, spearheaded by Hitler’s chief architect, Albert Speer, are featured in history books as part of Welthauptstadt Germania (Germania, world capital). To learn more, we leave the tunnels below Tiergarten and head off to the district of Wedding.

A permanent exhibition titled “Hitler’s plans for Berlin: The Germania Myth - Vision and Crimes” can be found in the Gesundbrunnen U-Bahn station. It is curated by the historian Gernot Schaulinski and maintained by Berliner Unterwelten.

The exhibition space is high and long. Right in the middle of the exhibition featuring multimedia stations, fragments of columns from the Reich chancellery and objects found on the grounds of the Klinkerwerk concentration camp near Oranienburg is a large model. It presents Berlin as envisioned by Hitler and Speer: a city for a society forced into line, that should “understand National Socialism as the core and goal of its existence”, in the words of historians Gernot Schaulinski and Dagmar Thorau.

Photo:  Andreas Klug/camcop media
Historian Alexander Kropp is one of the curators of the permanent Mythos Germania exhibition in Gesundbrunnen metro station.

Alexander Kropp looks down at the model. He is one of the exhibition’s creators. “A large number of myths are associated with Albert Speer’s plans for the world capital,” says the historian. “The goal of this exhibition is to deconstruct these myths and provide information in the classic sense.”

The term “Welthauptstadt Germania” itself is a myth, one coined after the war. “There are two Hitler quotes,” explains Kropp. “In one, he mentions a world capital, in the other, he mentions Germania. These two comments were put together in the blurb for Speer’s memoirs. They are not mentioned anywhere else.”

Speer himself is another myth. “Speer always presented himself as an apolitical technocrat,” says Kropp. “But he was much more deeply enmeshed in the National Socialist plans for extermination, the persecution of the Jews and the ‘Final Solution’ than he wanted to believe.” His involvement did not start when he was named Reich Minister for Weapons and Ammunition in 1942, but instead as general construction inspector for the imperial capital, a post with the responsibilities of a minister which began with the redevelopment of Berlin in 1937 and was intended to end in 1950.

All work on the new capital stopped after the defeat of the Wehrmacht’s 6th Army at Stalingrad in February 1943. This also included the construction of the military-technical college southwest of the Olympic Stadium. The college was planned as the first section of a university city.

More than a shell construction was never built. Following demolition after the war, the remnants of the building were buried under rubble and trees were planted on top. This is how Teufelsberg, or Devil’s Mountain, was created. During the Cold War, its summit was used by American and British intelligence and security forces.

Photo:  ullstein bild
The “Victory Boulevard of the Third Reich”, 7,000 metres long and 120 metres wide, was intended to connect the Great Hall with the Triumphal Arch and Südbahnhof.

The Germania model that Kropp stands before is a movie prop; it was filmed in Der Untergang (Downfall) and Speer and Er (Speer and Him) but “essentially presents what was planned,” the historian assures. “This middle section of the north-south axis, about seven kilometres long, has been shortened and is thus presented less accurately in parts. This is precisely the part that always interested Hitler. It has two major features: the Great Hall in the bend of the Spree river and the Triumphal Arch to the south.”

Two main thoroughfares were intended to mark Berlin as a stage for parades: the north-south axis as the “victory boulevard of the Third Reich”, a 120-metre-wide boulevard intended to connect a northern train station in Moabit with a southern train station in Tempelhof, and the east-west axis that was intended to run from Wustermark to Frankfurter Allee via Heerstraße, Großer Stern, Brandenburger Tor, Unter den Linden and Frankfurter Tor.

Speer was able to complete a seven-kilometre-long section of the east-west axis in 1939. It featured the Siegessäule (Victory Column) that he moved from Königsplatz in front of the Reichstag to Großen Stern and elevated by 7.5 metres. It also had street lighting made from two-armed candelabras whose outer shell he designed. There are still 800 of these lamps standing between Theodor-Heuss-Platz and S-Bahnhof Tiergarten.

Speer also constructed three tunnel supports below the Tiergarten at the intersection of the north-south and east-west axes: two for street traffic and the third for a planned metro line G between Lübars and Marienfelde.

We return to the tunnel below Tiergarten. Sascha Keil shines a light into the past: there are fixtures for a fan on the walls of the air shaft we climb down into; on the ground, uneven and full of puddles, are the brick remains of a socket that once bore a staircase; plastic sacks and bags of unknown origin with equally unknown contents rot away in the tunnel.

On the dry floor at the southern end of the tunnel, the light of Keil’s flashlight is reflected by the ends of steel beams that are anchored deep within the earth to provide stability to the structure. Frames made of metal bars for the cable bundles hang at the transition points from the longitudinal walls to the ceiling. Niches for lights extend through the ceiling and a part of the walls.

Photo: Eric Richard
The historian Sascha Keil from Berliner Unterwelten e.V. stands in one of three tunnel supports below Straße des 17. Juni and the Soviet War Memorial.

A brick wall with two culverts divides the structure in the tunnel base, which is filled with water; behind it, the tunnel rises again and the floor is dry. “The water down here is rainwater, it comes through the air shaft,” says Sascha Keil. “The structure doesn’t leak. That continues to astonish architects and engineers.”

The 87-metre-long tunnel, which curves to the east, has been lying empty below Tiergarten since 1938. Its twin lies next to it, about the same length, four metres deeper and curving to the west. The course of the war resulted in both tunnels remaining unfinished, just like the 220-metre-long, 16-metre-deep metro tunnel located further to the east.

The tunnel envisioned for street traffic was used as a factory towards the end of the war: “Small parts for the defence industry were produced here,” says Sascha Keil. He shines his light on the floor, pointing out the remains of machine bases, at the ceiling, where a lamp still hangs, and at the wall, where there’s a niche for a fire extinguisher.

Keil thinks it is probable that this structure, with its cement ceiling and soil covering, also served as an air-raid shelter at the time: “You can imagine that not only workers, but also their close family members, took shelter here. Most of the public shelters were overfilled by the end of the war.”

The light of the flashlights plays with our shadows. Or is it the other way around?

Dead silence.

What if?

Hitler would have cemented his claims to world dominance with the new imperial capital. The Great Hall stands as a symbol for his megalomania. The colossus was intended to tower over the bend in the Spree river, in the area between today’s Hauptbahnhof and the Bundestag's administrative buildings. Covering an area of 300 by 300 metres and reaching a height of 320 metres (four times as high as the Reichstag), the Great Hall would have been the largest building in the world, a space for 180,000 “national comrades” to pay homage to their Führer. Out front, “Adolf-Hitler-Platz” was intended to be a place of assembly for one million subjects.

Photo: imago stock & people
The Schwerbelastungskörper, or “Nazi-Klops” (Nazi meatball) as it is more commonly known, is located at General-Pape-Straße 34A in Tempelhof.

The Schwerbelastungskörper, a heavy load-bearing concrete cylinder, attests to how meticulously the urban planners worked. We leave the tunnel once again and turn our attention to Tempelhof. At the corner of General-Pape-Straße and Loewenhardtdamm stands what Berliners ridicule as the “Nazi-Klops”, or Nazi meatball: a cylinder driven 18.2 metres into the ground with a diameter of nearly 11 metres with a second cylinder on top of it, 14 metres high and 21 metres in diameter. This construction of reinforced concrete that weighs 12,650 tonnes (about the weight of 22 Airbus A380 wide-bodied aircraft) was to test the load-bearing capacity of Berlin’s subsoil.

Michael Richter leads us into the cylinder, not only into the upper-level measuring chamber, but also into the one below, which is not open to the public. “What we have here is engineered uncertainty,” says the architect, who is also a member of the Berliner Unterwelten association. “At the time, the engineers weren’t sure they could build something so heavy.”

Something as heavy as the Triumphal Arch on the north-south axis: 117 metres high, 170 metres wide. The names of all the German soldiers who fell in the First World War were intended to be chiselled into its stone.

“The Triumphal Arch was meant to be the Dolchstoßlegende [the stab-in-the-back-myth, a widely spread rightwing conspiracy theory that Germany did not simply lose the First World War, but was instead betrayed] in a built, physical form,” said historian Alexander Kropp at the Mythos Germania exhibition. “Hitler wanted to reinterpret Germany’s defeat as a victory.”

We climb into the underbelly of the cylinder, over an iron ladder dotted with drops of condensation. Nine metres down, we stand in a small room from which four tunnel stubs extend like a cross and which end after three metres. There is a musty cellar smell. Stubs of conduits rise from the ground, for an altimeter, for example, as well as cables for barometers and thermometers. All of this equipment has been removed. Rubbish lies here and there: the remains of a ladder, lids of pots, the shards of a beer bottle; construction rubble overflows from an air vent.

Photo: Thomas Uhlemann
Architect Michael Richter, a member of Berliner Unterwelten e.V., climbs into the underbelly of the Schwerbelastungskörper. Construction engineers wanted to use it to learn how much weight the Berlin soil could support.

“We found it like this,” says Michael Richter, “and we left it like this.” He looks at the ground. “There are still nine metres of concrete below us.” There are about 20 metres of concrete above us. The cylinder, stuck into the earth like an enormous screw with an equally enormous head, exerts a load 12.65 kilograms per square centimetre on the ground.

The Inspectorate General working under architect Speer built the Schwerbelastungskörper from April to November 1941 with the help of French forced labourers. The surrounding area was meant to be raised so high afterwards that it would cover the heavy load-bearing body. Following this logic, it would have been possible to look straight from the Triumphal Arch (placed where Dudenstraße is today) to the Great Hall.

Nothing would have exerted more force on Berlin’s soil - made up of sand, gravel and clay - than the Triumphal Arch: it would have exerted a force of 116 tonnes per square metre; by comparison, the Great Hall would have exerted 92 tonnes.

The Schwerbelastungskörper sank further into the ground even during its construction, as the Deutsche Gesellschaft für Bodenmechanik (the German Society for Soil Mechanics) found: by July 1944, it sank by 18.6cm and tilted 3.5cm. When a subsequent measurement was made after the war in 1948, it had only sunk an additional 0.7cm. This makes architect Michael Richter think: “Even today, it has scarcely sunk any further.”

In principle, the Triumphal Arch would probably have had to have been built on concrete pillars driven deep into the clay. There would have had to have been enough money, construction materials and labour for the redevelopment of the “capital of the world”. Years before the war he unleashed, Hitler had a new Berlin in mind, one intended to be built on the backs of subjugated peoples, enslaved labourers and doomed prisoners. The new capital would have been built on a foundation of crimes against humanity.

This included the forced eviction of 250,000 apartments and the persecution of Berlin’s Jewish population. With the help of lists that Speer had drawn up to seize the property of Jewish citizens, 55,000 Jews in Berlin were deported to extermination camps.

Laser scan:  Michael Assig/Archiv Berliner Unterwelten e.V.
This laser scan shows that the tunnels run under the Tiergarten right by the Soviet Memorial. Building the memorial there after the war was a conscious decision by Joseph Stalin.

We return to below Tiergarten. We enter the northeast part of the tunnel, which curves to the east. We stumble over a concrete tile, a seal that would have covered the hole left in the ceiling from a pillar.

Rust brown streaks adorn the walls at waist height. They indicate the water level in 1967, when the tunnel was rediscovered during the reforestation of Tiergarten. The shafts were plugged with rubble and scrap so that the water which came from there could not evaporate.

A second shaft yawns at the end of the tunnel. It is sealed with a slab of concrete. A stone stairway stands within it, very steep, very worn. “Now we are standing directly below the Soviet War Memorial,” says Sascha Keil. It is no coincidence that it was built on the former victory boulevard. “This is exactly where Stalin wanted to leave his footprint, as a sign of his victory.”

We turn around, slogging through the water again. A thought arises: it’s monstrous that brown sludge is sloshing around in hollow skulls once more today.