The Boros Collection occupies an Albert Speer-designed bunker in Mitte.
When Berlin became capital of the united Germany in the nineties, the city had to confront many ghosts of its architectural past: the Berlin Wall - now running through prime real estate - and Nazi-era municipal buildings, some of which became home to government ministries.
But nobody wanted to acknowledge the history embedded in the city's sandy soil. Unlike other European capitals, which have turned their underground infrastructure into tourist attractions (think of the Paris catacombs), Berlin wasn't quick to celebrate its network of Nazi air raid bunkers and nuclear fallout shelters. But now those military monoliths are finding new life as historical attractions, and in one case as an edgy contemporary art gallery.
After the fall of the Wall, "the city had found no way to deal with this history," says Dietmar Arnold, a city planner who has written a history of Berlin's underground. To change this, he founded Berlin Underworlds, a non-profit association that preserves the city's bunkers, subway stations and tunnels and makes them accessible to the public. In the first year of operation, the Underworlds had 2,000 visitors; last year, 150,000 people took one of their tours.
Berlin Underworlds offers thematic tours of Second World War bunkers and atomic shelters, along with subway stations and sewers - many of these systems are interconnected. The main entrance to the Underworlds is at the north Berlin subway station of Gesundbrunnen, right under a Flakturm ("flak tower") built in 1940 to house anti-aircraft guns.
After the war, the Allies demolished most of this monstrous bunker, but the northern wall, 42 metres high, was left standing, for fear that its blasting would ruin the rail tracks beneath it. One of the Underworlds tours takes visitors through the overgrown ruins of this forbidding structure and down into a seven-storey bunker.
Another tour visits the atomic fallout shelter at the subway station Pankstrasse, which is still fully equipped to house 3,346 people for several weeks. And the most popular tour shows visitors three successful and seven unsuccessful escape tunnels that were built from East to West Berlin, as well as some Geisterbahnhöfe - ghost train stations, located where West Berlin subway lines passed through East Berlin and which were heavily guarded to prevent defections.
For those who prefer to leave their heels on and stay above ground, there is a very civilized way to tour a Berlin bunker - thanks to Christian Boros, a public-relations magnate and art collector who last year converted one of Berlin's largest bunkers into a home for his art collection.
The Boros Collection, with roughly 500 works by the likes of Damian Hirst, Olafur Eliasson, Wolfgang Tillmans and Daniel Richter, is one of Berlin's most exciting collections of contemporary art.
As interesting as the art is the bunker in which it resides - its designer, Hitler's star architect, Albert Speer, considered it a work of art in its own right.
Located in the heart of Mitte, the Reichsbahnbunker Friedrichstrasse was built in 1942 as Allied bombing escalated. It was built to house 2,000 people - travellers through the nearby Friedrichstrasse train station, as well as visitors to the Deutsche Theater next door and local residents.
Designed to exude the Nazis' confidence of victory, the bunker featured marble cladding and magnificent spiral staircases.
After capitulation, the bunker was used by the Red Army as a jail. In East Germany, it became a storage facility for tropical fruits - with its two-metre-thick outer walls and sophisticated ventilation system, the "Banana Bunker," as East Berliners called it, served as a city block-sized fridge.
After the fall of the Wall, the bunker was claimed by Berlin's techno and fetish scene and enjoyed a reputation as home to Germany's "hardest" parties, which reached a pinnacle in 1995 with an event called Sexperimenta.
Boros spent five years restoring the place. A protected monument, this original structure, with its five storeys, hardened concrete walls, and Speerian flourishes, had to be maintained.
Many of the art pieces were commissioned for the spaces they occupy, such as Kris Martin's For Whom - a massive bell that swings silently over the visitors' entrance. Or Scandinavian artists Elmgreen and Dragset's hyper-realistic rubber figure of a man lying in a hospital bed, looking out one of the bunker's few windows, and giving guests to the hotel opposite a bit of a scare.
French writer Stendhal is said to have pondered in Berlin, "What could have possessed people to found a city in the middle of all this sand?"
Whatever possessed Berliners then seems to possess them still, with their determination to dig around and retrieve the history that is buried under and behind the city's formidable surfaces. Endorsed by the city's senate or not, Berlin's underworlds have been discovered and are eminently worth a visit.
Special to The Globe and Mail
* * *
If you go
Berlin Unterworld English-language tours require no advance reservations. Tours typically require sensible footwear, flashlights and subway tickets. www.berliner-unterwelten.de/guided-tours.3.1.html
Boros Collection Reinhardtstrasse 20; 49 (30) 2759 4065; www.sammlung-boros.de. Tours, available in English, are available only on weekends and must be booked in advance.