The treehouse that defied the Berlin Wall

The “Baumhaus an der Mauer”, or the Treehouse on the Wall, was erected by Osman Kalin, a Turkish migrant worker, in the 1980s.
The “Baumhaus an der Mauer”, or the Treehouse on the Wall, was erected by Osman Kalin, a Turkish migrant worker, in the 1980s. screengrab, France 24

The “Baumhaus an der Mauer”, or the Treehouse on the Wall, was erected by a Turkish migrant worker in the 1980s along the Berlin Wall and continues to be an important memento, 30 years after the reunification of East and West Germany.


If you want to find Berlin's Treehouse on the Wall, go to Bethaniendamm passage 0, not far from the Spree, bordering the districts of Kreuzberg and Mitte: An imaginary address for a very real place, which, since the fall of the Wall, has become a symbol of the city’s reunification.

The address was purposely created by the municipality because the “Baumhaus”, as it is affectionately known to Berliners, is the only house to have been built along the Wall in the middle of a no-man’s land, back in the time when Berlin was still divided in two.

A green oasis in the shadow of the wall

It’s easy to miss this odd little two-storey construction, nestled in between two trees, overlooking a small garden. The imposing façade of Saint Thomas Church across the way attracts much more attention. But Berliners know it well. 

The house’s story dates to the beginning of the 1980s. Built entirely of recycled scrap materials, it was erected by Osman Kalin, a Turkish immigrant who died last year at age 92. Kalin took advantage of a deviation in the Wall’s route to carve out his own little green space.

At that particular section of Bethaniendamm, East German workers had to build a right angle into the wall to accommodate the official plans. Pressed for time and looking to save money, they left a small strip of fallow land. It was on this 350-square-metre plot, legally under the jurisdiction of the German Democratic Republic (or GDR, as East Germany was officially known) but on West German land, that Kalin set his sights.

He was not intimidated by the police patrolling with their dogs, the armed guards at their border posts or the morbid atmosphere pervading the area, often the scene of escape attempts and violence. Looking for a hobby to fill his free time, he decided to turn the vacant lot into a vegetable garden.

“In order to understand what motivated him, you mustn't forget where he came from: He brought with him the rules and culture of the village where he grew up. He couldn’t understand why no one would want to fix up a neglected place or try to turn it into a welcoming place for everyone. He didn’t care about the Wall or the guards,” said Funda Kalin, Osman’s granddaughter, who still lives in Berlin.

His project did not go unnoticed. “Of course it caused problems in the beginning. The East German guards quickly came over to make sure that he wasn’t digging a tunnel under the garden to help East Berliners get to the West,” she said. “But when they understood that it was simply a vegetable garden, they left him alone.”

Then the West German police officers asked him to leave, but he refused. Since the garden was officially under East Germany’s jurisdiction, the West Berlin authorities couldn’t intervene. And the GDR police officers, noticing that their Western counterparts were annoyed by this stubborn Turk, took pleasure in giving him free rein.

Onions for wine

The house’s actual construction, which began in 1982, posed more of a problem. At first Kalin could only build a small cabin because the GDR did not allow construction higher than the Wall. Kalin accepted this restriction as long as he could continue working in his garden, where he planted mostly onions and garlic. He didn’t live there; the Baumhaus was always merely “the Turkish equivalent of a workers' garden”, Funda Kalin said.

Osman Kalin started his garden on a small strip of fallow land created during the construction of the wall.
Osman Kalin started his garden on a small strip of fallow land created during the construction of the wall. screengrab, France 24

As the months went by, the border guards and the Turkish immigrant settled into a peaceful coexistence. He greeted them every day and gave them onions. For the end-of-year holidays the soldiers sometimes gave him bottles of wine, which Kalin, a practicing Muslim, politely set aside.

Kalin was finally able to expand his house after reunification, still using exclusively recycled scrap materials. The house has running water, electricity, an office and a bedroom. “We spent a huge amount of time in this house. We used to celebrate birthdays and have barbecues in the garden,” Funda Kalin recalled. She remembered how astonished passersby would watch as they enjoyed themselves in this house that didn’t look like much of anything.

It took some time for Berliners to rediscover the extraordinary story of the Baumhaus and turn it into a symbol of resistance to the Cold War's established order.

Funda Kalin, now 34, became aware of the importance of her grandfather’s house during a history of architecture class when she was 17. “The teacher was showing us slides of important constructions, such as the Brandenburg Gate, the Louvre or the Eiffel Tower – and suddenly I saw a picture of our house,” she recounted. Her classmates began to protest, “saying that it was a vagrant's house, but my teacher told them the whole story and I understood that our vision of the house was evolving”, she said.

Today there is talk of turning it into an official monument attached to the Berlin Wall Memorial, or even into a private museum. In any case, the Baumhaus looks set to hold its ground for the foreseeable future. A few years ago, real estate developers tried to build a housing project there, but a massive mobilisation of local residents quickly derailed that plan.

This article was adapted from the original in French.

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