Berlin supporters seek permits to preserve Treehouse at the Wall
Supporters of Berlin’s Treehouse at the Wall are pressing to preserve the informal structure built by Turkish migrant worker Osman Kalin on former borderland in Kreuzberg. A district councillor says officials are working with Kalin’s son and the Turkish community on necessary permits, while structural safety, planning permission and ownership remain unresolved.
The story
Supporters of the Treehouse at the Wall in Berlin’s Kreuzberg district are seeking to prevent its possible demolition and to secure a future for the site through permits and public recognition. The two-storey, improvised structure grew from a garden established in 1983 by Osman Kalin, a Turkish worker who had arrived in West Germany in the late 1960s. Kalin cultivated a triangular piece of land beside the Berlin Wall that was physically in West Berlin but, because of the border’s alignment, officially belonged to East Germany. He later received permission from East German authorities to stay on condition that his building was no taller than the wall. Following reunification, Kalin faced eviction orders until the neighbouring St Thomas church identified documents supporting its ownership of the plot and permitted him to remain. After Kalin’s death in 2018, his son Mehmet maintained the property. The current dispute concerns the building’s structural condition, its lack of planning permission and unresolved ownership rights. Kreuzberg district councillor Florian Schmidt said his office was working with Mehmet Kalin and the Turkish community to obtain necessary permits; Mehmet has temporarily been allowed to undertake work. Supporters also plan an open-air exhibition about Kalin’s life on the fence around the site.
Why it matters
Keeping the treehouse would preserve a site that connects several histories often treated separately: the Berlin Wall, the postwar labour recruitment programme and the everyday use of neglected urban land. Its survival could give residents and visitors a concrete place to examine how Turkish workers shaped neighbourhoods such as Kreuzberg, rather than limiting that history to formal archives or memorial proposals. Conversely, demolition without a settled preservation arrangement could remove the structure that carries those overlapping stories. The case also tests whether an informal, community-maintained place can be made safe and lawful without losing the features supporters value.
Evidence and context
The Treehouse at the Wall sits in Kreuzberg beside the former Berlin Wall on a triangular plot whose border status left it effectively unused during the cold war. Osman Kalin, a Turkish worker who arrived in West Germany in the late 1960s, began cultivating the site in 1983 and later obtained permission from East German authorities to remain, provided his building did not exceed the wall’s height. Historian Stefan Zeppenfeld describes the structure as one of the few tangible legacies showing Turkish guest workers’ agency in Berlin’s cityscape. The debate therefore joins preservation of a physical remnant of division with recognition of migrants’ role in postwar Germany.
Limits and unknowns
The structure’s future is not settled. District councillor Florian Schmidt says use was initially prohibited because of the site’s unusual status and lack of planning permission, while ownership questions are still being clarified. Mehmet Kalin has received a temporary exemption to carry out work, but supporters’ wish to retain the building’s informal appearance must be reconciled with safety and legal requirements. The article does not establish a final permit decision, a preservation timetable, or what alterations may be required.
What happens next
Supporters plan an open-air exhibition using archival images and Kalin’s life story on the fence surrounding the structure. The key unresolved development is whether officials can grant permits while addressing safety, planning and ownership questions; the article places these discussions ahead of Berlin’s September election.
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Story timeline
Garden established
Osman Kalin began cultivating a former no man’s land plot beside the Berlin Wall.
Post-reunification dispute
After Berlin’s reunification, St Thomas church produced papers supporting its ownership of the land and allowed Kalin to remain.
Legacy continues
Osman Kalin died; his son Mehmet continued tending the property.
Berlin supporters seek permits to preserve Treehouse at the Wall
A short visual explainer for readers who want the story in a different rhythm.
Highlights
- Community and officials seek permits to save the Treehouse
- Osman Kalin’s Treehouse on former Berlin Wall land
- Local officials engage with Kalin’s family and community
- Exhibition planned to share Kalin’s story and legacy
Transcript
Supporters and officials collaborate to secure permits preserving the Treehouse at the Wall in Kreuzberg.
The Treehouse was built by Turkish worker Osman Kalin on a unique Cold War borderland plot.
Kreuzberg councillor works with Kalin’s son and Turkish community to address safety and ownership.
An open-air exhibition about Osman Kalin’s life will soon be displayed on the site’s fence.
Preserving the Treehouse connects histories of migration, urban life, and Berlin’s divided past.