A home-made home (with tree attached)
In 1983, when the Berlin Wall was still standing, Osman Kalin decided to make use of a small strip of derelict land that lay directly beside it.
Although officially belonging to the GDR, it was physically located in West German territory simply because the wall had not been curved to accommodate a tiny bend in the border.
Herr Kalin used the land to create a garden, and built a small hut, too, ingeniously constructed out of scrap materials.
The DIY abode initially aroused the suspicion of East German border guards, who visited him several times to inspect his handiwork, but he was allowed to continue unhindered.
The hut grew in size and complexity, with extra space built right around a tree that already grew on the plot. From then on, it became known as the 'Baumhaus an der Mauer', or treehouse on the wall.
When the Wall fell in 1989, and Kalin's home was threatened with demolition, locals supported him in a bid to save the property.
Surrounded now by roads rather than overshadowed by a grim concrete barrier, it nevertheless retains its former name as a place 'on the wall' - a remarkably robust recycled cottage and unlikely urban oasis with a history mirroring that of the city itself.
Baumhaus an der Mauer (Treehouse on the Wall): Bethaniendamm 23, 10997 Berlin (approximate address; adjacent to the Sankt Michael Church)