Berlin keeps its wildest secret in plain sight: a forest the size of a small country, and a mountain made of its own ruins. Five kilometres of sand paths and pine, climbing to the strangest viewpoint in the city — the Cold War listening post the Americans left to the weeds.
Start at Grunewald station, but don't rush past the platform. Gleis 17 is a deportation memorial, and it earns a quiet minute before the trees. Then walk west into the Wald, where the paths go unmarked and the city noise drops away inside ten minutes. Aim for Teufelsberg — the Devil's Mountain — eighty metres of bombed Berlin bulldozed into a hill, topped by three derelict radomes now thick with graffiti. The station is privately run and gated; check the day before you set out. If it's shut, the Drachenberg next door gives you the same view for nothing.
From the heights, drop west toward the Havel — the Grunewaldturm for a coffee and a tower, then down to the shore at Schildhorn, where the river opens out and the sailboats lean. Follow the water north and climb to Heerstraße. One forest, one ruin, one river, and the train home.
