The Buttes-Chaumont is the strangest of the big Paris parks — a cliff, a lake, a temple on an island, a waterfall in a cave — built by Haussmann's engineers in 1867 on top of a worked-out quarry and a former gibbet hill. But start higher, on the Butte-Bergeyre: a hill-village of five streets almost nobody finds.
Three kilometres, with real climbs. From Bolivar, take the steps up to Butte-Bergeyre — 1920s houses, gardens, a small working vineyard on the slope, and one gap in the buildings where Sacré-Cœur appears across the rooftops. Walk it in the morning, before the day fills in.
Then drop into the park proper. The Temple de la Sibylle sits on its cliff-island, copied from the one at Tivoli; reach it across the passerelle suspendue, the bouncing suspension bridge with Eiffel's office in its history. Below, the grotte hides a tall artificial waterfall in the old quarry mouth.
Climb back out the eastern side and exit at Botzaris, one stop from where you started.
