Parc des Buttes-Chaumont is the only Paris park cut and moulded out of a quarry, and the cliffs are still bare rock with paths running across their faces. A lake fills the bottom. A rock island rises thirty metres out of the water with a small round temple on top, copied from one at Tivoli near Rome. Two bridges lead across, but the island and both bridges are fenced off. The park is a hill, so every path climbs, and the western slopes give long views toward Montmartre.
The hill here had been mined for gypsum until it was hollow, and the surface was left as a rubbish tip and a yard where dead horses were cut up. In 1864 the state handed the ground to Jean-Charles Alphand, the engineer running Napoleon III's park programme, and told him to have it open in time for the world's fair. His crews blasted the quarry face into cliffs, moved two hundred thousand cubic metres of earth, dammed a lake and planted the whole thing. It opened in 1867. A cave under the cliff is the mouth of the old quarry, left open on purpose.