Tsingy de Bemaraha is a forest made of stone in western Madagascar, a plateau of grey limestone that rain has cut into thousands of needles up to sixty metres tall, so close together and so sharp that the Malagasy name means the place where one cannot walk barefoot. You walk it in a harness. Steel cables run through the maze, and the route threads between the blades, climbs bolted ladders up the pinnacles and edges over footbridges strung across the gaps, with the drop into the crevasses below your boots and the tips of the stone at eye level; the edges are fine enough to cut skin, and nobody touches them. Stop at a single pinnacle and you see what the water did: fine parallel flutes and knife edges scored into the limestone by rain running down it for millions of years, and below, in the cracks, a green world of forest that never sees the sun.
The stone is full of life that exists nowhere else. More than eighty percent of the plants and animals here are found only in Madagascar, and many of them only in this one band of limestone, each crevice its own climate: dry scrub on the sunlit tops, wet forest in the shaded depths a few metres away. The best-known is the Decken's sifaka, a white lemur with a bare black face that leaps clean across pinnacles which would open human skin, landing sure-footed on stone too sharp to touch. Below the plateau the Manambolo river has cut a gorge through the same rock, and a dugout pirogue glides down its ochre water between sheer grey walls, past caves that hold the burial sites of the Vazimba, some of the earliest people of Madagascar, kept fady, sacred and strictly off-limits. The tsingy is reached only in the dry season, at the end of a long dirt road and a river crossing, and few places on Earth are this hard to get to and this hard to walk on. The stone forest was made by water, and it is water that still keeps it sharp.