The Trou de Fer (“Iron Hole”) is a canyon on Reunion Island, off the coast of Madagascar in the Indian Ocean. The primary river flowing through the gorge is the Bras de Caverne River, a tributary of the Rivière du Mât. The canyon has two distinct parts: a large crater, which is fed by six prominent waterfalls, and a narrow slot canyon at its outlet, which constitutes most of the canyon’s length. The slot canyon, or “The Corridor”, extends for about 3 km (1.9 mi), and is said to be commonly dammed up by debris jams to form lakes, including the “Lake of the Eel”. Many springs flow through the porous volcanic rock of the walls, creating countless waterfalls.
By Jennifer_greatoutdoors (Flickr) [Public domain], via Wikimedia Commons