Osorno is a volcano of near-perfect symmetry standing 2,652 metres between two lakes in the Los Lagos region of southern Chile, capped with ice and doubled in the water on a windless morning, and at its foot the Petrohué River pours through chutes that the volcano's own lava carved, crossed on boardwalks through the forest. The cone is the picture of the Chilean lake district: from the shore at Ensenada, on Lake Llanquihue, it stands directly across the water like Fuji, and from the ski base on its flank a covered chairlift rises over slopes of black scoria and old snow to a lookout with both lakes and the volcanoes of the south in view. Above the lifts the mountain turns to bare glacier, and the crater is reached only with a guide, roped and in crampons, a long day on the ice. Charles Darwin, sailing with the Beagle, watched Osorno erupt at night in January 1835, and weeks later a huge earthquake levelled Concepción to the north; the volcano has been quiet since 1869.
The falls are the lava's work. An old flow from Osorno crossed the Petrohué and hardened into black basalt, and the river has cut through it into a maze of chutes and channels where the turquoise water, coloured by glacial flour from the lake above, races over the dark rock in a dozen falls at once; wooden walkways thread through the forest to overlooks above the water, with the cone standing over the whole scene. Behind the falls lies Todos los Santos, the emerald lake, with no road ever cut along it: a catamaran crosses its green length from Petrohué to Peulla, a settlement at the far end reached only by water, under the volcanoes of Osorno and Puntiagudo, and the same route carries on over the Andes to Argentina by lake and bus. Osorno is a volcano with a lake on either side, and the river between them is running over what the mountain threw down.