Osorno Volcano last erupted in 1869, but its most talked-about eruption came in 1835, when a young Charles Darwin watched it glow through the night from the deck of HMS Beagle. Rising 2,652 metres in a snow-covered cone so symmetrical that Chileans call it the Fuji of the Andes, Osorno stands between two lakes in Vicente Pérez Rosales, the oldest national park in Chile, protected since 1926. Its slopes fall in reddish volcanic sand and lenga forest to the shore of vast Llanquihue Lake, where on a settled day the whole cone doubles in the water. The jagged spire of Puntiagudo and the broad hump of Calbuco close the horizon, and the same lava that raised this landscape also blocked and shaped the rivers below.
Just east, the Petrohué Falls mark the point where the outflow of Todos los Santos Lake is forced through narrow channels of black basalt that Osorno's lava laid down thousands of years ago. Glacier-fed water runs a milky green through the dark rock, and the roar carries far downriver. Wooden walkways lead out over the chutes, close enough to feel the cold spray. Higher up, a chairlift climbs the volcano's flank to wide views across the lakes and neighbouring peaks, while boats cross the emerald water of Todos los Santos on the historic Andean route toward Bariloche in Argentina. All of it lies within easy reach of Puerto Varas, the lakeside town that has served as the gateway to this corner of the Lake District for well over a century.