Araucaria forests
Ancient Andean trees.
Ayi.funes — CC BY-SA 4.0 · Balon Greyjoy — CC0 · Ayi.funes — CC BY-SA 4.0 · Andarin2 — CC BY-SA 3.0 · Balon Greyjoy — CC BY-SA 3.0
Lake Caviahue, also called Lago Agrio, «Sour Lake», is one of the few naturally acidic lakes in the world, because the Agrio river brings it the volcano's sulphurous water. It fills a wide, horseshoe-shaped old volcanic caldera of about 9 square kilometres, surrounded by steppe and forests of araucaria, the ancient Andean tree with symmetrical branches. Caviahue village sits on its shore at 1,600 metres, with ski slopes above it in winter and the steaming Copahue volcano behind. Nineteen kilometres away by gravel road, at 2,100 metres, lies the thermal village of Copahue, known for its mud pools and sulphur waters, open only in the warm season, from November to early May. Both names come from the Mapuche language: Caviahue, «place of celebration or meeting», and Copahue, «place of sulphur». Copahue volcano is active and monitored, so check the official alert level before you go.
Ancient Andean trees.
Steaming above.
A lake in a crater.
Caviahue village, Ñorquín department, northwest Neuquén
Only in the warm season, November to early May, 19 km from Caviahue by gravel road.