Two pools in the tiny village of Baños Morales, where the Morales and Volcán rivers meet, are pleasantly warm, not hot, and rich in iodine and other minerals. You can hike from this area as well. Be warned that surprise winter storms can trap you here. The village has some rustic lodging, but many people prefer to come for the day.
Camino Cajón del Maipo, 92 km (57 miles) from Santiago, Villa Baños Morales, 9460000, Chile