The thermal springs of Chaves have been drawing visitors since Roman times. The water emerges at 73 degrees Celsius from a geological fault line deep beneath the valley floor, heavily charged with sodium bicarbonate. The traditional cure here is drinking the water for digestive ailments rather than bathing in it — the spring fountains in the public garden are free to use, and locals fill bottles there daily.
The formal Termas de Chaves complex on the riverbank offers treatments in the modern spa, including hydrotherapy, massages, and the full range of traditional thermal procedures. Even if you skip the spa, the public fountains near the river are worth visiting: the slightly sulphurous, very hot water tastes medicinal in a way that feels genuinely ancient.