Thermal Tradition of Caldes de Montbui Curiosity · Caldes de Montbui, Vallès Oriental, Barcelona Image of Caldes de Montbui, not of the place itself. Font de la Teula and other hot-water springs exploited since Roman times, among the hottest in Europe, with outflows reaching 74°C; the waters are sodium chloride and carbonate in composition, recommended for rheumatic and respiratory ailments and stress. The Romans called the place Aquae Calidae and built baths there that retain a 2nd-century vaporarium, among the best preserved on the peninsula. Photo: Viquipèdia / Wikimedia Commons (CC BY-SA) What to see and do in Caldes de Montbui