The curative properties of the Aurelia spring, over which rises the thermal centre of San Carlo, were probably known already in Roman times. The Baths are named for Saint Carlo Borromeo, Bishop of Milan, who came here in the second half of the 16th century to drink the water from the spring as a cure for kidney stones.

Active since the 1930s, but completely rebuilt in 1992, the Baths are still today renowned for mineral water therapies and for the direct bottling of the mineral water that gushes from the spring at a temperature of 12°C.