Italian legend has it that the ancient god Saturn was fed up with feuding villagers and threw a flash of lightning into a volcano crater, causing a gush of warm water to envelop the land and calm its people. That spot is now the source for the luxurious Saturnia thermal spa in Tuscany, where 37-degree water still flows. Throughout Italy, thermal springs have been used to promote wellness since Etruscan times, when nobles and commoners alike soaked in communal baths. Today the best way to enjoy Italy's natural springs is to check in to one of the lush spas.
Terme di Saturnia's water flows into four picturesque outdoor thermal pools, where visitors can bathe year round. Check in to the spa's hotel for a weeklong wellness-immersion program (from €2,500 per person; termedisaturnia.it). The sulfur springs of Viterbo were popular with popes and local poets and artists like Dante and Michelangelo. Today visitors to the Terme dei Papi spa can bathe in the 2,000-square-meter outdoor pool or partake in treatments including Watsu warm–water and ayurvedic massages (from €900 for a week of treatments; www.termedeipapi.it).
The volcanic island of Ischia is well known for its radioactive mud, used for centuries to treat arthritis. The Mezzatorre offers three-day spa getaways starting at €1,035 per person, as well as a seven-day anti-aging program that includes Thalasso treatments and a full-body radioactive-mud mask (from €1,650 per person; mezzatorre.it).