About 2.5km from the city of Viterbo is the natural spring of Terme del Bullicame, are very ancient springs, also mentioned by Dante in the Divine Comedy. The Bullicame (formerly Bulicame) is a hot sulfur water spring (about 58 °C). The Bullicame is the best known of the many thermal and hypothermal springs fed by Viterbo's great hydrothermal basin, along with the other springs, Carletti, San Sisto; Bagnaccio, Zitelle, Piazza d'Armi, and many others. Since the end of the 20th century the spring has shown a gradual reduction in flow rate.
The Bullicame spring has been documented since the early Middle Ages as a crossing point along the Via Francigena. Particularly in the itinerary of Sigeric, Archbishop of Canterbury, it represented the sixth stage (Mansio) out of Rome and the location was called Sce Valentine, in memory of Saints Valentine and Hilary, who were martyred nearby, according to tradition.
