Terme dei Papi (Viterbo)

The most famous thermal complex within day-trip range of Rome — natural sulphur springs in Viterbo, used since Roman and papal times (the name 'Terme dei Papi' means 'Baths of the Popes'). Centerpiece is a vast outdoor sulphur thermal pool fed by the Bullicame spring (referenced by Dante in the Divine Comedy). The natural cave grotto is a sweat-treatment chamber heated by volcanic vapours. About 1.5 hours from Rome by car or Cotral bus.