Terme dei Papi
Viterbo has been a spa town for centuries, and this excellent complex just a few miles outside the town walls continues the tradition, providing health and beauty treatments with an Etruscan twist: try a facial with local volcanic mud or a steam bath in an ancient cave. The main draw, however, is the 21,000-square-foot outdoor limestone pool, into which Viterbo's famous 59°C (138°F) mineral water pours—and gives a jolt with its sulfurous odor.
You can rent floats and deck chairs, but you'll need your own bathrobe and towel unless you're staying the night at the spa hotel. Day passes tend to sell out but can be booked online up to five days ahead of your visit.
