More than just about any other town, Orvieto has grown from its own foundations. The Etruscans, the Romans, and those who followed dug into the tufa (the same soft volcanic rock from which catacombs were made) to create more than 1,000 separate cisterns, caves, secret passages, storage areas, and production areas for wine and olive oil. Much of the tufa removed was used as building blocks for the city that exists today, and some was partly ground into pozzolana,
which was made into mortar. You can see the labyrinth of dugout chambers beneath the city on the Orvieto Underground tour (Orvieto tourism office, Piazza del Duomo 24, 0763/341772) run daily at 11, 12:15, 4, and 5:15. Admission for the hour-long English tour is €6.
Pozzo della Cava. If you're short on time but want a quick look at the cisterns and caves beneath the city, head for the Pozzo della Cava, an Etruscan well for spring water. Via della Cava 28, 05018. 0763/342373. €3. Tues.–Fri., 9–8.