This 45m-high (148-ft.) civic project from the late 13th century was built to keep on eye on Orvietan territory. In the 19th century it served as a main cistern for the city's new aqueduct system, then became the bell-ringing communal timekeeper when a mechanical clock was installed in 1876. You can clamber up for a sweeping view of the city and, on clear days, the countryside as far as Mts. Cetona and Amiata. If you don't fancy climbing all 236 steps, a lift whizzes you up the first 100 or so.