When the 3rd-century-B.C. Etruscans needed water, they sank a 5.4m-wide (18-ft.) shaft more than 35m (115 ft.) into the pebbly soil under Perugia. To support the cover over the well, they built two massive trusses of travertine that have stood the test of more than 2,000 years. You can climb down past the dripping, moss-smothered walls to a bridge across the bottom.