The Pozzo di San Patrizio is an ancient well in Orvieto, Umbria, central Italy, built between 1527 and 1537 at the behest of Pope Clement VII who had taken refuge at Orvieto during the sack of Rome. The cylindrical well plunges down more than 50 metres in a double helix design, which enabled donkeys to carry empty and full water vessels in downward and upward directions without obstruction.