Orvieto stands on a tufa hill, overlooking the valley of Paglia river, a tributary of the Tiber. This enormous tufa mesa that rises twenty to fifty meters from the level of the country, is due to the collapse of ground by Quaternary volcanic system Volsinio, wreck in the caldera hosting the volcanic lake increased Europe, that of Bolsena.
The city founded by the Etruscans around the 8th century BC, and was an important Roman town, and during the Middle Ages and Renaissance.
The city preserves important monuments of all these periods:
-The Cathedral, a masterpiece of Italian Gothic architecture. The facade is decorated by a large number of bas-reliefs and sculptures made by the Sienese Lorenzo Maitani. Inside the of Chapel of San Brizio, famous cycle of frescoes on the Judgment by Luca Signorelli (1499-1502)
-The Church of San Domenico with the Mausoleum of Cardinal de Braye made by Arnolfo di Cambio
-The St. Patrick's Well is a historic structure built by Antonio da Sangallo the Younger, between 1527 and 1537, designed to provide water in the event of disaster or siege.
The access to the well, a masterpiece of engineering, is guaranteed by two-way spiral ramps, fully autonomous and served by two different ports, making it possible to carry with mules water extracted, unhindered and without having to resort to the only road leading to the town from the valley floor.
The Well, 53.15 meters deep has a cylindrical shape with a circular base with a diameter of 13 m.
There are 248 steps, and 70 windows that give light.