Orvieto stands out on a tuff hill, showing off its jewels, first of all the wonderful Duomo. Under it, however, inside, another city is hidden and preserved, dug over the centuries through the volcanic rock. Walking through the streets of the city, we will discover two unique architectural jewels. The first is the Pozzo della Cava: this is a complex from the Etruscan era with various hypogeal environments and a well dug into the tuff rock on which the city rests. This has a depth of 36 meters and has unique features that we will discover in detail. The second stop of the visit that we will reach with a short walk is the famous Well of St. Patrick: this water structure dates back to the sixteenth century and had the dual function of water supply in case of disaster but also a refuge in case of attack. Designed by Antono da Sangallo il Giovane, it has the peculiarity of having a double staircase whose access is guaranteed by separate doors that allow for totally separate access flows. 54 meters deep, this engineering jewel will be the highlight of this exciting guided tour.