It is the medieval gateway to Civita on the Bagnoregio side and is named Santa Maria for the nearby church dedicated to the Madonna. In the past it was also known as Porta Cava because the original Etruscan gate had been excavated in the tuff.
On the walls, crosses are scratched into triangles probably made by pilgrims returning from the Holy Land or by Templars as a reminder of the cross of Golgotha in Jerusalem. On the sides of the door there are two bas-relief sculptures reminiscent of the victorious popular revolt of the inhabitants of Civita against the Orvieto family of the Monaldeschi of 1457. The sculptures are of a lion holding a human head in its claws. The door is the only one left of the two once existing.