Also known as the tower on the Auser, the river that run along this portion of the walls, the Santa Maria tower, under which we see the homonymous gate, controlled access to the city and the passage of people and goods crossing the bridge over the river. In 1499, during the second Florentine siege, this tower was lowered to the height of the walls. Its leaning, visible from the outside, is remarkable and is even more accentuated following the reconstruction that took place around the mid-nineteenth century. The brick embattled crowning probably dates back to the same period. The tower is one of the entrances to the walkway on topm of the walls.