Spina Piccola, included in the historical tour, is intact except for the wooden drawbridge, which was later replaced by a wall and designed to defend the barn, and the old citrus grove, complete with a special irrigation system which drew inspiration from the Middle East.

The tower, with a square base, built directly on the rock with carparo blocks, has a stern and dignified appearance. It is two stories high and is crowned with a slightly overhanging parapet.

Each opening is defended by a machicolation. The entrance arch, which opens onto the boundary wall, is surmounted by a machicolation which can be accessed by a double staircase set against the enclosure from the inside. On the same side of the “lama” (a torrential stream), towards Spina Piccola, there are two more caves in the citrus grove located within the walls of the tower. Here there is a third cave, which cannot be visited, as used as a cistern.

The latter cave is unusual because of its massive proportions with two central columns supporting the arches. Its original function is hard to ascertain because the cave was dug further to create a larger water reservoir. In addition, the walls are covered with a thick layer of "hydraulic mortar" which makes it watertight. It is assumed that it originally was used as a place of worship.