The cavity opens on Vittorio Veneto Street, opposite house number 40. The wide entrance is entirely obliterated by a double stone wall in which small doors not in axis with each other have been spared. Irregular in shape, the cavity has a perimeter of about 150 meters and an internal development of about 800 square meters. Half of the cavity is developed on an irregularly diamond-shaped debris cone, the other half on a flat surface created by topsoil, which, however, does not represent the original floor of the cavity. The subterranean environment arose from quarrying activities: five squat pillars with a square base were spared in the rock during excavation to give solidity to the vault and prevent collapse, while traces of a sixth pillar, removed later, are recognizable in the vault. Once the quarrying activity ceased, that of use as a water reservoir probably followed. Such use, in the opinion of Canon Giovanni Spano, would have begun in Carthaginian times and continued in Roman times. No waterproofing mortar is currently noted on the walls of the cavity, but there may have been in ancient times, or still be in the parts covered with debris.
In 1943, during World War II, the cavity was reused as a shelter against bombing and a rudimentary electrical system was also built inside. When the war ended, the cave gave precarious shelter for some time to those evacuees who, upon their return to Cagliari, found their homes destroyed by bombing.
It is the work of the last few decades to fix up Vittorio Veneto Street and demolish some dilapidated houses leaning against the outer wall of the cavity.
