You can reach the Giacatello hypogeum from a path that opens on the side of the main road north of the parking lot of the San Nicola Museum. The hypogeum consists of a vast quadrangular environment (20 × 20 m approximately) with a height of just over 2 meters and supported by 49 pillars arranged in several rows. The roof has twelve openings almost all communicating with the outside, with the function of wells for drawing water.
An aqueduct flows into it from the north-west, while a tortuous tunnel departs from the south-east corner, which flows into the nearby stream of S. Leone. Originally it was a cistern belonging to the complex network of aqueducts of Akragas which, according to tradition, was designed by the architect Feace and built with the labor of the Carthaginian prisoners defeated in Himera in 480 BC.
The structure was transformed into a grain warehouse in Roman times.