Several spaces dug on the tuff are still in place all around the whole Ardea area. They form a complicated network of galleries which extend in all directions and come out all inside the crags characterizing the Acropolis.
This tunnel system constituted the water and sewer mains of the town, with the function of water draining and irrigation.
They date from VI-IVth Century before Christ and represent an excellent hydraulic engineering work, still functioning. Other spaces, dug on the tuff and clearly visible on the right side walking up to the Rocca, were devoted to warehouses for the preservation of the wheat and other foodstuffs. Large underground cavities, divided into aisles by means of tuff pillars, were cisterns for the preservation of the water.
