A monument, composed of two overlapping parts, completely separate and oriented in different directions, dating back to different eras, was originally part of a villa, the presence of which is testified by archaeological remains located in the tuffaceous bank of the hill below and by semi-submerged fishponds in the water in front of it. According to one theory, the mansion passed from Ortensio to Antonia, wife of Druso, then to Nerone and, ultimately, to Vespasiano of the Flavian dynasty.
The upper building, located at a height of 3 m above the current ground level, is a large cistern from the imperial period, divided into four naves, with a barrel vault supported by three rows of pillars, one of which is a terrace, covered with a signinum floor. The room is dug into the tufa to a depth of 2 m and is covered with opus reticulatum masonry and tufa walling. Inside each vault are square inspection shafts, while in the north corner is a niche, visible through the plaster covering.
At a lower level, 6 m from the previous building, a system of water supply tunnels, dating back to the Republican period and only partially explored, was found. The latter, oriented East-South-East / West-South-West and arranged in an orthogonal manner, are about 4 m high, with a vaulted roof connected by narrow, low communication passages, covered with gabled tiles or flat roofing. The tunnels are excavated in tufa and lined with opus coementicium and cocciopesto, which shows that they were intended to function as cisterns. Even today, on the walls of these rooms, you can see the names of visitors from past centuries engraved in charcoal.