The Roman cisterns
The great Roman cisterns are considered an authentic patrimony of the hydraulic art of the Augustan age, as well as an ingenious idea of Vitruvius. Almost certainly it was decided to create what are commonly called purifying or filing pools to respond to a water need that would otherwise not be fulfilled. The large underground complex, datable to the end of the 1st century BC, is unique in Italy by extension (approximately 2200 m2). Three tanks were built for storage and subsequent supply, arranged on the Girfalco, in the current largo Temistocle Calzecchi Onesti and in via degli Aceti which obviously were at different heights. The first is currently not open to the public because it is completely underground, while the second, known as small cisterns, is. Its flow rate is less than that of the reservoir located in via degli Aceti, which however from a strictly structural point of view does not present significant differences compared to the smaller one. The interior consists of thirty rooms divided into three rows, each of which has a masonry covered with opus signinum or cocciopesto which, as Vitruvius writes, was mainly used in the manufacture of cisterns, aqueducts, thermal pools because they are suitable for waterproofing the mortar. lime. It is very suggestive to come across obsolete writings such as "Calma, exit", dating back to the Second World War, when the rooms were used as a refuge against bombing.