The aim of the present study was to investigate the greatest water reservoirs in the ancient Roman world and, in particular, the “Piscina Mirabilis” in Misenum, in Southern Italy. In our study, we considered the reservoirs with a volume in the order of thousands of cubic metres, storing flowing water, set low in the ground or actually underground, and roofed over. In general, a Roman aqueduct was not built to provide drinking water, nor to promote hygiene, but either to supply the baths or for military aims. As a matter of fact, the population of Rome at the end of the 1st century AD had an average water supply of 1,550 L/d per capita especially used for baths. This circumstance required reservoirs of huge capacity. The reservoir of the Baths of Caracalla in Rome could contain over 80,000 m3 of water. The use of columns in a Roman reservoir was introduced in the ancient Constantinopolis and the Yerebatan Saray with a maximum capacity of almost 85,000 cubic metres can be considered the biggest Roman reservoir. While for military aims, the Piscina Mirabilis in Misenum can be considered the biggest Roman resevoirs used for military aims ever known until now (provide the Classis Praetoria Misenensis) with a volumetric capacity of 12,600 m3 of water.
Keywords: Miseno, Naples, Piscina Mirabilis, Roman aqueduct, Serino