The conservation restoration of a seventeenth-century building of communal property, has allowed to bring to light structures of imperial age. They are kept for about 15 m of height corresponding to four floors: two below the current level, 9 m deep, and two above ground. It is a large complex of structures, whose first phase consists of two-storey rooms, covered with barrel vault, arranged to rack on narrow service roads parallel to the course of the river and around courtyards.
The rooms was part of a vast complex of warehouses built in an area that in the last decades of I century a.C. It held a commercial district, perhaps the Horrea Vespasiani, whom Domitian had built in this area along the river. The buildings underwent a total restructuring at the beginning of the third century. a.D. with the insertion of large rooms, other warehouses and houses of dwellings, raising the level up to at least the four floors of height. The whole complex underwent a further reconstruction following a fire (probably the one that occurred in 283) that had caused damage to all the structures. At this stage, of the Constantinian age (first decades of the fourth century), belongs the compaction of the ground floor and the strengthening of the walls which were lined by other structures in order to triple, in some cases, the thickness.
Some rooms of the complex have black and white mosaic floors decorated with geometric motifs that are an example of the popular mosaic repertoire in Rome during the ancient age.