Located at the northern limits of the ancient city, the building is built in squared blocks of limestone worked with ashlar. It has two of arches, of which the standing orders of the lower order and some arches corresponding to the upper gallery. Remains of reticulated work are present in the corridors of the vomitories. The cavea is divided into four wedges and the bands in which the steps were not present probably welcomed wooden stairs.
The orchestra floor, paved with limestone slabs, allowed the collection of rainwater in a large cistern under the pulpitum. The frons scaenae has two quadrangular lateral niches and a central, semicircular one. Remains of the architectural decoration are kept in the Civic Museum (Palazzo dei Consoli). In the same museum there are also remains of an inscription from the Augustan period which refers to restorations carried out by the city magistrate Cneo Satrio Rufo who "... at his own expense he made the roof of the basilicas, fixed the roof beams with iron, made the floor of stone ... ".
 
The building used as an antiquarium, located near the Roman Theater, is a typical rural building of modest size, on two floors. During the consolidation works the remains of ancient masonry belonging to a very large Roman domus were found. The domus, occupied by the cottage, has an atrium, tablinum, kitchen, latrine and floorings in cocciopesto and mosaic. Inside the tablinum there is a mosaic floor with geometric decoration in black and white, of which only a few fragments, and in the center a tondo (emblem) with the polychrome depiction of Scylla in opus vermiculatum.
Given the importance of the mosaics and the Roman house, the 2D reconstruction was carried out which reproduces the geometric decoration of the mosaic carpet of the environment and the emblem with Scylla, of which only the central part is preserved. This operation constitutes an effective tool for understanding the floors, otherwise difficult, as they are very incomplete. The upper floor of the antiquarium was set up with archaeological material; an environment was intended for presentations and conferences.