The plant was transformed into a stronghold in the Middle Ages, and later the structure was occupied by civilian homes; today it is possible to admire the grandeur almost in its entirety, on the back of the very central Church of San Pietro. The thermal plant was built in cement work, covered with a reddish brick curtain, and has a quadrangular plan, on which towers / buttresses rise in the corners.

The Baths were built on three floors, the first with the function of supporting the structure was used as a service environment; while the other two, consisting of large and airy rooms and large windows surmounted by arches, were decorated with mosaics and were used for spa activities, such as the frigidarium, the calidarium, the gym and other services. In some rooms of the thermal baths the exhibition space of the Museum of the Second Legion of Partica was created.