The Aula Ottagona (Octagon Room) is part of the Roman National Museum network and was once used as a minor frigidarium. It was originally decorated with marble and stucco, although these are no longer visible. Visitors can see displays of marble and bronze sculptures which were the type of art works that once decorated the great Roman thermal baths from the 2nd to the 4th Century A.D. and covers the period of the Diocletian Thermal baths to that of Caracalla and Constantine.