To the south-west of the Canopus rise the immense substructions, 1755 feet in length, which supported the highest terrace on this side of the villa. They extend as far as the square tower called Rocca Bruna in Ligorio’s plan. This terrace and hill are supposed to have been the imitation of the Athenian Academy mentioned by Spartianus. There was a gymnasium here, the ruins of which are to be seen in a vineyard at the southern end of the hill, consisting of a large court, a circular temple, and a large recess. Beyond these there was a large square block of buildings supposed by Nibby to have been used for the students and masters of the School of Art maintained by Hadrian, and beyond this again was a spacious Odeum or theatre for musical performances. The raised seat of this is now converted into a vineyard, but the stage is still well preserved. There were, as in the Odeum of Catania, two divisions, and at the top of the central division was a round temple dedicated to the presiding genius of the Odeum; just as in the Theatre of Pompey the Chapel of Victory stood above the seats. Close to this Odeum are the vast subterranean passages supposed to be the Inferi which Spartianus mentions. The depth at which these lie is only fourteen feet, but they occupy a trapezoidal area, the longest side of which is about one thousand and fifty feet, and the shortest two hundred. Most of these corridors are excavated like catacombs in the natural rock. A brick stamped with the name Cynosarges was found near the aqueduct which runs to the south of the Inferi. There are two other names found in Spartianus, the Lyceum, and the Prytaneum, and Piranesi identifies the Lyceum with a ruined portico at a little distance to the south of the Inferi, and the Prytaneum with some more extensive ruins to the south-east.