Beneath a cloak of rock where an ancient pozzolanic cave could once be found, the cryptoporticus is hidden, an artificial circular nymphaeum marked with large niches containing classical statues originating from the excavations at Pompeii and Herculaneum and from the Farnese collection. In its vault, the structure has artificial gaps which allow the thick vegetation of the area to penetrate, evoking Romantic emotions of discovery.