Crypta Neapolitana

Also known as the Old Cave of Pozzuoli, it was built in the Augustan age by the freedman L. Cocceio Aucto, architect of Agrippa, admiral of Octavian, who, according to Strabo (V, 4, 6), was also the creator of the Portus Iulius, the "Cocceio Cave" and the Roman Crypta at Cumae.
Mentioned in the Tabula Peutingeriana (a map of late Imperial road routes) and mentioned not only by Strabo but also by Donatus, Seneca, Petronius and Eusebius, the tunnel is entirely excavated in the tufa over a length of 705 metres, an original width of 4.50 metres and a height of about 5 metres.

In 1806, under Joseph Bonaparte, two rows of lanterns were installed and kept permanently lit, while from the mid-19th century gas lanterns were used, one of which was found at the end of the century during recent restoration work. After the widening and lowering of the road surface and the paving works carried out in several stages by Alfonso of Aragon in 1455, by Don Pedro of Toledo in 1548, by Charles of Borbone in 1748 and by the Municipality of Naples in 1893, the cave lost much of its ancient appearance.
On either side of the entrance are two frescoed niches: the one on the left with a depiction of the Madonna and Child, dated to the 14th century, and the one on the right with the Face of the Almighty, of uncertain date. Petrarch, in his Itinerarium Syriacum, mentions a small chapel called Santa Maria dell'Idria, built by a hermit near the entrance to the cave.

During the Aragonese Restoration or the works carried out during the Spanish Viceroyalty, a white marble bas-relief depicting Mithras, dated between the end of the 3rd and the beginning of the 4th century AD, was found and is kept in the National Archaeological Museum in Naples. Evidence of the eastern god Mithras is known in Campania from the 2nd century AD, in contrast to the increasingly widespread Christianity; the presence of the relief in the Crypta has led to the hypothesis that we are dealing with a site of the Mithraic cult: the Mithraeum is usually identified with the spelaeum, the cosmic cave, inside which the sacrifice of the bull is depicted from the earliest iconographic evidence. It is probable that the mystery cults had a strong influence on popular superstition, which has always associated the cave with something mysterious and magical, to the point that simply passing through it unharmed was considered a real miracle.