Not to be confused with Grotta Seiano (cave of Sejanus) in Posillipo.
The Crypta Neapolitana[1] (Latin for "Neapolitan crypt") is an ancient Roman road tunnel near Naples, Italy. It was built in 37 BC and is over 700 metres long.
^Crypta Neapolitana (Naples, Italy), A Multidisciplinary Underground Heritage Site
Graziano Ferrari1, Raffaella Lamagna1, Elena Rognoni1, Hypogea 2019 – Proceedings Of International Congress Of Speleology in Artificial Cavities – Dobrich, MAY 20-25 2019