At the bottom of a long, steep and exhausting descent, the Grotta di Seiano is not, in fact, a cave but a 1st-century tunnel linking the Roman Villa Pausilypon to Pozzuoli. Ventilated by three air ducts opening onto the sea, it was dug out of the tufa rock by Cocceius, the same Roman engineer who built the Crypta Neapolitana in Parco Vergiliano . When the villa's owner Publio Vedio Pollione died in 15 BC, he bequeathed his clifftop pad to friend and emperor, Augustus.
