On the bay's southwestern promontory is the fascinating Grotta di ?­Nettuno (Neptune's Grotto).
Neptune's Grotto was built on the promontory in the first century BC.
mnli hypothesis: Neptune's Grotto was built on the promontory in the first century BC. premise: On the bay's southwestern promontory is the fascinating Grotta di ?­Nettuno (Neptune's Grotto).