Baiae, Rome Beneath the Bay

The account

Baiae was where Rome went to misbehave, Caesar, Nero, and Hadrian kept villas on this volcanic shore. Then the bradyseism that built the coast let it down, gently, into the sea. Today the nymphaeum statues stand in four metres of green light and mosaics roll out under a diver's hands. The whole resort is an underwater park: shallow enough to snorkel, rich enough to dive for a week.

Leads, where the trail points now

• Pin down the most specific last-known position in the record before going; the search centers on Gulf of Pozzuoli, Naples, Italy.
• What you are chasing is Mosaic floors, marble statues, an emperor's pleasure villas. Work the documented record of Baiae, Rome Beneath the Bay back to primary sources and separate what is attested from folklore.
• Submerged Archaeological Park of Baia, dive and snorkel with authorized guides (max 8 per group); touching and removal forbidden.