Naples National Archaeological Museum

The MANN is the second half of Pompeii. The site gives you scale and street plan; this building holds what the ash preserved — the Alexander mosaic from the House of the Faun, the bronzes from the Villa of the Papyri, and the Farnese sculptures on a scale that stops conversation.

For a reader on a port call it is also the answer to bad weather and brutal heat: air-conditioned, dense and walkable in two hours. The Secret Cabinet keeps its own access hours — check them at the desk on arrival.