If there's one museum in Genoa you absolutely cannot skip, it's this one. The Galata Museo del Mare sits right at the Porto Antico and does something most museums fail to do — it actually makes history feel alive.
Spread across five floors, the museum takes you through six centuries of Ligurian seafaring, from the days when Genoa was one of the most powerful maritime republics in the world, through Christopher Columbus (who was born here, something Genoese people will remind you of constantly), all the way to the mass emigration waves of the 19th and 20th centuries. That last section hits harder than you'd expect — reconstructed ship cabins, personal stories, photographs. It's quietly devastating in the best way.
And then there's the submarine. Moored right outside the entrance, the S518 Nazario Sauro is a real decommissioned Italian Navy submarine you can actually climb through. Tight corridors, bunks the size of shelves, instruments everywhere. Even if you're not a history person, this alone is worth the visit.