A 478-year-old bonsai olive tree in the front garden. An Andy Warhol Vesuvius screen print behind reception. Edo-era samurai armour and a glossy red baby grand in the lobby. Romeo Napoli, a glassy harbourfront hotel scored with steel "waves", is less a hotel than a very glamorous contemporary art gallery where you happen to sleep.

The location is the real headline act. Across a busy road sits medieval Castel Nuovo, then the industrial port — being spruced up for the 2027 America's Cup — and beyond that the aquamarine Bay of Naples, with Capri on one horizon and Vesuvius and Mount Somma on the other. The main ferry terminal, gateway to Capri, Ischia and the Amalfi Coast, is within walking distance, so island-hopping day trips are effortless.

The 10th-floor rooftop makes the most of it: a glass-walled infinity pool, sunbeds, and guests sipping Krug and cocktails (dress accordingly). If that's too public, there's a clubby cigar room with complimentary cigars, and downstairs a neon-lit La Spa Sisley Paris with salt room, multiple saunas, a steam room, chromotherapy lounge and a Kneipp walking pool lined with smooth river stones. Daily spa access comes with the room rate.

Harbour-facing rooms are the ones to book. Pull back the drapes, sink into a Poltrona Frau rocking chair and watch the ferries come and go. Interiors run to dark lacquered timber and mirrored, light-bouncing surfaces; some suites go full rock star with private saunas, steam rooms, gyms and even a Zen garden.

Food is a serious drawcard. Breakfast is served a la carte in Il Ristorante Alain Ducasse on the ninth floor, where floor-to-ceiling windows frame the bay and the spread runs to buffalo mozzarella, salume and sfogliatelle. Dinner is Michelin-starred Mediterranean fare in the same Ducasse restaurant; lunch and aperitivi happen up on the pool terrace.

Out the door, the historic centre is an easy walk, two metro stops are close by, the shopping-and-nightlife neighbourhood of Chiaia is nearby, and the National Archaeological Museum is about 20 minutes on foot.

Worth knowing before you go: rooms start at €555 a night including breakfast and spa access — this is a splurge, though the four-star review suggests it largely delivers. The check-in experience itself contrasts sharply with the beautiful chaos of Napoli Centrale station, where the review's writers arrived to jostling crowds and shouting taxi drivers. And brace yourself for the shower: the fittings are so baffling that staff offer new guests a tutorial.

For travellers who want big-city energy, serious art and one of the great waterfront views in Europe all in one address, Romeo Napoli is hard to beat — just budget accordingly and ask for the shower demo.