The Peninsula New York

The Peninsula has been doing grand-hotel hospitality on Fifth Avenue for over a century, and its spa near the top of the building is a wonderfully old-school pleasure — a sunlit pool, a dry sauna, a steam room, and the kind of unhurried service that's increasingly rare. After your sweat you can drift up to the Salon de Ning rooftop for a drink, which feels like the correct order of operations. Rooms are classic, spacious, and quietly tech-forward in the Peninsula way. It's not the trendiest sauna in town, but it's one of the most reliably civilised — a proper hotel spa in a proper grand hotel, no gimmicks required. Guest access to the pool and heat is generally included; just confirm the spa's hours, which can shorten in the evenings.