Raffles Europejski Warsaw

The most complete thermal circuit in Warsaw, and the only one that treats the sequence as the point. Raffles Spa runs sauna into hammam into experience showers into an ice fountain, with a counter-current pool to swim off whatever is left — the full hot-cold-hot loop, laid out so you actually use it in order rather than wandering between two warm boxes. The hotel around it is the restored 1857 Europejski on the Royal Route, which reopened as a Raffles with a serious art collection on the walls and service that reads the room. Access rides with the spa rather than the room key, so book it when you book the stay. If you only have one night in the city and want the heat to be the reason, this is the one.