This is where the city began. The legend has King Vakhtang's falcon and a hot spring; the geology has the same warm, sulfur-rich water rising from beneath the rock, and it has never stopped. The bathhouse quarter, Abanotubani, grew up around it, and its low brick domes — the roofs of bath chambers sunk into the ground — are among the oldest sights in Tbilisi.
Behind them stands the prettiest of the baths, the Orbeliani, its façade a sweep of blue tile and pointed arches borrowed from Persia. Inside, you take a private room by the hour: a deep pool of mineral-warm water, a marble slab, and, if you ask for it, an attendant who will scrub you with a rough mitt and wrap you in mountains of soap foam. You emerge pink, loose-limbed, and faintly smelling of the earth.
Travellers have been writing home about this for two centuries. Pushkin called the baths the finest he had known; Alexandre Dumas came and marvelled. The ritual has barely changed since.
Go in the evening, after a day on your feet. Book a private room rather than the public hall, add the scrub, and plan to do very little afterwards. The concierge can reserve a room and a time.