As the sun sets across the Georgian rooftops of Bath, there is no finer place to be than wallowing in the steamy warmth of the rooftop pool at Thermae Bath Spa. It is the lone location in Britain where visitors can escape into spring water that is naturally heated. Hotel spas, even in Bath, make do with warmed tap water. Thermae uses mineral-rich spring water bubbling up from the limestone at 113 deg F—just like the Romans who built the intricate bathing complex that still stands a few hundred yards away.
There is a modern sense of luxury within the modern construction. More than 140 architects competed to win the contract. Nicholas Grimshaw’s winning design uses conventional Bath stone, like the Georgian buildings surrounding the spa, plus giant swaths of glass and idiosyncratic round portholes. This building also accommodates the Minerva Bath, the largest and most futuristically stylized of the three on offer, with massage jets, a whirlpool, and a “lazy river.”
The customary treatments are available, as well as private escapes to the restored Georgian Hot Bath and the secluded Cross Bath, a stand-alone bathhouse across the street built above the site of the original Roman cistern. At the main three-story spa, there is everything a latter-day Roman bather could want: scented steam saunas in circular glass pods, an indoor pool with gently flowing currents, bubbling foot baths, a huge shower big enough to soak a dozen people at once, and the highlight, a rooftop pool. The naturally heated rooftop pool on the spa’s New Royal Bath building is best enjoyed at night, when the skyline is floodlit. Visitors can take in a panorama that includes the ornate towers of 17th-century Bath Abbey in the center of town.