The city of Bath, 115 miles west of London, derives its identity from the hot mineral springs where groundwater bubbles to the surface at a temperature of 115 degrees Fahrenheit. The springs were long venerated by ancient Britons, and were discovered in turn by invading Romans in a.d. 43. The Romans were quick to exploit the potential of this riverside site surrounded by steep wooded hills, establishing the great public bath that is still to be found here. The city took on much of its present homogeneous form, however, over a short period in the 18th century when Bath became a fashionable spa resort, largely designed by architects John Wood the elder and younger. But the Georgian baths from that era had fallen into disuse by the end of the 20th century. By 1997, city leaders—ever cognizant of Bath’s status as a UNESCO World Heritage Site—were considering radical new approaches to revive the spas.

Grimshaw won an invited competition to build a new spa building as part of a larger project involving the restoration of the adjacent 1775 Hot Bath by Wood the younger, and the exquisite 1790 Cross Bath by Thomas Baldwin, both at the city’s center. To exploit the hot mineral springs, the new site had to be very close to these existing buildings. Construction was made possible by the demolition of the 1927 Beau Street swimming pool, an unused building of little merit. The aim of the project was nothing less than to reestablish Bath as a leading center for spa activities—sybaritic bathing, body conditioning, and aquatherapy—for the first time in more than 25 years. As a remarkably ambitious project of national importance, it was funded in part by the British government’s Millennium Commission.