Thermae Bath Spa
Like Edinburgh's ONE Spa, the big draw here is a rooftop hydrotherapy pool, allowing you to do some fine bird's-eye sightseeing while you soak. The complex offers some of the most comprehensive spa facilities in the UK with a choice of pools, saunas, steam rooms and much more and the treatment list is equally broad. Try an aquatic treatment such as watsu if you really want to splash out.
6-8 Hot Bath Street, Bath, BA1 1UP
Treatments from £38 for 30 minutes, wahanda.com