As I get my shoulders under the warm mineral waters of the rooftop pool at the Bath Spa Thermae, it’s easy to see why so many period films and TV shows are filmed in Bath – there’s barely a 21st-century addition in sight. Higgledy-piggledy roofs dotted with stubby chimney stacks sit atop limestone Georgian houses, and with its seven surrounding hills in the near distance, I get a great sense of just how compact this World Heritage city is. I’m visiting with a group of girlfriends and an afternoon at the Bath Spa Thermae is highly recommended. From £38 for two hours of access to not just its rooftop pool but a series of saunas and steam rooms plus a larger thermal pool, we’re taking in the same mineral-rich waters as the Celts and Romans did over 2,000 years ago.