Roman Baths, Bath

The centrepiece is the Great Bath, a steaming green rectangle of mineral water open to the sky, ringed by a terrace of Victorian statues above the Roman stonework.

Below ground the route runs through the temple foundations, the heated rooms and the still-bubbling sacred spring, where the water rises hot from far underground.

The layering is the point: Roman engineering below, Georgian Bath above, and the whole city built in the same honey-coloured stone.

You cannot bathe in the Roman pools themselves, so this is a museum of water and engineering rather than a spa, though the modern Thermae Bath Spa next door uses the same hot spring for rooftop bathing today.

The bathing complex included a caldarium (hot pool), tepidarium (warm pool), frigidarium (cold plunge) and an open-air swimming pool called the gymnasium, with heated changing rooms and an exercising hall surrounding the sacred spring itself.

The mineral water that feeds the spring rises at 46 degrees Celsius and contains 43 different minerals, giving the water a slightly milky appearance and a mineral taste that 18th-century physicians prescribed for treating a wide range of conditions.

It is one of the best-preserved Roman religious and bathing sites north of the Alps, still fed by its natural hot spring.

The combination of genuine Roman remains with elegant 18th- and 19th-century additions tells the story of Bath as a resort across two thousand years.

It anchors a beautiful Georgian city that is itself a UNESCO World Heritage Site, easy to explore on foot.

The Roman Baths are one of the finest surviving ancient bathing complexes in the Roman world, their mineral-rich thermal spring flowing at a constant 46 degrees Celsius and feeding a sacred pool that has been used continuously for over 2,000 years.