Short answers, pulled from the story.
The Roman Baths are well-preserved Roman thermae, or bathing complex, in the city of Bath, Somerset, England, built around a natural hot spring. The site is preserved today in four main features: the Sacred Spring, the Roman Temple, the Roman Bath House, and a museum holding artefacts from Aquae Sulis.
Visitors cannot enter the water because it carries Naegleria fowleri, a deadly pathogen. In October 1978, a young girl swimming in the nearby Beau Street baths, fed by the same spring complex, contracted naegleriasis and died, which led to the baths' closure for several years.
The Roman Baths, together with the Grand Pump Room, receive more than 1 million visitors annually, making it a major tourist attraction in the UK.
The site's springs were dedicated to the goddess Sulis, who the Romans identified with their own goddess Minerva. The Roman settlement that grew up around the springs became known as Aquae Sulis, meaning the waters of Sulis.
The water begins as rainfall on the nearby Mendip Hills. It percolates through limestone aquifers to a depth of between 2,700 and 4,300 metres, where geothermal energy heats it to between 69 and 96 degrees Celsius, before rising back to the surface through the Pennyquick fault.
The temple was constructed between 60 and 70 AD, in the first few decades of Roman Britain. The wider bathing complex was then built up gradually over the following three hundred years.