In A.D. 75, the Romans channeled Bath’s hot mineral springs into a luxurious bathing complex that rivaled the baths in Rome. They're as impressive today, though there's no longer any bathing going on here. Instead, visitors stand on a viewing platform overlooking the large pool where legionnaires once soaked in waters that continue to bubble forth at 116°F (47°C), at the rate of about 240,000 gallons a day. In a maze of subterranean chambers, which you navigate with the aid of a terrific self-guided audio tour, are the remains of steaming pools and saunas, surrounded by elaborate paving. The visit is augmented by intriguing videos showing ancient construction techniques and a ghostly projection of Roman bathers beside one of the pools. You can sip the famous waters in the adjacent 18th-century Pump Room (free with admission ticket), though you may opt to sip coffee or enjoy a civilized afternoon tea instead.