Public bathing complex of ancient Rome, designed for relaxation and social activity as well as bathing. The Romans developed public baths to a high degree of sophistication and standardization. They consisted of a large open garden surrounded by subsidiary club rooms and a main block that contained three large bath chambers hot room, steam room, and warm room and smaller bathrooms, cold room, and courts for exercise. Imperial thermae, such as the Baths of Caracalla (AD 216), were immense and opulently furnished. Service was supplied by slaves moving through underground passageways. Heating was accomplished by circulating heated air from a fire under the floor. Lighting of the enormous rooms was provided by an ingenious system of clerestory windows