Baths of Caracalla
The emperor Caracalla’s baths could take more than a thousand bathers at a time. The ruins are still enormous: brick walls that once carried vaults over hot, warm and cold halls. The plan, with large rooms in a symmetrical sequence, became a model much later.
The baths were built in AD 212–216, during Caracalla’s reign, south of the city centre. The complex was supplied with water by its own branch of the Aqua Marcia aqueduct. The building stood on a high platform, beneath which ran tunnels for staff, firewood and water. The walls have a concrete core and brick facing and were originally covered with marble, stucco and mosaic. The whole precinct, with gardens, libraries and shops around the baths, was about 300 metres square.
The main building was arranged along a strict symmetrical axis. From the cold bath, the frigidarium, bathers went into a warmer room, the tepidarium, and on to the round hot bath, the caldarium, which was about 35 metres in diameter and covered by a dome. The rooms were heated by hot air from furnaces flowing through cavities under the floors and in the walls. On either side lay a palaestra, a courtyard for exercise and games. The great open-air pool, the natatio, had walls with niches for statues. Many of the famous ancient sculptures in the Naples Archaeological Museum, among them the Farnese Hercules, were found here in the 16th century.
The baths were in use until the 6th century, when the Goths cut the aqueducts. After that the complex decayed and was used as a quarry. The ruins inspired later architects, and the plan with its sequence of large vaulted rooms became a model for, among other things, the great waiting room of Pennsylvania Station in New York, built in 1910. Since 1937 the old caldarium has been used as a summer stage for opera. The ruins show clearly how Roman concrete and brick made it possible to build large rooms without internal supports.