The best preserved and most splendid of the Imperial Roman Baths in the city dating back at the time of the reign of Emperor Diocletian. The Baths were begun by Antoninus Caracalla in 212 AD and opened in 217, remaining in use until the VI century, when the invading Goths cut the acqueducts.
The romantic sun-baked ruins are on a vast scale and are an architectural masterpiece and beneath ground level there is an intricate heating system and hydraulic plant. Their remarkably complex design included huge vaulted rooms, domed octagons, exedrae and porticoes. Of the elaborate decoration only a few architectural fragments and some floor mosaics remain.
The main buildings still maintain their romantic atmosphere and are surrounded by a lovely enclosed garden. During the Renaissance a church, a vast cloister and a convent were built around and into the ruins — much of it designed by Michelangelo.
Today the entire complex is part of the Museo Nazionale Romano, and this juxtaposition of Christianity, pagan ancient ruins, and exhibit space make for a compelling museum stop that’s usually quieter than the city’s usual blockbusters. There’s a large collection of inscriptions and other stone carvings from the Roman and pre-Roman periods, alongside statuary.