Underground at the baths of Caracalla

The underground network of passages beneath the Baths of Caracalla. © Soprintendenza Speciale per i Beni Archeologici di Roma

Of all the archaeological attractions in Rome, the one that stood out for me the most during my very brief visit to the eternal archaeological city in March earlier this year was the Baths of Caracalla. While the Colosseum neither surprised nor disappointed me, I was quite unprepared for the ruins of what were the second largest of the Imperial thermae in Rome; the largest being those of Trajan. But, the Baths of Caracalla are by far the best preserved. Until recently it has only been possible to visit the above ground remains. Following extensive renovations, the network of underground tunnels and all that they contain is now accessible to the public once again.

Despite considerable restoration, the remains of the Baths of Caracalla do not fail to impress – originally over 40 m in height, in places walls are still around 30 m high. Built for Emperor Caracalla between 211 and 216 AD on an artificial platform that covers an area of 100,000 m², the public baths accommodated about 10,000 people at any one time. The water required was voluminous; it is estimated that the cisterns held over 8 million litres of water. This was a big complex, with around 9,000 daily workmen. The baths were in continuous use until at least the sixth century.

Understandably, the tunnels underground are as extensive. Located in these passages is what is thought to be the largest Mithraeum in the Roman Empire. A Mithraeum being a place of worship of the Persian god Mithra, which was usually underground, dark and windowless. Mithraism was one religious cult practiced throughout the Roman empire from around the first to the fourth centuries AD. This Mithraeum was found about one hundred years ago with a well preserved, 2.5 m deep fossa sanguinis, a square pit in which initiates would have been lowered to bathe in the blood of a sacrificed bull.

The Caracalla Mithraeum has just reopened to visitors after a year of restoration work costing €360,000. It will be connected to other passages of the underground network forming a route for visitors to follow under the baths. Further restoration work for this is expected to take a further two years.

The Baths of Caracalla are open to the public everyday from 9 am to 18.30 pm (Mondays closing at 2 pm), except 25 December, 1 January and Easter Sunday. Standard entry is €6, but the site is part of the Roma Pass scheme. There is a great book shop, and an audio guide tour of the site is available.

30 m high walls at the Baths of Caracalla

The impressive ruins of the Baths of Caracalla, in places the originally 40 m walls still stand at over 30 m.

The side of the frigidarium at the Baths of Caracalla

Walking through the frigidarium.

Marble remains on the walls at the Baths of Caracalla

Over 6,000 cubic metres of marble and granite were used on the walls, remains of which can still be seen in places, along with many mosaic floors.