Baths of Caracalla

Listen for a moment. The traffic of Rome fades here into wind moving through umbrella pines. Gravel crunches underfoot. Ahead of you, walls of thin red brick rise higher than most modern buildings, open to the sky. Swallows dart through gaps where vaults once closed. The air smells of dry grass and warm stone. It is quiet now. But for more than three centuries, this was one of the loudest, steamiest, busiest places in the ancient world.

You are standing in the Baths of Caracalla. The complex opened around 216 CE, under the emperor whose nickname it carries. Work may have started under his father, Septimius Severus, and later rulers added the outer enclosure. Caracalla himself is remembered badly. He had his own brother, Geta, murdered and ordered his name erased from monuments. Yet this gift to the people of Rome outlived his reputation by a very long time.

Try to picture the scale. These were not a private spa. They were public baths, open to ordinary Romans, and ancient sources suggest they could hold around 1,600 bathers at once. The central bathing block sat inside a huge walled park. There were gardens, walkways and exercise yards. Two libraries stood within the enclosure, one for Greek texts and one for Latin. A visit here was a whole afternoon of washing, talking, reading and being seen.

The walls in front of you are brick on the outside, but brick was only the skin. Behind it is Roman concrete, a mix of lime, volcanic ash and rubble poured in layers. This material is the reason so much still stands. Look closely at the wall faces. You will see neat rows of holes. These held wooden scaffolding during construction, and later held marble cladding. Almost all of that marble is gone now.

The bathing followed a sequence, and the rooms followed it too. Bathers moved through changing rooms into the warm room, the tepidarium. Then came the caldarium, the hot room, a round hall under a great dome that collected the afternoon sun through large windows. Finally they cooled off in the frigidarium, the cold hall. Beyond it lay the natatio, an open-air swimming pool. Imagine marble, mosaics and statues on every surface.

Here is something most visitors miss. The real engine of these baths is under your feet. Beneath the floors runs a network of service tunnels, wide enough for carts. Slaves and workers moved through them out of sight, feeding wood into furnaces day and night. Hot air flowed under raised floors and through hollow walls. This system is called a hypocaust, an underfloor heating method. The elegant life above depended on hard, hidden labour below.

All that water had to come from somewhere. A dedicated branch of aqueduct, the Aqua Antoniniana, was built to supply the complex. It drew from the older Aqua Marcia, one of the great water lines feeding ancient Rome. Water filled large cisterns before flowing into the pools and basins. When you look at the ruins, remember that water was the purpose of everything here. The stone was simply the container.

And now a second surprise. Deep in those underground tunnels lies a Mithraeum, a shrine to the god Mithras. His cult was a mystery religion, popular with soldiers, with secret rites held in dark, cave-like rooms. This is the largest Mithraeum yet found in Rome. While crowds splashed above, a small community met below in lamplight. It is a reminder that Roman religion was not only temples and public ceremony.

The baths kept working long after Caracalla's death. Their end came in the sixth century, during the wars between the Goths and the Eastern Roman Empire. In 537, the Gothic army besieging Rome cut the aqueducts. Without water, a bath complex is just an enormous empty building. Over the following centuries, people took the marble, the columns and the metal fittings. Earthquakes brought down parts of the vaults. The ruins slowly became quarry and pasture.

Yet treasures stayed buried. In the sixteenth century, the Farnese family excavated here and found colossal sculptures. Among them were the Farnese Hercules and the Farnese Bull, a dramatic group carved from a single block of marble. Both are now in the National Archaeological Museum in Naples. In the nineteenth century, excavators uncovered floor mosaics showing athletes and trainers, now in the Vatican Museums. So pieces of this place are scattered across Italy.

The ruins also moved writers and artists. The English poet Percy Bysshe Shelley spent time here in 1819, and he wrote that he composed much of his drama Prometheus Unbound among these walls. In his time, trees and flowering plants grew over the high vaults. It is easy to understand why. The broken arches, open sky and silence give the site a mood that a complete building could never have.

Today the baths have a newer life. In summer, the Rome Opera stages open-air performances here, with the ancient walls as a backdrop. In 1990, the famous Three Tenors concert took place in this setting, on the eve of the football World Cup final. Thousands of people still gather here on summer nights. In a way, the place has returned to its first purpose. It is again a place where crowds come to enjoy themselves together.

Before you leave, stand still for one more minute. Look up at the tallest wall and follow it to the sky. Then look down at the floor, where small patches of black and white mosaic still survive. Bare feet once crossed these tiles, wet from the pools. Listen again to the wind in the pines. As you walk back toward the street, notice how the city noise returns, slowly, one layer at a time.