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THE BATHS OF CARACALLA EXPLAINED

View of Baths of Caracalla exterior in the
year 216 AD as seen from above

View of Baths of Caracalla ruins from
above in year 2016

The Baths of Caracalla in 216 AD and 2016 AD
Looking at the South-West side of the Baths
Surrounding gardens & walls built starting in 217 - 222 AD

Welcome to the Baths of Caracalla page, where I explore one of Rome's largest and greatest Imperial baths that served thousands of Romans every day for over 300 years. This vast bathhouse was built by the bad-tempered and murderous Roman emperor of the same name. This vast bathing and entertainment facility covered 100,000 square metres (1,000,000 square feet).

And, believe it or not, this was not the largest Roman baths in the city of Rome - that distinction belongs to the Baths of Diocletian, which is explored on another page. Nevertheless, the Baths of Caracalla are worthwhile visiting simply because so much of the huge and sprawling structure still exists, which really helps you to understand the vast scale and grandeur of an Imperial Roman Baths.

To jump to a specific topic, please use guide below or keep scrolling and explore.

photo of what the Baths of Caracalla ruins look like today as seen from above

image recreation of what the Baths of Caracalla looked like in the 3rd century

The Baths of Caracalla in 235 AD and in 2020 AD
Looking at the North-East side of the Baths

The image above shows a view of the full Baths of Caracalla complex from the other side and includes all the surrounding gardens, walls and other buildings, which were completed five years after it opened. The main building also took five years to build, from 211 to 216 AD, for a total of 10 years.

The alternating images show the ruins today, followed by a reconstructed view of what the baths looked like 1,800 years ago. In the 21st century, the surrounding walls and structures are mostly gone, with just traces here and there of what once existed. Fortunately, most of the main baths' brick and concrete infrastructure is still standing, thus making them the most complete large Roman baths today despite the apparent degradation.

The whole complex, comprised of the main building, surrounding walls, and libraries (top left and right), occupied 25 hectares (60 acres). Its location in Rome was 1.2 km (3/4 mile) due south of the Colosseum, as seen on this map. The main building contained 13 bathing pools (4 cold water, 7 hot water, 2 warm water) and one giant outside swimming pool.

These baths were in operation for 321 years, from 216 to 537 AD. In its final year, during the Gothic War (535-554 AD) between the Ostrogoths and the Eastern Roman Empire, the Ostrogoth barbarian leader Witigis destroyed many aqueducts supplying Rome with vast amount of water, effectively shutting down most of Rome's baths.

THE NAME AND HISTORY EXPLAINED

The building gets its name from Emperor Caracalla (below, right), who reigned (211 - 217 AD) during its construction only to die at the young age of 29 when he was assassinated just one year after the baths opened in 216 AD.

It was his father, Emperor Septimius Severus (below, left), who commissioned the construction of these baths in 211 AD, the same year of his own death by illness in Eboracum (York), England. Interestingly, Caracalla co-ruled with his father for three years, beginning in 198 AD until his father died in 211 AD.

Caracalla's father began the construction		Caracalla completed the baths and co-ruled with his father for 3 years
Caracalla image courtesy of M. Barrot CC BY-NC-ND 2.0

The official Roman Latin name for the Baths of Caracalla was the Thermae Antoninianae or Antonine Baths in English - because Emperor Caracalla's last name was Antoninus. His full name when he became Emperor in 196 AD was "Marcus Aurelius Severus ANTONINUS Augustus", with the "Augustus" being a title only. Nearly all Roman Emperors added the title Caesar or Augustus to their names.

Despite Caracalla's reputation as an evil Emperor - hot-tempered and treacherous (he had many people murdered, including his brother and wife) - the vast and luxurious bathhouse completed under his reign still stands as a testimony to the greatness and splendour of Roman architecture.

Unfortunately, much of the structure was destroyed in the earthquake of 847 AD, which also damaged many other buildings in Rome. Despite the severe damage, the extensive ruins are still impressive and attract millions of visitors every year. Each summer, the ruins are used as a backdrop for musical concerts and operas.

CONSTRUCTION OF THE BATHS

The main baths structure took 9,000 workers five years to build between the years 211 to 216 AD. However, before the baths could be built, over 10,000 Caledonian prisoners from present-day Scotland first had to clear the land. And then, after the Baths of Caracalla were completed in 216 AD, the surrounding outside structures - the pleasure gardens, walls and other formations - were built from 217 to 222 AD by Emperors Heliogabalus and Severus Alexander.

Below is an image of the interior of the Baths of Caracalla when it was new and pristine in the third century AD:

photo of what the Baths of Caracalla Great Hall ruins look like in the year 2018 AD

Baths of Caracalla Great Hall and Frigidarium in 300 AD highlighting the high ceiling and columns and marble floors

Main Hall between Frigidarium and Tepidarium Pools. Shown how it looked in 216 AD and then in 2018 AD

In the image above, the Great Hall between the Tepidarium and Frigidarium is shown with its huge gray granite columns from Egypt. There were eight of these enormous columns in the Great Hall and they supported a high, vaulted ceiling above.

Notice also how the walls and floors are covered with a lavish amount of white and coloured marble, which combined with the many statues and large glass windows, created a place of splendour, light, and beautiful architecture. If this hall, with its high ceilings and windows, reminds you of the inside of a Medieval Gothic cathedral, that is because the Romans developed the architecture which future architects used and built upon many centuries later.

The image above is based on an old drawing I remastered to provide better detail, lighting and clarity by recreating all the columns, windows, floors, people and other surface textures. The original artist is unknown to me, unfortunately, but it probably dates from the late 1700s or early 1800s. Though the old image is a bit dark, it nevertheless has a great atmosphere that seems dream-like - and the technical details are excellent.

The main baths area of the Baths of Caracalla encompassed four floors - two above ground and two below. In addition, this huge structure was built to accommodate 6,000 to 8,000 people daily, and 1,600 bathers at any given time. The amount of marble used was about 6500 sq. metres (70,000 sq. feet) and 7 million bricks. This diagram shows the location of the Great Hall in a cross-section of the entire main baths building.

photo of what Baths of Caracalla Great Hall looks like today

image recreation of what Great Hall of Baths of Caracalla looked like in 3rd century

Recreation showing Great Hall marble floors & interior

The construction cost must have been enormous. At over two football fields in size, these baths were huge. It is estimated that, over the six years of its construction, workers had to install 2,000 tons of bricks and concrete each day.

So many bricks were used because much of the infrastructure of these baths were made of brick and concrete. Furthermore, the marble that once covered much of the inside was just a veneer covering that has long vanished - this is explored in the next section.

Out of 250 columns, about two dozen have survived and have been repurposed for use in a basilica and in a public square, which I explore further on. Judging by holes in some of the upper walls, some parts of these baths had extensive wooden balconies for spectators to watch people bathing and exercising below.

BRICKS AND CONCRETE COVERED WITH MARBLE

Like the Baths of Caracalla, many large Roman buildings had a core infrastructure made of bricks and concrete. This method of building began in the third century BC/BCE when Roman architects developed concrete and, during the reign of Emperor Augustus (31 BC - 14 AD), they also started using fired bricks instead of dried mud bricks. With these new durable materials, Roman architects made the infrastructure of public buildings out of brick and concrete because they were relatively easy to make, transport, and use in the building process.

Furthermore, when we look at Roman ruins such as the massive Basilica of Maxentius in Rome (shown below) or any large Roman bath, these buildings have lost most of their splendour. Instead, all we see today are walls made of brick and ceilings made of concrete. Sometimes, even the walls themselves were made of concrete covered with a layer of bricks on both sides, and then a layer of marble or stucco over the bricks was added to make the walls look nice.

Basilica of Maxtentius closeup photo of brick wall and concrete ceiling structure

Brick walls and concrete ceilings of the Basilica of Maxentius

Of course, during Roman times, the walls and floors of these buildings were richly decorated with many kinds of colourful and shining marble. However, because marble was expensive and often had to be transported from far away, it was cut into thin panels (marble veneers), which were then affixed to the walls with iron clamps.

This is why holes are often seen in the walls of Roman buildings where the clamps were attached. These clamps have all been removed by centuries of pillaging, which also has stripped nearly all ancient Roman buildings of their precious marbles, columns, bronze, and artwork.

Because of the high expense, only the inside walls of Roman buildings were covered with marble panels. The outside wall surfaces of Roman buildings typically were covered with a whitish stucco that imitated marble, and there might be a limited amount of actual marble decoration along the top of the wall, for example. However, for temples and other very significant buildings, parts of the outside brick surfaces also were covered with marble sections, as seen in the portico of the Pantheon.

The image below shows a photo of a Baths of Caracalla wall section in 2019, which then fades into a recreated image showing what that same part of the baths looked like 1,800 years ago in 219 AD, a few years after the baths opened. The contrast is quite striking, and it really shows the beautiful effect marble veneers and decorations can have in architecture.

photo of
Baths of Caracalla wall showing wall and dome made of marble, bricks, and concrete

image recreation of Baths of Caracalla wall section showing the various inlaid marbles, pilasters, and entablature

Baths of Caracalla wall section in 2019 AD & 219 AD

As can be seen above, all that remains today are brick walls and parts of a concrete ceiling. The sparkling marble panels, pilasters and decorations that once covered all those surfaces are magically restored in the next image. The Romans loved splendour and decoration - they also liked to show how their vast and powerful empire could furnish them with all kinds of exotic marbles and other materials used to construct their important public buildings.

In addition to brick, these baths were also constructed with large amounts of tuff stone quarried from the hills of Rome and thus easily accessible. Most of the marble content of the baths was in the form of marble panelling and tiles that covered the walls and floors. Also, while some of the estimated 250 columns were marble, most were made of granite, some standing 12 metres (40 feet) high, such as the eight enormous columns in the Great Hall.

The quote below perfectly expresses the pleasant and appealing interior of the Baths of Caracalla before its decline in the 6th century.

The baths were a luxurious place to spend the afternoon. They were lavishly decorated, the walls, floors and ceilings covered in beautiful colored marble, mirrors and mosaics accented with bronze or silver faucets.

The hot air circulating throughout the walls from the hypocaust would have made the walls pleasantly warm to the touch and the air was probably warm and well circulated.

High ceilings and large windows would have given the baths a light and spacious feel.

"Baths & Bathing as an Ancient Roman", Sept. 2004, KJW2

In the next section, I will show how the Baths of Caracalla interior looked in the past versus how it looks today - quite a difference, to be sure - time is not kind to 1,800-year-old buildings.

THE BATHS OF CARACALLA INTERIOR
- THEN AND NOW -

Recreation drawing of Baths of Caracalla Great Hall as it looked when new in 216 AD showing Roman people strolling inside

photo of the Baths of Caracalla Great Hall as it looks in the year 2015 AD

Great Hall side view in 217 AD and 2017 AD

After comparing the two images above, I am sure you will agree there has been tremendous degradation over 18 centuries. All those huge columns, beautiful marble floors and walls, including the windows, statues, and vaulted ceilings ... are all gone. All that remains, just like the Colosseum, is a brick and concrete core stripped of all decoration. My drawing above of the Great Hall is a remaster of an old image I found.

WHAT CAUSED ALL THE DAMAGE?

This was the result of weather, neglect, and earthquakes over a period of almost 1,500 years since these baths closed in the year 537 AD when barbarians destroyed the water supply. Especially damaging was the powerful earthquake of 847 AD that made the Baths of Caracalla's ceilings collapse. Combined with centuries of pillaging, the result is what we see today - a shell of what once was. So many ancient Roman buildings were used as stone quarries and a source for metals. The materials taken were marble, basalt, tuff stone, and metals such as bronze and iron.

Just think how much a neighbourhood can change in twenty or thirty years and then multiply that much time by 75. It is probably amazing that anything remains at all, which makes it all the more remarkable when ancient Roman buildings, such as the Pantheon, have survived almost intact.

MOSAIC FLOORS OF THE BATHS OF CARACALLA

Despite hundreds of years of pillaging that removed virtually all the baths' inlaid marble floors, marble wall panels, and other decorations, sections of the mosaic floors have survived.

These beautiful mosaic floors are quite impressive , and they provide a glimpse of the splendour and colours of these baths. The patterns formed by the little tiles of these mosaics range from two-tone abstract patterns, colourful abstract patterns, and images of sea creatures and Roman athletes. I have included several examples of the various mosaic floor types found in the Baths of Caracalla in the photos below.

ABSTRACT MOSAIC DESIGNS

The image below shows a great example of the abstract floor mosaics found in parts of the complex. These are black and white mosaics, forming a kind of wave pattern. In one of the photos, they have made a wooden walkway to protect the mosaics as people walk through the area.

photo of extensive baths of caracalla mosaics

The large extent of mosaic floors is impressive

In addition to black and white mosaics, the Romans also made floor mosaics that are more colourful and vibrant, as shown in the photo below. These white, green, blue and red mosaics must have delighted many thousands of eyes over the centuries:

photo of Baths of Caracalla floor mosaic that is a
wave pattern made of green, white, red and peach coloured tiles

Colourful mosaic floor patterns of the Baths of Caracalla

In the next photo, we see more mosaics in the foreground with a large, tall staircase in the background that led to the upper parts of the baths. These ancient stairs are covered with plant growth, and the mosaic tiles just below the stairs are also covered with a green moss. Notice how the moss-covered tiles form a very different pattern from the mosaic tiles in the foreground. I can imagine that staircase when these baths were young and filled with people running up and down the stairs. It is amazing and also sad what time does to things and people.

photo of Baths of Caracalla staircase to the
upper part of the Baths with mosaic floor patterns in the foreground

Mosaic floor tiles before a grand staircase to the upper Baths
Image licensed from Shutterstock

The height of the staircase tells us again how large this facility was. It really must have been marvellous when it was pristine and new. I wonder what kinds of rooms or facilities these stairs led to. I cannot imagine there were pools up there, but perhaps there were lounges, lecture rooms, rooms for people to assemble or perhaps lodgings for the employees and slaves that maintained the facility.

photo of Baths of Caracalla floor mosaics
sections from the upper floor which collapsed

Surviving floor mosaics from the collapsed second floor
Image licensed from Shutterstock

The second floor of the Baths of Caracalla collapsed a very long time ago; however, some sections of the floor mosaics have survived, which are shown in the photograph above. I am guessing that the upper floor collapsed during the great earthquake of 847 AD, which caused great damage to this bathing facility and many other buildings in Rome. This earthquake affected a wide part of central and southern Italy, between Latium, Campania and Molise.

Although (these Baths) were stripped of their sculptures and other treasures at an early date, there are still large fragments of mosaics, some of them corresponding to the top floor of the building, which collapsed.

Wikiarquitectura, Baths of Caracalla

In the next section, I will look at some of the more interesting mosaics of mythological figures, athletes, and floral themes.

FLORAL AND FANTASY MOSAIC DESIGNS

Not all the mosaics of the Baths of Caracalla were abstract patterns. There are also images of people and vegetation made from thousands of little mosaic tiles. The three photos below show us an image of spiral vegetation in the centre and an image of a human figure on either side. I am guessing these figures are based on maritime themes of people fighting or controlling monsters of the sea.

two photos of floor mosaics from Baths of Caracalla
featuring wrestlers and a floral swirl design

Mosaics featuring a floral design and two figures

ROMAN ATHLETE MOSAIC DESIGNS

The detailed mosaics below were found on the floors of the Palaestrae exercise courtyards and in the libraries within the exterior exedra sections along the walls surrounding the bathing complex and gardens. These images truly are mosaics made from thousands of small tiles of different colours as shown in this close-up image.

Several muscular athletes have their hair tied up in a cirrus behind their heads with the hair projecting upwards (Cirri in certice), which was typical for male athletes of that period. One of the athletes below has both arms wrapped up in a cloth cesti protecting his arm.

Mosaic floor patterns featuring athletes & referees

On the left and right sides of the image above are referees wearing a toga and holding something that looks like a plant frond. One of the athletes, possibly a discus thrower, is wearing a laurel leaf crown and holding things in his hands. I am not sure what these plants represent - possibly they were athletic awards of some kind.

SURVIVING SCULPTURES FROM THE BATHS OF CARACALLA

In addition to the marble and mosaics on the walls and floors, many bronze and marble sculptures were placed along floor surfaces and in numerous wall niches. A painting (shown below) by Spanish painter Virgilio Mattoni de la Fuente in 1881 shows us a beautiful vision of what the interior of these Baths may have looked like, filled with so many sculptures. Notice the height of the sculptures in the painting - they were often quite large.

Baths of Caracalla hallways filled with
large sculptures is shown in a painting from 1881

"The Baths of Caracalla" by Virgilio Mattoni de la Fuente, showing many large statues - 1881

Usually based on mythology, some of those sculptures have miraculously survived and show us how splendid these baths must have been. They were primarily located in the Frigidarium area of the Baths, as shown in the section below. Typically, the Frigidarium and Caldarium pool areas were the most ornate, filled with statues and much shining marble. As mentioned earlier, these statues were often quite large. For example, the statue below was 3.7 metres high (12 feet), and the next statue of Hercules was 3 metres high (10 feet).

photo of 'The Farnese Bull' statue from Baths of Caracalla

Farnese Bull statue - excavated in 1546

photo of hercules statue and asclepius statue
that were in the baths of caracalla

Statue of Hercules (left) - Statue of Asclepius (right)

Based on floor locations and niches in the walls, it is estimated there were approximately 120 marble and bronze statues inside the Baths of Caracalla complex. The amount of work and artistry the Romans lavished upon their Imperial Baths was astonishing. It is amazing any of the statues have survived, especially the huge "Farnese Bull" shown above, for example.

The reason why some of these statues bear the name "Farnese" is that it was the family name of Pope Paul III (1534 - 1549) (Alessandro Farnese), who acquired the Baths of Caracalla statues. This Pope acquired many ancient Roman statues. If you see images of the statues of Harmodius and Aristogeiton that are said to be from the Baths of Caracalla, be advised that they are not - these magnificent statues were discovered in the ruins of Hadrian's Villa in Tivoli outside Rome.

The next photo below shows one of the giant tubs (basin) made of gray granite from Egypt. It is from the Baths of Caracalla and it is now located in the Gardens of Boboli. Notice the lady standing beside the granite tub - you can see how huge it is. A common feature of these huge Roman stone tubs is how they are decorated with rings and a Gorgoneion.

photo of granite tub from Baths of Caracalla
that is now located in the Gardens of Boboli

Granite tub from the Baths of Caracalla moved to the Gardens of Boboli in Florence
Image courtesy of Mitko_Denev

Other basins from the baths have survived - click this link to see another Baths of Caracalla stone tub in the Piazza Farnese being used as a fountain. It is interesting to think that patrons of the baths also used these huge tubs for bathing and recreation. Perhaps these tubs were used in the Caldarium, and hot water filled the interior. If this tub was not sunken below the floor, I imagine a small staircase or ladder was required to enter it.

THE NATATIO OF THE BATHS OF CARACALLA

Like all large Thermae bathing facilities, the Baths of Caracalla had a Natatio swimming pool just outside the main building. This enormous pool is 50 metres long (165 feet), 22 metres wide (72 feet), and 1 metre (3 feet) deep. The walls surrounding the pool were over 20 metres high (65 feet). Below are four photos of this Natatio, taken from different angles in 2019.

photo of natatio pool in baths of caracalla with emphasis on wall that held numerous statues in wall niches

Natatio pool back wall that held statues
By permission of Socorro66

The first photo above focuses on the walls surrounding the pool. The high wall on the left has many recessed niche spaces that once held many beautiful statues. You can also see long vertical spaces, lightly coloured, where large columns once stood. The next photo focuses on the actual large pool that was the Natatio.

Natatio pool back wall
Image courtesy of Kanesue - CC BY-2.0

This shot conveys the enormous size of the pool and the heavy presence of the wall containing recessed niches. It looks like grass now mainly covers the floor of the pool. The heavy walls have a brick and concrete core that used to be covered with marble veneers and much decoration. Those objects you see in the pool are lights that illuminate the walls after sunset. On close examination, this pool is not as deep as one might think - only 1 metre (3.25 feet). For the average person today, the water would reach only your waist. However, because Romans were shorter than us, averaging 166 cm (5.4 feet) in height, the pool was deeper for them, especially for the young.

photo of plunge pool in frigidarium of baths of caracalla and looking towards the natatio pool and the wall that held
numerous statues in wall niches

Plunge pool between Frigidarium & Natatio
By permission of Socorro66

The third photo of the Natatio area above is a nice shot of a nearby "plunge pool." This plunge pool is located between the Natatio and Frigidarium areas of the baths, as seen in this diagram (click to view). The photographer is looking beyond the round pool and into the Natatio pool area, where we can once again see the wall that once housed many statues.

Between the statues in the wall niches, three massive columns once stood along the wall, interspaced with smaller columns. These columns are shown below in two alternating images that form my "then and now" recreation. Another photo, further down in the next section, shows one of these three massive Natatio columns now standing in a public square in Florence, Italy.

Natatio Pool wall in 2015 versus 216 AD
2015 Photo (modified) courtesy of Steve Knight

Though this pool was as large as an Olympic-sized pool, it was only half as deep and not designed for serious swimming. I like to imagine this pool on a hot summer day when it was filled with hundreds of happy people splashing and having great fun. Looking at how the pool looks today, it can be hard to imagine this pool sparkling and alive with so many people. Nevertheless, for a few centuries, this pool undoubtedly was a bustling and popular place that gave much enjoyment to countless people.

BATHS OF CARACALLA COLUMNS THAT SURVIVED

photo of column taken from baths of caracalla which is now located in the 'piazza di santa trinita' in Florence, Italy

A granite column from the Baths of Caracalla Natatio
Piazza di Santa Trinita in Florence, Italy

As mentioned earlier, a massive column from the Baths of Caracalla Natatio pool has survived, which is seen in the photo above. This column was taken from the baths in 1562 and given by Pope Pius IV to the powerful Medici family in Florence, Italy, where it now stands in the Piazza di Santa Trinita.

Lady Justice stands proudly in the middle of Piazza Santa Trinita, on top of the tallest ancient Roman column in Florence. The 11.17 meter high oriental granite column weighing about 50 tons originally came from the Natatio, the monumental swimming pool of the Baths of Caracalla in Rome.

The Florentine, April 7, 2011

As described in the quote above, this ancient and massive column, made from gray granite, stands 11 metres high (37 feet), weighs 50 tons, and it took a year to transport from Rome to Florence. The column was placed in 1565, and a reddish/purple statue - made of rare and very hard porphyry stone - was positioned on top in 1580. It looks like they added a Doric capital, which originally was Corinthian.

photo of 22 granite columns
taken from the Baths of Caracalla which are now inside the basilia of Santa Maria in Trastevere

22 Baths of Caracalla columns in the Basilica of Santa Maria in Trastevere, Rome
Photo licensed from JeffBondono.com

In addition to the massive column now in Florence, 22 other smaller columns from the Baths of Caracalla have survived, as seen in the photo above of the Basilica of Santa Maria Trastevere interior in Rome. This photo conveys well the weight and size of these columns, in addition to their wonderful sheen that has survived the centuries.

Most of these columns also are made of gray Egyptian granite - but not all. You will notice that some of the columns are beige instead. And not all capitals on the top of the columns are alike - most are Ionic, but some are Corinthian. These capitals came from a Roman temple devoted to Isis, an Egyptian goddess. When the shocked Church officials realized this, they had all the Isis images quickly chipped away from these capitals.

Interestingly, other parts of the Baths of Caracalla were also used to construct this same church, as shown in a photo below of the church's entrance area. The lintels on the sides of the church's entrance, and the decorative panels along the bottom of the wall, were all taken from the Baths of Caracalla. The church we see today was constructed in the 1140s AD by Pope Julius II. However, it was built upon a foundation from a previous church.

photo of marble
lintel and panels from Baths of Caracalla being used in the entrance of the Basilica of Santa Maria Trasteveree

Marble lintel and panels from Baths of Caracalla used in entrance to Basilica of Santa Maria Trastevere
Photo licensed from Shutterstock

This church is just one example of how the Baths of Caracalla's marble decorations were stripped and repurposed over the centuries. The amount of marble that covered the walls and floors of these enormous baths must have been considerable - and it has all vanished. Some of the marble was burnt to make lime powder for mortar, but much of it was used in constructing newer buildings, especially during the Renaissance period and beyond.

THE WORLD BENEATH THE BATHS OF CARACALLA

In the past, like today, most visitors to the Baths of Caracalla are unaware of an extensive system of underground tunnels under the enormous baths. These tunnels, 6 metres wide (20 feet), ran for 4 km (2.5 miles) and contained 50 brick furnaces (Praefurnia) attended by hundreds of slaves feeding them wood to heat water for the Caldarium, Tepidarium, and saunas.

Ten tons of wood were required daily by the Baths of Caracalla alone. Ensuring a constant supply of wood for the baths was so important that it became one of the Emperor's responsibilities. Below is a photo of part of the wide underground tunnels that serviced the Baths of Caracalla:

photo of tunnel under the Baths of Caracalla

Section of the 4 kilometres of tunnels below the Baths of Caracalla
Image courtesy of Oscar Ferrari

Below is another photo of the tunnels below the Baths of Caracalla - notice the square hole in the ceiling followed by another opening further back. These openings probably served two purposes. First, they were skylights for the dark tunnels below. Secondly, these openings allowed air circulation that provided fresh air to the slaves as it helped to reduce potential mould or wood rot in the tons of fuel wood stored in the tunnels.

photo of tunnel below Baths of Caracalla showing square opening in ceiling

Tunnel below Baths showing square skylights in ceiling
Image courtesy of Oscar Ferrari

The diagram below shows two of the Baths of Caracalla's 50 brick furnaces in operation as they heat water entering from lead pipes connected to a cistern on the surface. This heated water is for the Caldarium pool above. Also shown is how hot air and smoke from the furnaces were channelled into a space below the pool floor above the furnaces, called the hypocaust, whose purpose was to heat the floor. Typically, the hot air and smoke that circulated throughout the hypocaust existed through vertical passageways in the walls that led outside. The water was heated in boilers made of copper, none of which survived. Today, when walking through the tunnels below the Baths of Caracalla, one will not see any pipes, furnaces, or boilers - they have all vanished with time.

diagram of how furnaces worked with water to heat the Caldarium in the Baths of Caracalla

Diagram of furnaces & water system in tunnels below Baths

The burning of wood in the 50 underground furnaces served two purposes: it heated water inside large copper boilers, while the hot smoke and air heated the floors and walls as it travelled through passageways to the roof. I imagine these rooms, with their heated surfaces, were especially pleasant in winter. Rome does get cold in winter but receives only a light dusting of snow every other year. Temperatures can go down to 0 C (32 F) at night from December to February.

WATER CIRCULATION IN THE BATHS OF CARACALLA

I have explained how vast quantities of water were brought to the Baths of Caracalla, and how it was stored, and how some of the water was heated. However, in this section, I want to focus on the overall circulation of that water - the total flow of water in and also out from the baths.

Roman engineers and architects had to build a system for disposing of used water that was as robust as the systems that delivered it. And they also had to design a system that made much use of that disposed water as it coursed its way through Rome's sewer system.

photo of inside the Cloaca Maxima ancient Roman sewer in Rome today

Inside the Cloaca Maxima Roman sewer today
Thank you to Elisabetta Bianchi - Educational Use

Without a doubt, the Romans built an enormous amount of water storage for the Baths of Caracalla - and for a good reason. This vast bathing facility required a tremendous amount of water every day. For example, just one pool, the Olympic-sized Natatio outside swimming pool, would have required many thousands of litres (gallons) each time it was refilled.

The water demands of this facility were indeed steep. 80,000 cubic metres of water (21 Million US Gallons) were required by this bathhouse daily, delivered by its dedicated Acqua Antoniniana aqueduct at 70 litres per second (18 Gallons). But once this huge amount of water was used - where did it go?

Ancient Roman sewer pipes stacked against a wall
Image licensed from Dreamstime.com

When the pools were drained, all the water leaving the complex was used cleverly so that it ran through nearby latrines before making its way to the main sewer of Rome called the Cloaca Maxima, shown at the start of this section. This sewer was built in the 6th Century BC, and it is still being used.

Below is a diagram showing the flow of water through the Baths of Diocletian - from the aqueduct to the cisterns, and then to the pipes, each pool, and out to the sewers. The diagram also shows the location of the baths within the ancient City of Rome:

diagram showing whole water system of baths of caracalla starting at aqueduct to cistern to pipes to pools and then to the sewers

Baths of Caracalla water system from aqueduct to sewers
Image redeveloped and based on image from The Times

The method of water circulation shown in the diagram above worked well for centuries after the baths opened in the early second century. Every day, enormous amounts of water entered and then exited the bathing complex, greatly assisting the flow of sewage all throught that part of ancient Rome.

Undoubtedly, these huge baths demonstrate the engineering and planning skills of the ancient Romans who built the aqueducts, cisterns, pools, underground tunnels, pipes, furnaces, ventilation, and sewers. These baths were complex structures that operated well for centuries. The organizational skills and architectural prowess of the Romans are still awe-inspiring. Despite their faults, the Romans built a dynamic civilization that accomplished incredible things, some of which survived and inspired much of the Renaissance's art and architecture, for example.

THE MYTH OF THE BRONZE MIRRORS OF THE BATHS OF CARACALLA

Type "Baths of Caracalla bronze mirrors" into a search engine. The search results will list numerous websites saying the outside swimming pool (Natatio) of the Baths of Caracalla indeed had elevated bronze mirrors that redirected sunlight down to make the pool warmer and brighter. The Romans allegedly built these mirrors because the Natatio swimming pool area had 20-metre (65 feet) high walls that cast shadows over the pool most of the day.

the reflecting bronze mirros of the Baths of Caracalla shown as they direct sunlight into the Natatio pool
in the year 220 AD - these mirrors are an unfortunate myth

How the Natatio may have looked with sunlight-reflecting bronze mirrors

Some websites even claim that the pool was "surrounded" by these reflecting mirrors. Others say there was a network of these mirrors suspended above the pool. In the image above, I try to show how these mirrors may have looked high above the outside Natatio swimming pool of the Baths of Caracalla early in the third century.

When it comes to history, there are always legends and myths that - although fascinating - are sadly not true. And because of today's internet and social media, it does not take much for something that is not true to become a fact that spreads like wildfire. In my articles, I try to separate fact from fiction, which is not always easy.

As I researched these bronze mirrors of the Baths of Caracalla, I began to suspect this was a case where there is no actual documented or physical proof that something historical was actually true, despite many websites - mostly repeating each other - saying it is true. Sometimes we all come across information on the internet that is based on a misunderstanding or distortions of fact. The fascinating story of the reflecting bronze mirrors that directed sunlight into the Natatio swimming pool of the Baths of Caracalla is such a case.

This story of these bronze mirrors - truth or fiction - is fascinating but a bit long. If you are interested in reading more on the subject, then please click the following link that takes you to a page I have prepared that discusses the subject of the bronze mirrors in detail:

Why the reflecting bronze mirrors of the Baths of Caracalla are a myth

A LAST LOOK AT THE BATHS OF CARACALLA

To conclude this exploration of the Baths of Caracalla, I would like to provide a farewell look at these magnificent old baths. Below is a great photo showing the impressive height of the ruins, which were even higher before the roof collapsed at 45 metres (130 feet). Today, the walls still stand 37 metres high (122 feet). When you visit these ruins in person, you will be stunned by the size and height as you try to imagine what it was like when theses giant baths were filled with people, and lavishly covered in marble, mosaics, and statues.

photo of Baths of Caracalla looking through Caldarium arch

Looking through the Caldarium and into the Great Hall beyond

The Baths of Caracalla are definitely worthwhile visiting if you are in Rome. Though these were not the largest Baths, it is the best preserved, and the ruins are massive. Also, the grounds that comprised the whole baths complex, though in a ruined state, are all there.

In comparison, whole sections of the Baths of Diocletian complex no longer exist, though what does remain is very impressive. Another good reason to visit is that crowds tend to be far less than at the Colosseum, for example. And you can now also visit the underground tunnels and an area devoted to the Roman god Mithras.

This concludes my look at the Baths of Caracalla - I hope you enjoyed my exploration of this ancient and huge bathing complex.

DID YOU KNOW?

A working Roman Bath still exists and has been used for 2,000 years. It is located in north-eastern Algeria where a Roman city once existed. Its Roman name is The Thermal Baths of Flavius (Aquae Flavianae) and it is now called Hammam Essalihine - "The Bath of the Righteous." This is a thermal bath where the water is really hot - 70 C (150 F) and also mineral rich and beneficial, it is believed, for people with ailments such as arthritis or rheumatism.

2,000 year old Roman thermal "Baths of Flavius" still being used in Algeria

Image courtesy of Abdallah Mosbah