From Ancient Serdica to the Central Mineral Bath

The mineral spring in the center of Sofia is far older than the city itself. The history of the area around it takes us back thousands of years. Evidence of human settlement in the Sofia Valley dates back to the Neolithic period, and the warm mineral waters became one of the natural factors that shaped the development of the future city.

Later, the Thracian tribe of the Serdi settled here. The ancient name of the city, Serdica, comes from them.

After the region became part of the Roman Empire, Serdica gradually developed into an important ancient city. Mineral water played a special role in its life. The surviving Roman water-capture structure of the spring was built in the second half of the second century AD and remained in use until the 1950s.

Healing baths operated in ancient Serdica, while archaeological finds show the worship of Apollo and Asclepius, deities associated with health and healing.

Mineral water remained important throughout the following centuries. During the Ottoman period, Sofia became known for its baths, and in the seventeenth century the Ottoman traveller Evliya Çelebi described five mineral baths in the city.

After Bulgaria’s Liberation, Sofia became the capital in 1879 and began to modernize rapidly. In 1889, an international competition was held for a new mineral bath and hotel complex. It was won by the Austrian architect Emil von Förster, but the original plan was never fully completed.

In 1904, architects Petko Momchilov and Friedrich Grünanger developed the concept for the complex in the form we recognize today. The Small Bath opened in 1908, while the Large Mineral Bath opened on May 13, 1913. A year later, a hydrotherapy institute was opened in the northern wing.

In 1944, the bombing of Sofia destroyed the Small Bath and severely damaged parts of the Large Bath. After the war, the building was restored and continued to operate until 1986, when it was closed because of deterioration.

Since 2015, the building has housed the Regional History Museum of Sofia.

The function of the building has changed. The city around it has changed as well.

But the mineral spring remains one of the longest threads connecting the different eras of Sofia’s history.

The project “The Voice of Living Water: Youth Media Academy for the Innovative Social Engagement with Sofia’s Thermal Heritage” is implemented with the financial support of Sofia Municipality – Europe Programme 2026 by the Cosmopolis Foundation, in partnership with the Municipal Enterprise “Tourism”.

Composition and Balneological Properties

The water that reaches the fountains beside the Central Mineral Bath travels a long natural route underground.

The Sofia-Centre mineral water deposit is recharged by rainfall that penetrates the rocks of the mountain ranges surrounding the Sofia Valley. Deep underground, the water circulates through a fractured system located more than 750 meters below the surface.

At the deposit, the temperature of the mineral water reaches 48 degrees Celsius. A laboratory-tested sample showed total mineralization of 266 milligrams per liter and a pH of 9.5.

The water is classified as hyperthermal, low-mineralized, hydrocarbonate-sulphate, sodium-rich and siliceous, and it also contains fluoride. Its measured components include sodium, bicarbonates, sulphates and metasilicic acid.

But what does this mean for the human body?

The official balneological assessment identifies possible uses of the water in therapeutic drinking treatments for certain gastrointestinal, liver and biliary, kidney and urinary, and metabolic conditions.

External balneotherapy may also be used for certain conditions affecting the musculoskeletal system, the peripheral nervous system, the skin and others.

This does not mean that mineral water is a universal cure.

Therapeutic drinking has specific indications and contraindications. The quantity, temperature, method of intake and duration should be determined by a medical professional.

So behind what may appear to be a simple stream of water lies a complex natural process involving rainfall, rock formations, great depth, high temperature and a distinctive mineral composition.

The project “The Voice of Living Water: Youth Media Academy for the Innovative Social Engagement with Sofia’s Thermal Heritage” is implemented with the financial support of Sofia Municipality – Europe Programme 2026 by the Cosmopolis Foundation, in partnership with the Municipal Enterprise “Tourism”.

Between Old Beliefs and Historical Testimonies

Sofia’s mineral water has been used for centuries. Naturally, many stories have developed around its unusual properties.

Today, its chemical composition can be tested in a laboratory. But for people living hundreds of years ago, the explanations were very different.

In the sixteenth century, the scholar Matthew the Grammarian described Sofia in the “Life of Saint Nicholas of Sofia.” He mentioned the hot waters near the city and recorded the belief of the time that people suffering from various illnesses could find relief by immersing themselves in them.

This is an important historical testimony to the way mineral water was understood in the sixteenth century — not proof of a medical effect according to modern science.

Even more colorful are the stories of Evliya Çelebi.

In the seventeenth century, the famous Ottoman traveller described five mineral baths in Sofia. He attributed properties to some of the waters that may sound almost unbelievable today.

For one bath, for example, he recorded the belief that it affected men and women differently. Other waters were believed to help with various illnesses.

This is precisely where history and science must be separated.

These stories do not prove that the water truly possessed all the powers attributed to it. What they do show is that Sofia’s mineral springs had already gained a reputation strong enough to attract the attention of foreign travellers centuries ago.

The connection between water and health also left traces in antiquity. Archaeological finds from Serdica reveal the importance of healing deities such as Apollo and Asclepius.

Over time, two different kinds of history accumulated around the spring.

One can be measured — temperature, mineralization and chemical composition.

The other survives in texts, beliefs and stories.

Both are part of the cultural history of Sofia’s mineral water.

The project “The Voice of Living Water: Youth Media Academy for the Innovative Social Engagement with Sofia’s Thermal Heritage” is implemented with the financial support of Sofia Municipality – Europe Programme 2026 by the Cosmopolis Foundation, in partnership with the Municipal Enterprise “Tourism”.

The Central Mineral Bath

Look at the building in front of you.

The Central Mineral Bath is one of the most recognizable architectural symbols of old Sofia, but behind its façade lies a story that unfolded over more than two decades.

It begins in 1889, when an international architectural competition was held for a mineral bath and hotel complex. The winning design was by Austrian architect Emil von Förster. Construction of the hotel began, but in 1893 the project was halted because of a lack of funding.

In 1904, architects Petko Momchilov and Friedrich Grünanger developed the concept for the complex in the form we know today. In 1906, Momchilov was commissioned to prepare the working plans for the large and small baths.

The Small Bath opened in 1908. The Large Bath opened on May 13, 1913.

The architecture of the building is considered one of the notable Bulgarian examples of Neo-Byzantine architecture from the early twentieth century. Its decorative design also clearly reflects the influence of Secession, or Art Nouveau.

Among its most striking features are the colorful façade friezes with floral and geometric motifs. They were created in 1908 by the artist Haralampi Tachev.

Around the main entrance, you can see the figures of Apollo Medicus — Apollo the Healer — and Tyche, the protector of cities. The stone sculptures were created by Georgi Kiselinchev.

The decorative program of the building is therefore not accidental. It brings together the city, the water and the idea of health.

When the Large Bath opened, it included two swimming pools, family baths and Roman-style baths. In 1914, a hydrotherapy institute was opened in the northern wing.

So the Central Mineral Bath is worth looking at not only as a monumental building.

Come a little closer.

Part of its history is hidden in the details.

The project “The Voice of Living Water: Youth Media Academy for the Innovative Social Engagement with Sofia’s Thermal Heritage” is implemented with the financial support of Sofia Municipality – Europe Programme 2026 by the Cosmopolis Foundation, in partnership with the Municipal Enterprise “Tourism”.

Sofia’s Lost Thermal Culture

At the beginning of the twentieth century, going to a public bath meant something very different from what it does today.

Hot running water at home was still far from common, and public baths played an important role in everyday urban life. But they were not simply places where people went to wash.

They were also part of Sofia’s social life.

When the Central Mineral Bath opened in 1913, it quickly became one of the busiest public places in the capital.

The building had two floors and covered around 5,000 square meters. Prices were relatively low, making the bath accessible to people from different social backgrounds.

During the summer months, it was open from five in the morning until eleven at night.

And every day, between 800 and 1,000 people passed through its doors.

Imagine what up to a thousand visitors a day meant in Sofia more than a century ago.

People from different parts of the city and from different social circles met here. The bath was a place for hygiene and balneotherapy, but at the same time it was part of the social rhythm of the capital.

Today, this culture surrounding mineral water is recognized as part of Sofia’s thermal heritage.

The Central Bath itself offered several different facilities. It had two swimming pools, family baths and Roman-style baths. In 1914, a hydrotherapy institute also opened in the northern wing.

The importance of the bath can even be seen in its architecture.

Instead of being designed as a purely functional building, it was given monumental architecture and rich artistic decoration. Architect Ivaylo Zahariev has described historic mineral baths of this kind as “palaces of water” — representative buildings created to bring people together.

Over the course of the twentieth century, however, everyday life began to change.

Bathrooms and hot running water gradually became common in private homes, and the public bath slowly lost the everyday function it once had.

After the Second World War, the Central Mineral Bath continued to operate for several decades, but in 1986 it was closed because of deterioration.

Today, part of the building is home to the Regional History Museum of Sofia.

But when we look back to a time when up to a thousand people a day passed through these doors, it becomes clear that the Central Bath was much more than a place for bathing.

It was part of the everyday life, encounters and social world of old Sofia.

And this relationship between people and mineral water is part of the city’s thermal culture — a heritage Sofia still carries today.

The project “The Voice of Living Water: Youth Media Academy for the Innovative Social Engagement with Sofia’s Thermal Heritage” is implemented with the financial support of Sofia Municipality – Europe Programme 2026 by the Cosmopolis Foundation, in partnership with the Municipal Enterprise “Tourism”.

The Mineral Map Beneath the Capital

If we say “mineral water in Sofia,” the first place that probably comes to mind is where you are standing right now — the Central Mineral Bath.

But beneath Sofia lies a much larger natural resource.

Within Sofia Municipality there are 31 separate mineral water deposits and a total of 75 water sources, including captured natural springs and boreholes.

And they are not concentrated only in the city center.

Mineral water is part of the history of places such as Bankya, Gorna Banya, Knyazhevo, Ovcha Kupel, Pancharevo and Zheleznitsa.

In some cases, it influenced not only bathing and health traditions, but also the development of entire neighborhoods.

One of the most interesting examples is Ovcha Kupel.

An old local tradition connects the appearance of the mineral spring there with the earthquake of 1858. Local people began calling it “The Hot Water” or “The Pool.”

It is important to remember that this is a historical tradition, not a proven geological fact.

The popularity of the mineral water, however, is very real. People began arriving at the spring from the Sofia region and from other parts of the country. Inns and places to stay appeared nearby, and at the beginning of the twentieth century the spring was captured and developed.

Between the 1920s and the early 1930s, an impressive bath complex was built there to a design by architect Georgi Ovcharov. By 1933, a preventive healthcare complex was also operating near the mineral spring and bath.

The bath therefore gradually became more than a place for hygiene and developed into part of a specialized therapeutic complex.

And the water there received another name — “living water.”

Mineral waters also influenced the expansion of Sofia.

During the first half of the twentieth century, the development of transportation and the desire to use the natural resources around Vitosha for recreation encouraged the growth of the capital toward areas such as Knyazhevo, Gorna Banya and Ovcha Kupel.

Here in the city center, however, the water comes from an entirely different underground world.

The Sofia-Centre deposit is recharged by rainfall that penetrates the rocks of the mountain ranges surrounding the Sofia Valley. The mineral water rises from a pressurized fractured system more than 750 meters beneath the surface, and its temperature at the deposit reaches around 48 degrees Celsius.

Mineral water even appears in one of the most important symbols of the capital.

The coat of arms of Sofia includes Apollo Medicus — Apollo the Healer — representing the city’s mineral springs.

So the history of mineral water does not belong to just one fountain or one building.

From the Central Bath to Ovcha Kupel, from Gorna Banya to Bankya, mineral waters have left their mark on architecture, health culture and even the development of entire parts of the capital.

When we walk through Sofia, we rarely stop to think about what lies beneath its streets.

The city we see on the surface has its own invisible map.

A map of mineral water.

The project “The Voice of Living Water: Youth Media Academy for the Innovative Social Engagement with Sofia’s Thermal Heritage” is implemented with the financial support of Sofia Municipality – Europe Programme 2026 by the Cosmopolis Foundation, in partnership with the Municipal Enterprise “Tourism”.

If you stand beside the mineral spring and begin walking through the surrounding streets, within just a few minutes you can pass places of worship belonging to four different religious traditions.

A mosque.

A synagogue.

An Orthodox church.

And a Catholic cathedral.

This is one of the most interesting parts of Sofia’s historic center — the area known today as the Quadrangle of Religious Tolerance.

But if we go back several centuries, we discover that mineral water is also part of the history of this neighborhood.

The most visible connection stands directly opposite the Central Mineral Bath.

The Banya Bashi Mosque was built in the sixteenth century and is traditionally associated with the great Ottoman architect Mimar Sinan. Its name roughly means “by the bath” or “next to the bath.”

And that is no coincidence.

The mosque was built in an area already known for its hot mineral waters and public baths.

In the seventeenth century, the Ottoman traveller Evliya Çelebi visited Sofia and described five mineral baths in the city.

His account is particularly interesting because it reveals the diversity of life around the water. His descriptions mention baths associated with different groups within the population — Muslims, Christians and Jews — as well as a separate women’s bath.

In other words, centuries ago people of different religions, origins and social positions were already moving through the same area surrounding the mineral springs.

But the city continued to change.

Just a few hundred meters from Banya Bashi stands the Sofia Synagogue, opened in 1909. It was designed by Austrian architect Friedrich Grünanger.

And here we find a fascinating connection.

The same Friedrich Grünanger who designed the Sofia Synagogue also worked with Petko Momchilov on the design of the Central Mineral Bath.

Within just a few years, one architect left his mark on two of the most recognizable buildings in this small part of Sofia — one connected with mineral water, the other with the city’s Jewish community.

A short walk away stands the Orthodox Church of Saint Nedelya, and a little farther on is the Catholic Cathedral of Saint Joseph.

Four religious traditions come together within an area that can be crossed on foot in only a few minutes.

It is important, however, not to turn a beautiful story into a historical myth.

There is no evidence that mineral water itself created Sofia’s religious diversity or tolerance.

The connection is different.

For centuries, the same urban space brought together mineral springs, public baths, markets, religious buildings and people from different communities.

The traces of all these layers can still be seen today.

So after you fill your bottle with mineral water, take a look around.

Within only a few minutes of the spring, you can walk through centuries of Sofia’s history and pass places of worship belonging to four different religions.Without ever leaving the city center.

The project “The Voice of Living Water: Youth Media Academy for the Innovative Social Engagement with Sofia’s Thermal Heritage” is implemented with the financial support of Sofia Municipality – Europe Programme 2026 by the Cosmopolis Foundation, in partnership with the Municipal Enterprise “Tourism”.

Mineral water in the center of Sofia has an unusual feature — it is a natural resource that anyone can access directly from a public fountain.

No ticket.

No packaging.

No need to buy it.

But the fact that the water flows freely does not mean that the resource is limitless.

Mineral waters are part of the natural water cycle. At the Sofia-Centre deposit, the process begins with rainfall penetrating the rock layers of the mountain ranges around the Sofia Valley.

The water then travels through the rocks and reaches a deep fractured system more than 750 meters below the surface.

Mineral water is therefore a natural resource that must be managed, monitored and studied.

And this raises an important question:

What do we do with it?

Historically, Sofia used its mineral water mainly for public baths and balneotherapy. Today, the possibilities are much broader — from balneology and spa use to heating and other ways of using the thermal energy of the water.

Making better use of these resources is part of the modern discussion about the future of Sofia’s thermal waters.

But responsible use also begins with something much simpler.

With the way each of us uses the public fountains.

Take only as much water as you will actually use.

Do not leave plastic bottles or other waste behind.

Do not contaminate the fountains or the space around them.

And leave the place as you would like to find it.

These may seem like small actions.

But when thousands of people pass through a public space, small actions add up.

Mineral water is part of Sofia’s natural wealth.

The question is no longer only how we used it in the past.

It is how we will use it in the future.

The project “The Voice of Living Water: Youth Media Academy for the Innovative Social Engagement with Sofia’s Thermal Heritage” is implemented with the financial support of Sofia Municipality – Europe Programme 2026 by the Cosmopolis Foundation, in partnership with the Municipal Enterprise “Tourism”.

The Hidden Symbols of the Central Mineral Bath

Before you continue, stop for a moment and look up.

The Central Mineral Bath is one of those buildings we easily recognize from a distance, but rarely examine closely.

And it is in the details that architects and artists have left part of its story.

Start with the colors.

Across the façade, you can see rich ceramic decoration with floral and geometric motifs. The decorative friezes were created in 1908 by the artist Haralampi Tachev, one of the important names in Bulgarian decorative art from the early twentieth century.

The architecture combines several influences typical of its time, with Neo-Byzantine forms and Secession-style decoration standing out most clearly.

But perhaps the most interesting details are around the main entrance.

There you can find two figures from ancient mythology.

One is Apollo Medicus — Apollo the Healer.

The other is Tyche — the protector of the city and its prosperity.

These figures were not chosen by chance.

One symbolizes health and healing.

The other represents the city itself.

And the building on which they appear brings those two ideas together through mineral water.

The stone sculptural decoration was created by Georgi Kiselinchev, while the colorful ceramic friezes were the work of Haralampi Tachev.

But there is another fascinating detail that takes us much farther back in time.

Among the surviving objects from ancient Serdica is a coin showing a public fountain. Water flows from spouts shaped like lion heads.

This tells us that public water sources were important enough in the ancient city to be represented even on coins.

But an important distinction must be made.

There is not enough evidence to claim that every lion-head fountain we see around Sofia’s mineral waters today is a direct continuation of those ancient examples or the work of a particular famous artist.

The history is interesting enough without adding details we cannot prove.

So look at the building once again.

The domes are the first thing you notice.

But the next time you pass by, you may see something else — the colors, the ornaments, Apollo, Tyche and the small details that transform a public bath into a work of art.

The project “The Voice of Living Water: Youth Media Academy for the Innovative Social Engagement with Sofia’s Thermal Heritage” is implemented with the financial support of Sofia Municipality – Europe Programme 2026 by the Cosmopolis Foundation, in partnership with the Municipal Enterprise “Tourism”.

What did Sofia look like before photographs, cars and wide boulevards?

Centuries ago, the answer came from the people who passed through the city and described what they saw.

And their accounts are especially interesting because they do not show us the same Sofia.

Each traveller sees a different city.

In 1553, the German traveller Hans Dernschwam passed through Sofia.

His first impression was far from enthusiastic.

He described Sofia as a fairly large but unfortified city, without defensive walls, with low one-storey wooden houses, narrow streets and buildings arranged around inner courtyards.

He noted that craftsmen’s shops opened directly onto the streets, while the mountains surrounding the Sofia Valley could be seen in the distance.

Dernschwam also noticed the large number of religious buildings, counting around fifteen mosques or places of worship from afar.

But one of the things the German traveller did not overlook was the public bath.

He went inside, bathed there with his companions and left one of the most detailed early descriptions of a public bath in Ottoman Sofia — from the arrangement of the rooms to the way the building was heated and used.

Around a century later, Sofia looked very different through the eyes of Evliya Çelebi.

The Ottoman traveller described a much livelier city, with mosques, public buildings, places for walking and a well-developed bathing culture.

In his account, Sofia is not simply a stop along the road.

It is an important urban center, and mineral water is one of its recognizable features.

Çelebi described five mineral baths and also recorded various beliefs about the qualities of the water.

Several centuries later, in 1841, the French economist and traveller Jérôme-Adolphe Blanqui arrived in Sofia.

His observations focus much more closely on everyday life.

He described the Sofia plain, the fields around the city, its population, homes, streets, markets, cafés and public fountains.

He met with Sofia’s governor, Osman Bey, and with the local bishop, Meletius.

His account therefore gives us not only a picture of buildings, but also a sense of how Sofia functioned during the first half of the nineteenth century.

Among all these impressions, Blanqui specifically chose to visit Sofia’s famous mineral baths.

He described the large pool, the smaller rooms around it and the light entering through openings in the ceiling.

He measured the water temperature at around 45 degrees Celsius.

Our final traveller arrived at a completely different moment in the city’s history.

At the end of the nineteenth century, the Czech historian Konstantin Jireček came to a Sofia that had only recently become the capital of the restored Bulgarian state.

His first impressions can be almost shocking to someone familiar with the city today.

He saw crooked streets, wooden houses, open oriental-style shops, uneven pavements and a great deal of mud.

But right before his eyes, the city began to change.

In 1880, Jireček wrote about plans to reshape the old city with new, straighter streets — part of the process that would gradually transform Sofia from an Ottoman town into a modern European capital.

Jireček also took note of the mineral bath.

In the early 1880s, he described the large pool as having a diameter of around eight meters, with water at a temperature of at least 40 degrees Celsius.

Through just four travellers, we can see four different Sofias.

Dernschwam sees a city of narrow streets, wooden houses and the silhouettes of religious buildings.

Evliya Çelebi sees a lively Ottoman center with a developed bathing culture.

Blanqui sees a city of markets, cafés, fountains and everyday life.

And Jireček sees Sofia at the very moment when the old city begins to transform into the new capital.

Yet one thread remains present in all these different pictures.

The mineral water.

Now look at Sofia around you.

The city you see today has very little in common with the narrow streets and wooden houses described centuries ago.

But you are standing beside the same mineral springs that once made travellers stop, observe and record their impressions.

Today, you are the next visitor in that long story.

Perhaps you will fill a bottle with mineral water.

Perhaps you will take a photograph of the building in front of you.

And when you continue your walk through Sofia, try to look at the city as a traveller from the past might have done.

Notice the old façades.

The places of worship.

The streets.

The mountain behind them.

And the water that still rises here, in the very center of the capital.

Because Sofia is not simply a city to look at.

It is a city to discover, layer by layer.

And now it is your turn to discover your own Sofia.

The project “The Voice of Living Water: Youth Media Academy for the Innovative Social Engagement with Sofia’s Thermal Heritage” is implemented with the financial support of Sofia Municipality – Europe Programme 2026 by the Cosmopolis Foundation, in partnership with the Municipal Enterprise “Tourism”.