What’s Underground in Istanbul (Basilica Cistern)

When we walk in Istanbul, we actually walk above the past. It is possible to reach a hidden part of the history of thousands of years if you dig under your feet anywhere. Because the underground is full of Roman and Byzantine artifacts. The Ottomans never built a cistern and had little to none secret underground tunnels. Therefore, Istanbul has an underground background that focuses on Byzantine heritage. The major example of this would be the Basilica Cistern. It is located right next to the great Hagia Sophia and can be accessed ( and also seen in some parts ) from the Sultanahmet Square.

The Basilica Cistern is a massive water reservoir that is nearly 1500 years old. It is filled to the “brim” with secrets wonders. Let’s talk about it;

The Basilica Cistern covers a total area of nearly 100.000 square feet. The cistern, which has a water storage capacity of nearly 100,000 tons, can be reached by descending a stone ladder that has 52 steps. The interior of the building is supported by 336 columns, each 30 feet high and 15 feet apart. Most of these columns, which were added to the structure in 28 rows, including the Medusa Heads, which were the subject of legends, were collected from the structures considered to be old at that time.

Due to this situation that adds variety to the building in terms of architecture, you can easily notice the column heads with Corint and Dor style while visiting the building. The ceiling of the cistern is supported by arches so that it can carry the weight. Horasan Mortar was poured in a very thick way to ensure the waterproofing of its base constructed using bricks and its 15 feet thick walls.

The magnificent cistern, which is 450 feet long and 200 feet wide, is known as the “Basilica Cistern” because of its old religious structure. When talking about the structure that can be considered huge compared to its counterparts, the use of the name “Basilica Palace”, which is derived from its columnar structure, is also quite common.

The History

Built-in 532 by order of the Byzantine Emperor Justinianus, the cistern was used to meet the water needs of the Grand Palace. During the construction process, water was provided to the gigantic structure, where 7,000 slaves were employed, through 2 arches that extend to the Taksim Square from the Belgrad Forests, 11 miles from the city. One of these arches were built by the order Emperor Valens was 3100 feet, the one ordered to be built by the Emperor Justinianus was 350 feet long.

After the city passed under the Ottoman rule in 1453, the cistern continued to be used for a short time in order to meet the water needs of the gardens in Topkapi Palace. However, when the idea that it was contrary to Islamic rules became widespread in the Ottomans, the use of the structure was abandoned. The discovery of the Dutch P. Gyllius, who came to Istanbul between 1544 and 1550 to investigate the Byzantine ruins, caused the building, which was abandoned to its fate after the Ottomans set up their own systems, gained fame among the Westerners.

The cistern, whose reputation gradually increased after the explorer explained the information about the building in his travel book, underwent 2 major renovations during the Ottoman period. As a result of an accident that occurred during construction work in the area between 1955 and 1960, there was a danger of collapse in 8 columns from the northeastern wall of the building. The traces of this event, where the columns are covered with a thick layer of concrete, are still clearly visible.

The cistern, which is the frequent destination of cultural tours, was added to the cleaning and restoration work carried out in 1987 within by the municipality. Since then, the cistern was opened to the public and hosts artistic events as well as tours. These events are comprised of concerts, galleries, readings, etc. If you want to reach further information about these events you can access their website here: https://www.yerebatan.com/en

The Artifacts

The most interesting part of the cistern is the Medusa Heads, which are placed under the two columns in the northwest corner for support.
Despite various studies conducted on the structure of these column heads, it could not be determined from which structure they were brought here. As the popularity of these pillars has increased over time, it was not long before legends based on Greek mythology have been speculated on these heads.

According to the most famous of these legends, Medusa was one of the most beautiful women of ancient times with her jet black eyes and long hair. Medusa, who had loved Zeus’ son, the demigod Perseus, was sentenced to an eternal curse by the jealous Athena. While Medusa’s long hair turned into a snake as was stricken of her beauty by the wrath of Athena, her gaze began to turn the men who dare to look at her into stone. It is believed that Medusa, one of the most famous characters of Greek mythology, was one of the Gorgon monsters, which, according to a legend, had the power to turn the gazers into stone, while the Gorgon paintings and sculptures were used to preserve large structures and private places, and therefore it is thought that the sculptures were placed for this reason.

In this version of the story, it is mentioned that the mythological entity is one of the 3 female monsters in the underworld. Another section that I think you might be interested in during your Basilica Cistern trip is the column decorated with various carvings and reliefs. It was previously believed that this column, with teardrop-shaped patterns on it, represented hundreds of slaves who died during the construction of the building.

At the endpoint of the cistern are “peacock eyes” made of carvings and reliefs and “tear stones”. The tear column, also known as the “Weeping Column”, gives the appearance of crying because of its moisture condensation on it. There is a wishing pool right behind the tear column. You can feel like walking on the water on the sightseeing platform during the cistern’s tour. The colorful fish in the cistern fascinate those who visit. As soon as you enter the cistern, you continue to explore with more confident steps, feeling that you have caught the mystery of history from the first step. When you come to the middle of the stairs after you start walking in the cistern, you must be ready to discover the biggest cistern of Istanbul. The arrangement of the columns creates a fascinating atmosphere thanks to the successful lighting system. The Basilica Cistern, which had witnessed two empires with its historical features and interesting stones and columns, is one of the frequently visited museums today.


The cistern is located in Sultanahmet Square. The most practical method to reach the historical building, which has the Hagia Sophia Museum on the one hand and the Blue Mosque on the other, is to use the tram running between Kabatas and Zeytinburnu. After getting off at Sultan Ahmet Station, you can reach the cistern after a short walk. Other options for those who prefer to use public transportation are Marmaray with the city buses going to Eminonu. If you want to use your own vehicle to go to the most original building of the Historic Peninsula, you can choose from the parking lots around Topkapi Palace or Eminonu.

Opening-Closing Times and Fees

Due to its cultural content, 5 TL is requested from students who want to visit the building, which you can add to the list of places to visit in Istanbul, and 10 TL from adults. Foreign travelers need to pay 20 TL to enter the building. Since it is not affiliated with the Ministry of Culture, the facility is excluded from the scope of Muzekart. The Basilica Cistern Museum is open to visitors 7 days a week. The only exceptional application for visiting the underground structure, which you can visit between 09.00-17.30, is valid for the first day of the holidays. The building opens at 13.00 noon in the first days of Ramadan and Eid holidays.

Other Underground Structures in Istanbul

Given Istanbul’s history, there are many other underground structures beneath its visible sites. The most important ones are;

  • The already covered “Basilica Cistern”
  • Seferikoz Cistern
  • Magnaure Palace Remains
  • Zeyrek Cistern
  • Hagios Minas Church
  • Anemnas Dungeons
  • Theodosius Cistern
  • Philoxenus Cistern

The Seferikoz Cistern; The impressive 11th century Byzantine Cistern is now under Kadir Has University. Seferikoz Cistern, which was used as a tobacco and food warehouse after losing its cistern function, is also a part of the Rezan Has Museum. It is open to visitors but can be photographed only with special permission.

The Magnaure Remains; 2,300 years old Magnaura is known as part of the Grand Palace. It is located under a carpet store in Sultanahmet. High walls surrounded by greenery, ruins passing through a dark passage to visitors.

The Zeyrek Cistern; Dating back to 1105s BC, Zeyrek Cistern is located in the Cibali District of Fatih, Sarachane. Many people are unaware of this historical place, which is the only example of a cistern in Istanbul with three unique facades with water collection galleries above ground and inside.

The Hagios Minas Church; The building in Samatya is thought to be one of the oldest churches in Istanbul. A church serving the Greek Orthodox faith was built on the Byzantine church in 1834. This building, built by architect Konstantin Yolasigmasis, is located on Samatya, Bestekar Hakkı Bey Street.

The Anemas Dungeons; The Anemas Dungeons in Balat are the only underground dungeons of the city. It is also exceptional and creepy, with underground tunnels, labyrinth cisterns, and torture chambers. Anemas Dungeons are part of the Blakhernai Palace complex, also known as Tekfur Palace. In addition to being the only underground dungeon left in Istanbul from the Roman period. It has exceptional features with underground tunnels, labyrinth cisterns, and extremely narrow torture chambers. According to some claims, the tunnels of Anemas Dungeons stretched all the way to Hagia Sophia in Sultanahmet Square. It was even veined beneath all of Constantinople like a spider web. Many historians and archaeologists say that there are underground roads in Istanbul, built both during the Roman and Ottoman eras, although it cannot be fully revealed and proven. Were these roads really so extensive, did Anemas Dungeons stretch 7 times below ground even at that time? It is really hard to know. Even now, it is not very difficult to come across some parts of them during excavatşon for a metro line.

The Theodosius Cistern; It was built between the years 428 and 443, by the order of Eastern Roman Emperor Theodosius the 2nd. It is one of the important buildings built with the Binbirdirek Cistern (4th century) and the Basilica Cistern (the 6th century). Visiting is free. Currently, there is no touristic establishment in the cistern. The cistern, quite well-aerated and has nice lighting. In this way, we are able to enjoy the architectural beauty of the cistern.

The Hours and How to Get There;

The Cistern is open between 10:00 am and 7:00 pm. You can visit the cistern, which is also open on holidays, whenever you want. The entrance fees of the cistern are; for Turkish citizens 10 TL, For Foreign Tourists 20 TL. Transportation is very easy. After arriving in Eminonu with Marmaray, you can come here on foot. If you want to get on the tram, you have to get off at Sultanahmet stop and from there you should walk about 5 minutes in Peykhane Street direction. When you get on the subway, you can get off at Aksaray stop and take the Eminonu Tramline, after reaching Sultanahmet stop, you can reach the cistern by walking for about 5 minutes. It is very easy to reach the cistern on Piyerloti Street in Fatih’s Cemberlitas district.

The Philoxenus Cistern; The cistern, built in the 4th century, according to Byzantine sources, is the second-largest cistern in Istanbul. The cistern, which has 224 columns inside and has a total size of 38.00 square feet, it has served as a workshop since the 16th century after it was dried. It’s also known as the “1001 Pillars Cistern” in Turkey because of its many columns. The columns in the cistern are combined with pyramid-like headers that consist of two bodies and have no engravings on them. However, there are various signs on the columns. It is stated that these signs belong to the workers working at the time the cistern was built. The cistern located to the west of the hippodrome was cleaned and opened to visitors in the past years. The cistern, which is quite easy to navigate and has an interesting beauty, has managed to survive the years from the 4th century to the time of Constantine the Great. 212 of the 224 columns in the cistern have survived to the present day. In the cistern, there are also sections such as cafes and exhibition areas.

How to get there: You can easily go here by using public transportation;

  • To go to the cistern by tram, you can get off at Sultanahmet Tram Stop (about 300 feet), Cemberlitas Tram Stop (about 900 feet) or Gulhane Tram Stop (about 1800 feet).
  • To go to the Cistern by using IETT Buses; you can reach the cistern by getting off at the Cattikapi Bus Stop (about 1800 feet), Beyazit Bus Stop (about 2000 feet), Akbiyik Bus Stop (about 2500 feet).
  • To get to the cistern by train, you can get off at Sirkeci Train Station (about 2500 feet).
  • To get to the cistern using Marmaray, you can get off at Marmaray Sirkeci Station (about half a mile).

Walking on History

As I mentioned at the beginning, Istanbul is a very ancient city, it has been the capital of three major empires; Eastern Roman, Byzantine ( which is a successor to the former ) and Ottoman. The Ottoman Empire did not have the tradition of building underground structures, hence, most of what is found under the city are from Roman and Byzantine periods. The reason for this, especially about the water reservoirs such as cisterns, is that the Turks had and still have the idea that stagnant water is not as good as running water. That’s why during the Ottoman Empire period the water structures that were built have been the arches to transport fresh water to the city. Although nowadays dams are being built in order to meet the water requirements of this city of 15 million, they are still considered better than underground water storage.

Because of this belief, and other religious and cultural ones, the Turks of the Ottoman era preferred to use the cisterns as mostly warehouses or just let them be filled with mud, which would be later cleaned during the Republican times in order to “reclaim the history of the city”. As you can see from the example of the Hagios Minos Church, Turks did not reform the “sacred” buildings, instead, they rebuilt other religious buildings on top or around the old one.

In order to cover all of Istanbul’s underground wonders I would have to write a book about them, unfortunately, this is neither the place nor I’m the expert to do so. Although I’m going to try to spark some interest in you, there are still many places and artifacts to be explored, who knows maybe in the future they will be opened to visitation and then you can re-visit this city and feel like you have been part of the discovery process.

One of the most coveted and subject to local legends are the “corridors” under the Hagia Sophia. These rumors are based on the imagination of the local populace and lack of study of these “corridors”. The historians and the archeologists that have had the chance to study and explore these structures are convinced that these generally were used as the city’s water infrastructure, freshwater canals or sewages. As you may have noticed a pattern until now, most of these underground structures are found under and around the Sultanahmet Square, the square is located near the tip of the Historical Peninsula ( Golden Horn ). The “old” city has been established on this peninsula because it was the most defensible location ( it was only conquered in 1453 by the most technologically advanced Empire in the world at the time, so the ancient kings and empires that located their palaces on the Horn were somewhat right don’t you think? ), they set their palaces within the fortifications that line the shore of the ancient city. Many contemporary stores and buildings are built on top of the old remains, some get discovered only by chance when the store owner or the owner of the land decides to put an addition. Here are some of the “lucky” finds ( most of which are not even names other that academically and more of which are closed to the public because they are on private properties that can only be accessed by academics ) ;

  • The palace remains under a parking lot in Sultanhamet ( some experts believe that these remains if excavated, can lead up to the Magnaure remains under the carpet store )
  • The basement of an old shopping center ( Kafar Han ) which is also an old Byzantine cistern. Limited visitations are possible as the center is still being used up to this day.
  • The remains of The Philoxenus Palace ( 4th and 5th centuries) that run under the Peykhane Street in Cemberlitas. These remains can be accessed through some of the modern buildings on the street. A small room under Servet Han is being used as the boiler room of the building. A part of the baths of the Palace is nowadays under a carpet manufacturer’s shop and is being used as its lunch hall. The remains have been somewhat restored by the owner of the shop.
  • Sultan’s Cistern under Ali Naki Street in Fatih. The cistern has been used by weavers and woodworkers in the past. It has been left in ruins for a long time. It has reopened in 2007 as a wedding venue after 7 years of restoration.
  • The remains of a church under a cafe. Even the academics could not access it at the time, the building is separated by the foundations of the adjacent buildings.
  • The palace remains that were uncovered after a fire in a shopping center. These remains continue under the “Antik Hotel” and are open for visitations. The remains under the hotel are nowadays being used as the hotel’s restaurant. You can check it out through their website here: http://www.antikhotel.com/

To conclude, Istanbul’s underground it as rich as its surface for those who are curious to explore. The cisterns that have been built for both water storage or for simply to level the ground for a future construction establish a major part of the city’s underground richness. When you visit be sure to check out as much as you can but keep your senses keen, as you might never know, maybe you can find some “corridor” that has been lost for centuries.

Savaş Ateş

I'm a software engineer. I love Istanbul. I have been to 10 different countries. Istanbul is in the top 3 cities. I like to play soccer too :)

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