Basilica Cistern Info Guide

Located in Sultanahmet, the Basilica Cistern is an underground treasure trove of Byzantine history in Istanbul. Over time, it has stood its ground, showcasing its magical splendor for generations to see.

While there’s nothing religious about it, the Basilica Cistern is simply called that because it’s a cistern built under a basilica.  Aside from its mysterious surroundings this magnificent structure, also has mysteries below ground in the form of Medusa heads, wish pools, and weeping columns.

What is a Cistern?

Basically, it’s a large underground receptacle build to hold liquid, and more specifically a city’s reserve water supply. It is often created to catch rainwater. When scarcity of water resources exists, the cistern reserve supplies water to meet the demands.


The Basilica Cistern was built by Byzantine Emperor Justinian I, the very same emperor who constructed the Hagia Sophia. While it does seem all that complex in design, the construction of the Basilica Cistern took a full 38 years to be completed.

Emperor Justinian was known as one of the most fundamental rulers at that time. He’s said to have made the most majestic impression of the Byzantine Empire. He did not just provide water to the people living near the Basilica Cistern; he also made them more productive by improving the lands.

16th Century

During the conquest of Istanbul, the cistern was untended for a long time. It was then noticed by Pierre Gilles, also known as Petrus Gyllius, a French natural scientist and topographer who explored the Byzantine ruins in the mid-16th century.

During the time he was touring around the Hagia Sophia, Gyllius noticed that the citizens living in the area were getting their water from the wells inside their houses. Some were even fishing from them. With curiosity and a lighted torch, he decided to enter the cistern.

Upon discovering the large underground receptacle, he took measurements and identified the columns supporting the cistern. He talked about his discoveries in his book, The Antiquities of Constantinople, which then made the structure known to the world.


The Basilica Cistern has a length of about 140 meters and a width of about 70 meters. It covers an overall area of 9,800 square meters and has an approximate water storage capacity of 100,000 tons.

Arches fill the ceiling space that connects adjacent columns, while the walls of the cistern are made of bricks that are 4.8 meters thick. The floor is also made of brick but is coated with a layer of Khorasan mortar to make it waterproof.


The cistern has a total of 336 nine-meter high columns and is descended by 52-step stairs that are made of stone. Ninety-eight of the columns are in Corinthian style, while some of them are constructed in Doric style.

There is a 4.8-meter distance between columns that form 12 rows. Each row is lined with 28 columns. Most of these columns were collected from past, older structures. Others are carved from different types of marbles. Most of the columns are cylindrical, however, a few of them are in angular or grooved form.

The eight columns situated in front of the northeastern wall were on the verge of breaking during the construction. Therefore, each of them was covered with a thick concrete layer to prevent it from getting ruined completely. That’s why their original features were lost and altered.

What to See

The most popular attraction in the cistern is the Medusa heads, but the wishing pool tends to bring out more smiles, while the teardrop column always peaks everyone’s curiosity.

The dark corners and knaves along with the magical lighting, however, are what make the arched columns stand out, and make them so photogenic.

Medusa Heads

The Medusa Heads are one of the main features of the Basilica Cistern. They are located at the northwestern corner of the cistern. Each is located under a column. It is unknown from where or how these two Roman masterpiece sculptures were brought into the cistern.

Medusa is one of the three Gorgon sisters in Greek mythology. She was said to be a woman who took pride in her beautiful features. She loved Perseus, is the son of Zeus and Danae, who is one of the greatest heroes in Greek mythology.

However, Athena also liked Perseus, and she was jealous of Medusa. Athena cursed Medusa and turned her hair into snakes. Because of this, Medusa has been represented as a female monster who had snakes for hair. According to the mythology, Medusa can turn the people who care for her into stone. Perseus is said to have later beheaded Medusa and used the latter’s power to fight his enemies.

Reputedly, Gorgona paintings and structures were placed inside large and private buildings that time to protect them. That’s why the Medusa Heads, as a pair of Gorgona structures, were brought to the cistern.

Others say that Medusa was known to stone anyone who catches even a glimpse of her eyes. In fear of this rumor, the two Medusa heads were positioned upside down.

Wish Pool

While viewing the Medusa heads, you might notice a line of people seemingly throwing things into the water. This area is known as the wish pool, where legend says you must first make your wish, then toss a coin, and wait for it to come true.

Weeping Column

The Weeping Column is also known as the Peacock’s Eye. It is also one of the features in the Basilica Cistern that attracts visitor attention. It stands out among the others because of the shapes on its columns that resemble teardrops. Because of this, it is referred to be a column that never stops crying.

This has been connected to the history back when the cistern was built. Over 7000 slaves worked to construct the palace. Hundreds of them died. This column was said to be built in memory of those slaves who died at that time. Reputedly, you may make a wish and throw money into the water found in front of this column.