15 Interesting Facts About Cisterns of Istanbul

The cisterns of Istanbul are big water tanks, built mostly by the Byzantines to store rainwater and aqueduct water for the long sieges of the city. Some are covered halls with hundreds of columns, and several can be visited today. The best known is the Basilica Cistern, close to Hagia Sophia.

Facts About the Cisterns of Istanbul

1. In the past, rainwater gathered from the roofs was collected in small cisterns in the basements of houses. Later during Byzantine and Ottoman periods, much larger cisterns were built for water collection.
2. The cisterns, built to meet the city’s water needs, are only among historical artifacts today and they are not used for supplying water anymore. Cisterns of Istanbul are only touristic attractions today, even if there is water in them today.
3. Great importance was given to the construction of cisterns during the Byzantine period. There are completely covered cisterns in Istanbul as well as open cisterns that looked like a large pools.
4. The Byzantines further developed the cistern system and equipped Istanbul with more than 100 cisterns, so that it would not be deprived of water during the frequent sieges since Istanbul’s water mostly came from outside via aquaducts.
5. In cities built by the sea, such as Istanbul, underground drinking water could be salty and cisterns were needed to collect fresh rainwater.
6. The open cistern in Istanbul Karagümrük district is used as a football field today.
7. Cisterns were used in the Ottoman period just like during the Byzantine period.
8. Whether one could plant trees near a neighbor’s cistern was regulated by the law since trees such as figs had roots could penetrate the walls of the cistern and cause water to leak.
9. The Basilica Cistern, the largest cistern in Istanbul, can hold 80,000 cubic meters of water!
10. The number of known cisterns in Istanbul is constantly changing, as a new cisterns are diccovered time to time. It is reported that there are about 70 cisterns, although their exact number is not known today.
11. The construction of the Basilica cistern took 38 years and approximately 7000 slaves were employed in the construction of the cistern.
12. Turks have always preferred flowing water thats why cisterns of Istanbul lost their importance over time.
13. You can make a wish by throwing coins into the waters of Istanbul’s cisterns!
14. The bottom of the cisterns was brick-lined as a precaution against water leaks, and the corners were rounded or reinforced in this way to prevent leaks. In addition, the walls were plastered from the inside with a special kind of mortar to prevent water from leaking out.
15. Thanks to advancements in cannon technology and city’s defense walls losing importance, sieges became inessential which leaded the need for cisterns to disappear.

Which Other Cisterns Can You Visit in Istanbul?

Besides the Basilica Cistern, you can visit the Binbirdirek Cistern and the Theodosius Cistern, both in the old city. Binbirdirek, also called the Cistern of Philoxenos, lies between the Hippodrome and the Forum of Constantine. It is second largest covered cistern in Istanbul, and its roof rests on rows of marble columns, each made of two pieces joined by a marble ring.

The Theodosius Cistern is older than the Basilica Cistern. Emperor Theodosius II had it built in the 5th century to store water brought by aqueduct, and its roof stands on 32 marble columns. In modern times a municipal building stood on top of it, and after that building was torn down in 2010 the cistern was restored and opened to visitors.

Both are within walking distance of Sultanahmet Square. I recommend my guests to visit more than one cistern, because each one looks very different. You can read more about all three in my post on the top 3 amazing cisterns of Istanbul.

Frequently Asked Questions

What does Binbirdirek mean?

Binbirdirek means 1001 columns in Turkish. The cistern has 224 columns in fact, because binbir, or 1001, is only a way of saying a great many.

Why were so many cisterns built in Constantinople?

The city had few springs inside its walls, and an enemy could cut the aqueducts during a siege. Big cisterns kept enough water for the people, the baths and the palaces for months.

Are there open-air cisterns in Istanbul?

Yes. Three huge open cisterns, called as Aetius, Aspar and Mocius, were built between 421 and about 500 AD. Later farmers grew vegetables in them, so the Turkish name Çukurbostan means sunken garden.