Water supply of the city, due to the lack of potable water within the Byzantine city walls, providing a source for centuries, which are located 25 km to the north of Istanbul. Special danger of poisoning and destruction of water channels that provide the city with water, there was during the war years was very high. To solve this problem in peacetime, the city begins construction of reservoirs.

Water was built by the Emperor Justinian, and delivers water to the underground reservoirs - tanks. The most famous and largest of them - a tank or Yerebatan Yerebatan Sarancisi. It is also called the Basilica cistern, and it dates back to the VI century. Yerebatan Cistern is considered one of the largest, best preserved to our time, the ancient reservoirs. This place is one of the most weird and wonderful in the world and represents a giant underground water storage tank. Is the tank in front of Hagia Sophia - almost in the center of Istanbul.

Builders reservoir enclosed by a wall of refractory bricks. Its thickness is 4 meters and it is covered with a special waterproofing solution. It kept a reserve of drinking water in case of drought or siege. Turks prefer flowing water stand, almost never used for its intended purpose kept in a tank of water reserves, and it only watered gardens of Topkapi Palace.

To build this tank began during the reign of Constantine I in 306-337, GG, and finished in the year 532, during the reign of Emperor Justinian. This was at a time of glory of Eastern Rome, called the Byzantine Empire. Reservoir actively used until the XVI century. It was subsequently abandoned and badly polluted, and only in 1987 purified and restored Yerebatan Cistern was opened to the public as a museum.

Reservoir width is 70 m., And the length - 140 m. It Holds 80,000 cubic meters of water. A large number of columns are arranged at intervals of 4 m. Total of the number is 336 - they represent a forest. Many of the columns once stood in ancient temples and were brought to Constantinople from remote corners. Due to the difference in the origin, columns differ markedly from each other, for example, varieties used for their creation marble surface treatment method, the number of parts.

The functions performed by two founding pillars of marble blocks coated with a relief depicting monsters of ancient legend - zmeevolosoy Medusa, which, according to legend, could gaze turns to stone any mortal. Columns located at the far end of the dungeon. Byzantine architects especially with them, without further ado, one jellyfish tumbled down the side, and the other turned upside down. This deliberate humiliation of the ancient idol, not a strange negligence. Not far from the jellyfish is a marble column with a relief pattern, which is called "Peacock". This column is taken from the ruins of the Forum of Feodosia, where now is located the area of ​​Beyazit. Monuments of Constantinople, in turn, as well as the ruins of antiquity, just turned into piles of building material.

James Bond movie "From Russia with Love" sailed here on the boat, and then a film director Andron Konchalovsky filmed scenes of his film "The Odyssey" (these are the moments when there are all sorts of horrors in the light of the torches reflected in the water). The vaults of this huge cave and the forest of columns with water dripping everywhere, however, and so makes a strong and intimidating without Konchalovsky those who once visited these places. The city found about forty underground tanks, but it is possible that they find another.