The Yira Bataan Water Reservoir, located in the Eminonu area near the Hagia Sophia Mosque in the European section of Istanbul, was created by Emperor Iostinianos I in the 6th century.
The reservoir, built to provide the city's water needs, is 138m long and 64.6m wide. The reservoir has 336 marble columns supporting strong beams and bridges. The ceiling of the tank consists of arches placed without the use of molds. The walls of the tank, which is 3.5 m thick, have been tipped with special material to prevent the leakage of water.
The reservoir, which is located in a crowded area, was once a stone-paved square and as a result of the spread of its buildings from the Byzantine era to the Ottoman era. Over time, this arena has been subjected to a lot of vandalism. The residents of the buildings broke the roof of the ceiling to draw water from the reservoir.
In 1940, the municipality acquired the houses built above it and built a building on the entrance to the area. Between 1985 and 1988, a large-scale cleaning of the tank was carried out, in which tons of mud were removed and the Siran area was built on it. After this cleaning, the short columns in the southwestern section were raised with pieces of an ancient marble artifact dating back to the early ages.
This artifact, which was used, dates back to the ancient times called the Medusa and Jurgen Ages, and it is not specifically known why it is located in this region.