Basilica Cistern or Yerebatan Sarayı ( Sunken Palace) in Turkish

The Basilica Cistern had been constructed by 1. Iustiniaus in 542 BC to supply water for the surrounding palaces. The locals called it the Sunken Palace because it looked like an undreground Bzyantian Palace.  The cistern was next to a square called Basilica Stoa this commercial building also gave the cistern its name.  Istanbul city was growing rapidly.
 The emperors were bringing water from outskirts of Istanbul.  However in war times these channels were being demolished that was why they had needed these huge cisterns.

In the borders of the old city it was explored over 70 cisterns.  The basilica Cistern is the biggest of all.  The dimensions are 138 x 64.6 meters and the height is 9 meters.  Thişs counts roughly 80000 metric tonnes of storage capacity.  The walls and base of the cistern is 4.8 meters thick brick walls covered by 5 cm insulation concrete.  It have been used 336 columns have been used to carry the ceiling that were placed every 4.80 meters.  These columns and some of the materials have been brought from old or antique buildings.

It has been used for the watering system of Topkapi Palace for a while then has been forgotten.  In 1150 the Dutch travveller P. Gyllius has explored the cistern again.  After 1940 in The Turkish Republic the renovation has started and in 1987 after extracting 50000 metric tones of mud in 2 years the museum started to accept visitors.

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