First constructed 1500 years ago under the rule of the Roman emperor Constantine, the chamber remained in operation for a thousand years until the Ottoman era. The largest cistern in all Constantinople with a capacity to hold 80,000 cubic meters of water, the engineering marvel is a rather large facility and still in solid condition.
7000 slaves toiled away for several years to build the waterproof facility. The beads of sweat dropping from their forehead were among the first liquid donations to the cistern, which was designed to hold rainwater for future use.
Many of the marble and granite columns that support the structure were reused from even more ancient ruins or were surplus from other construction projects, so they sport a variety of styles from Ionic to Doric. The two Medusa heads arrived from parts unknown, ending up upside down or sideways to fit into the general architecture without additional modification and also to avoid her direct gaze.