After touring the Hagia Sophia, we walked across the street to the Underground Cisterns. Built in the 6th century by Justinian, it is the largest surviving cistern from the Byzantine times.What I find interesting is that it wasn't really discovered until around 1545. There was 'rumor' that people could access water through the basements of their homes, even fishing from them. Then the cistern, capable of holding 100,000 tons of water, was uncovered. At that point, they began throwing garbage and corpses there (a mental picture I can't seem to shake!) The columns are beautiful, and perhaps the weirdest is this upside down view of Medusa. They're not 100% sure why she is upside down, but perhaps due to superstition and her gaze at them!