Rotated medusa heads
The highlight of the cistern visit is the two ancient Medusa heads that were used as column basesone upside down, one rotated on its side. There are competing theories as to why the heads were placed this way, whether it was a deliberate Christian rebuke to the pagans who believed in Medusa, or out of a mere lack of appreciation by the builders as to the significance of the ancient relics who simply needed strong blocks to support the cistern columns.