Underground Istanbul takes you to the 6th century where you can walk along the cistern that was the water source for the city up until water systems were installed in the 15th century. With no natural light coming in, electric lights cast a fire hue on the columns and water. The photo below is what the eye sees.
And then with an adjustement of the camera, the columns are revealed complete with their base in the water.
Various engraving decorate some of the columns.
Two Medusa heads are in the far side of the cistern and serve as the base for columns. This Medusa was set on side, as if lying down or in death with her head cut off.
The second Medusa holds the column as part of her neck. The origin of the Medusas is unknown and the reason for their placement lost but well worth the walk to the end of the cistern. Basilica Cistern was 10 TL and our wait was 10 minutes. April seems to be a good time to sightsee Istanbul (if you can handle 1 sunny day a week.)