On our way back from the Suleymaniye Mosque, we popped in to see the Basilica Cistern, just across from the Hagia Sophia. This subterranean cistern was built in the 6th century by Justinian, using the castoff architectural elements of the Roman Empire. It is the largest of the underground cisterns from this period at about 450 feet long by 200 feet wide, and able to hold about 2.8 million cubic feet of water. The arches that form the ceiling are held up by 336 marble columns, mostly Corinthian in style, in 12 rows of 28 columns. Each is about 30 feet high, and spaced about 16 feet apart. The ceiling and surrounding walls are made of firebrick with a special water-resistant mortar.
The cistern gets its name because it was built on the site of the Stoa Basilica, which was originally built in the 3rd and 4th centuries. It had been forgotten for centuries before it was rediscovered in the mid-16th century by a Dutch scholar who apparently heard stories of his neighbors retrieving water, and even fish, from it through their basements. It was finally renovated and opened to the public in 1987.
Perhaps the most famous features in the cistern are the two Medusa heads, which are used as column supports in the far back corner. For unknown reasons, one is upside down, and one on its side. My favorite detail, however, was the ‘Hen’s Eye’ column, which is carved all over with graceful teardrop shapes. It is said to represent the slaves who lost their lives during the construction of the cistern.