Basilica Cistern

The Basilica Cistern is an underground water storage cavity about the size of a football field. It is located under the city of Istanbul, Turkey and was built during the reign of Justinian about 1500 years ago.

 The roof of the cistern and the city above are held up by 336 marble columns which are not all the same.

The head of medusa is carved into the bases of two of the columns.

One is placed sideways and the other upside down.