The Yerebatan Sarayı is the largest of several hundred ancient cisterns that lie beneath İstanbul The cistern was built in the 6th century during the reign of Byzantine Emperor Justinian I.
The cathedral-size cistern is an underground chamber approximately 138 metres (453 ft) by 64.6 metres (212 ft) - about 9,800 square metres (105,000 sq ft) in area - capable of holding 80,000 cubic metres (2,800,000 cu ft) of water. The ceiling is supported by a forest of 336 marble columns, each 9 metres (30 ft) high, arranged in 12 rows of 28 columns each spaced 4.9 metres (16 ft) apart. The capitals of the columns are mainly Ionic and Corinthian styles, with the exception of a few Doric style with no engravings. One of the columns is engraved with raised pictures of a Hen's Eye, slanted braches, and tears. Ancient texts suggest that the tears on the column pay tribute to the hundreds of slaves who died during the construction of the Basilica Cistern.