Underground cistern built during the reign of the Roman emperor Justinian I in the sixth century CE, with later restorations during the Ottoman period. The subterranean space is broken up by 336 columns, as well as two Medusa heads used as column bases. It is located next to Hagia Sophia.

See:

İBB Kültür A.Ş. "Yerebatan Sarnici Basilica Cistern." Accessed February 13, 2014.

Istanbul Metropolitan Municipality. "The Basilica Cistern." Accessed February 13, 2014.