Basilica Cistern

The Basilica Cistern, known in Turkish as Yerebatan Sarnıcı, is one of Istanbul’s most impressive underground monuments. Located close to Hagia Sophia, it offers a remarkable glimpse into the engineering skills and architectural traditions of the Eastern Roman Empire. The cistern was built in the 6th century during the reign of Emperor Justinian I. It was constructed to store and supply water for the Great Palace of Constantinople and other important buildings in the surrounding area. Its name comes from a large basilica that once stood above the site. The vast underground chamber is supported by 336 marble columns arranged in long, symmetrical rows. Most of the columns are approximately nine metres high and were collected from older Roman buildings across the empire. Their different styles and decorative details give the cistern a unique architectural character. One of its most famous features is the pair of Medusa heads used as column bases in the north-western corner. One head is positioned sideways, while the other is upside down. Their original purpose and unusual placement remain uncertain, although they may have been reused simply as practical building materials. The soft lighting, shallow water and reflections between the columns create a mysterious and atmospheric interior. Raised walkways allow visitors to explore the structure while viewing its brick vaults, marble columns and carefully designed water system. The Basilica Cistern continued to supply water after the Ottoman conquest of Constantinople, although it gradually lost its original importance as new water systems were developed. It was later cleaned, restored and opened to the public as one of Istanbul’s most distinctive historical attractions. Today, the Basilica Cistern combines ancient architecture with modern artistic installations and lighting. Together with Hagia Sophia, Topkapı Palace and the Blue Mosque, it forms part of the extraordinary historical landscape of Sultanahmet. Visitors should allow enough time to experience its calm atmosphere and observe the different columns, carvings and Medusa heads throughout the underground chamber.