The Basilica Cistern, Istanbul, Visitor Guide & Things to Do Nearby

The Basilica Cistern is the largest of the several hundred ancient cisterns beneath Istanbul, Turkey. Built in the 6th century under the Byzantine emperor Justinian I, this vast underground water reservoir sits a short walk southwest of Hagia Sophia in the historic Sultanahmet area, and visitors can walk through it today.

The story behind it

The cistern was built in the 6th century, during the reign of Justinian I, as part of the water storage system of Byzantine Constantinople. It lies about 150 metres southwest of Hagia Sophia, on the historic peninsula of Sarayburnu. Today it is kept with only a little water, so that the public can move through the space.

Its best-known story belongs to two column bases in the northwest corner, which reuse blocks carved with the face of Medusa. No one knows where the two heads came from, though they are thought to have been taken from a late Roman building. Tradition says they were set sideways and upside down to cancel the Gorgon's gaze. The more likely explanation is plainer: the blocks were treated as rubble, reused in a place never meant to be looked at.

What to look for

• Find the two Medusa blocks in the northwest corner, where they serve as bases for columns.
• Notice how one head lies sideways and the other is upside down, and decide for yourself whether it was superstition or simple reuse.
• Look at the forest of columns stretching into the dim light, many of them clearly gathered from earlier buildings.
• Pay attention to the quiet and the cool air, which make the space feel very different from the busy streets above.

Tips for your visit

• Allow about 30 to 45 minutes inside, longer if you like to take photographs in low light.
• Check current opening hours and ticket arrangements before you go, as queues can be long at busy times.
• Go early or late in the day if you want a calmer visit, since this is one of the most popular sights in Sultanahmet.
• Hagia Sophia is only a few minutes away on foot, so the two sights combine easily into one outing.

See it on a quest

The cistern is a natural stop on Mysteries of Constantinople: An Istanbul Riddle Quest. You reach it on foot as one stop of a longer route through the old city, the app tells you about each place as you arrive, and you solve a puzzle on the spot. That turns a quick look into something more attentive. One ticket covers the whole group, and you can start whenever suits you, with no guide and no set departure time.