Basilica Cistern (Yerebatan Sarnıcı)

The Basilica Cistern lies under the Sultanahmet area of Istanbul, a short walk from Hagia Sophia. It was built in the 6th century under the Byzantine emperor Justinian I to store water for the Great Palace and nearby buildings, and it is the largest of the several hundred ancient cisterns beneath the city.

It takes its name from a great public basilica that once stood above it. The Turkish name, Yerebatan Sarnıcı, means the sunken cistern. After the Ottoman conquest it slowly fell out of mind until the French scholar Petrus Gyllius tracked it down in 1545, after hearing that local residents drew water and even caught fish through holes in their floors.

The cistern measures about 138 by 65 metres and could hold around 80,000 cubic metres of water. Its brick vaults rest on 336 marble columns, each about 9 metres high, arranged in 12 rows, many of them reused from older buildings. In the far corner, two columns stand on large carved Medusa heads, one placed sideways and one upside down, whose origin is unknown. Another column is carved with a pattern of tear shapes.

More than 50,000 tonnes of silt were removed in the 1980s, and the cistern opened to visitors in 1987. A restoration from 2020 to 2022 added earthquake strengthening, new walkways and LED lighting, and the space now also hosts art installations. It forms part of the Historic Areas of Istanbul World Heritage Site and has appeared in the James Bond film From Russia with Love and Dan Brown's novel Inferno.

Daytime entry costs 1,950 lira and the evening Night Shift 3,000 lira, and queues form at midday in summer. The walkways are dim and damp, so wear shoes with grip. Allow 30 to 45 minutes.

Medusa heads and the Weeping Column

Walk the raised platform toward the north-west corner to reach the two Medusa heads, then return along the opposite side to see the Hen's Eye column, also called the Weeping Column, carved with tear-like shapes and usually damp to the touch. Fish still swim in the shallow water below the walkways.

The cistern has closed at times for maintenance, and the operator has pointed visitors to the smaller Theodosius Cistern (Şerefiye Sarnıcı) nearby during those periods, so check the official site on the day. Hagia Sophia is about 150 metres away, and the Sultanahmet tram stop on the T1 line is a two-minute walk.