The Basilica Cistern Museum is one of the most important cultural assets where we can trace the traces of glorious Istanbul history. This grand underground cistern, built by Eastern Roman Emperor Justinian I (527-565), is nicknamed “Yerebatan Sarayı” (Sunken Palace) among the public due to its numerous marble columns rising from the water. It is also known as “Bazilika Sarnıcı” (Basilica Cistern) by some, as it was built on the site of the former Stoa Basilica, which was a basilica.

With its 80,000-ton water storage capacity, Yerebatan Cistern is the largest covered cistern in the city and stands out with more reclaimed supporting elements compared to other covered cisterns. Covering an area of approximately 10,000 square meters, this colossal structure has a rectangular shape with a length of 140 meters and a width of 70 meters.

According to written sources, the cistern used to distribute water from waterways and rain to the Great Palace, where the emperors resided, and the surrounding buildings, meeting the city’s water needs for hundreds of years. It also received water from one of the historical aqueducts called the Hadrianus Aqueduct.

Inside the cistern, there are 336 columns, each measuring 9 meters in height. These columns are erected at 4.80-meter intervals, forming 12 rows, each containing 28 columns. Carved from various types of marble, most of the columns consist of a single piece, while some are composed of two parts.

The capitals of the columns exhibit different features. Some reflect the “Corinthian” style, while others stand out with plain, unadorned capitals. Except for a few of the columns with angular or fluted shapes, most of them are observed to be cylindrical.

The cistern’s 4.80-meter-thick walls made of bricks and its brick-paved floor are rendered impermeable by a thick layer of mortar made from “Horasan” lime.