Run by Istanbul Metropolitan Municipality's cultural enterprise Kültür A.Ş. and named the third most visited place in Turkey by international tourists, the Basilica Cistern will undergo extensive restoration for the first time in 1,500 years.The restoration project by Hera Restoration is planned to last for 450 days and end on March 11, 2018. However, the historical Basilica Cistern in Istanbul's Sultanahmet will be open to visitors during restoration.According to the contract, the entrance and exit doors of the cistern will be redesigned, with the small size of the current entrance door allowing only a few people going in together causing tourists to face long waits in ques.At the end of the restoration work, the Basilica Cistern will have a new waiting lounge made from glass and the exit door will be renovated in a way that is suitable for a museum.The Basilica Cistern is 140 meters in length and 70 meters in width. There are 52 stone stairs to reach the heart of the cistern and it features 336 columns, each nine meters tall, which are presumed to be built from the stones of older buildings. The starting point of all ancient Roman roads is located inside the park next to the Basilica Cistern and indicated by the Milion Stone, which dates back to 4th century.The walking path on which the tourists walk on as they tour the historic cistern used to get wet all the time during rainy days so new isolation methods will be done to the necessary parts of the cistern to keep visitors safe.The concrete platform built inside the cistern will be removed and a new platform, to be made from modern materials, will be placed inside the Basilica Cistern.The fortification of the columns, walls and vaults will be carried out according to the restoration report.Furthermore, mistakes made in previous restorations -concrete fortifications for walls and columns for instance- will be removed and redone according to their original state.The starting point of all ancient Roman roads is located inside the park next to the Basilica Cistern and indicated by the Milion Stone, which dates back to 4th century. It was considered the center of the world and a water gage dating back to 16th century has also been included in the restoration works.The Basilica Cistern is 140 meters in length and 70 meters in width. There are 52 stone stairs to reach the heart of the cistern and it features 336 columns, each nine meters tall, which are presumed to be built from the stones of older buildings.295 columns of the cistern are open to visit while 41 columns are allocated in a section which is closed off to the public. The Basilica Cistern covers an 8,678 square meter area and 7,648 square meters of its entire complex is open to tourists. However, 1,030 square meters of the cistern cannot be reached on foot. The cistern has a capacity to store 100 tons of water.Built by Byzantine Emperor Justinian I in 542 and recognized as the oldest cistern in the world, the Basilica Cistern was open to visitors by the Istanbul Metropolitan Municipality following a thorough cleaning in 1987.