The Basilica Cistern, also known as the Sunken Palace, is the largest of several hundred ancient cisterns beneath Istanbul. Built in the 6th century during the reign of Byzantine Emperor Justinian I, the cistern is an underground chamber capable of holding 80,000 cubic metres of water. It is supported by a forest of 336 marble columns, some of which were recycled from older buildings. The cistern is famous for the two Medusa heads at its northwest corner. It was used as a location for the James Bond film From Russia with Love.