Nearby the Hagia Sophia in Istanbul is a deep underground structure the size of a Wal-Mart, the Basilica Cistern, that built in the 6th century under the Byzantine Emperor Justinian, where one can have lunch where once 7 thousand slaves labored to provide a safe place to store cool, fresh water for the Great Palace of Constantinople, fed via 2 aqueducts from forest streams outside the city. With a capacity of nearly 3 million cubic feet of water, the cistern’s walls are 13 feet thick and the vaulted roofs are supported by 336 30-foot high columns, brought from throughout the country and a few, like the two columns with sideways and upside-down Medusa sculptures, are thought to be from Roman ruins near the site. The cistern was once traversed by tourists in boats, but today a network of raised walks enabled those who find it to wander through the hauntingly lit columns. The cistern has been repeatedly repaired through the centuries, and was last used to supply water to the Topkapi Palace, but today only a few feet of water remain. Two contemporary films have used the cistern as a setting, From Russia with Love in 1963 and The International in 2009. It’s a nice place to cool off anfter a tough day of shopping in the bazar. .