Basilica Cistern

"A journey through this ancient underground waterway takes you along dimly lit walkways that weave around 336 marble columns rising 26 feet to support Byzantine arches and domes." Full review

"When those Byzantine emperors built something, they certainly did it properly!" Full review

"Built more than 1400 years ago under the direction of the Byzantine Emperor Justinian—the same guy responsible for the Hagia Sophia—this underground cistern once stored water for the whole city." Full review

"A city as ancient as Istanbul has many layers of history, and you’ll have to go below the surface to see the Basilica Cistern, the largest of the underground cisterns." Full review

"What the Ottomans called Yerebatan Sarayi (Sunken Palace) is in fact a 6C Byzantine underground cistern that supplied water to the palace of Emperor Justinian." Full review

"The primary water reservoir for Constantinople, the Basilica Cistern is cathedral-esque and a sight to see...it is supported by 336 columns and can hold up to 17.5 million gallons of water."