The Valens Aqueduct is a Roman aqueduct in Constantinople and a major source of fresh water for the city during the 16th century.


Completed by Roman Emperor Valens in the late 4th century CE, it was used and repaired by Byzantine, Latin and Ottoman dynasties until well after Sultan Mustafa's final major restoration in 1679.

The aqueduct continued to be used well into the 19th century, bringing small amounts of fresh water into the city until it was finally made obsolete by the introduction of pipes. Nowadays, the landmarks is about 600 meters in length, roughly half its original size.