The Aqueduct of Valens (also known as the Valens Aqueduct or Bozdoğan Kemeri in Turkish) is a Roman aqueduct located in Istanbul, Turkey. It was built in the 4th century AD by the Roman Emperor Valens to bring water to the city from the Belgrade Forest, which is located several kilometers to the north. The aqueduct consists of a series of arches made of brick and stone, and is nearly 2 kilometers (1.2 miles) long. It is considered one of the most important examples of Roman engineering in Istanbul and is a popular tourist attraction in the city. The aqueduct is located in the Fatih district of Istanbul, near the walls of the ancient city.