The Valens Aqueduct was the major water-providing system of medieval Constantinople. Restored by several Ottoman Sultans, it is one of the most important landmarks of the city. The aqueduct stands in the quarter of Fatih, and spans the valley between the hills occupied today by the Istanbul University and the Fatih Mosque. The surviving section is 921 meters long, about 50 meters less than the original length. The Atatürk Bulvarı boulevard passes under its arches.