The Valens Aqueduct (Turkish: Bozdoğan Kemeri, meaning "Aqueduct of the grey falcon"; Ancient Greek: Ἀγωγὸς τοῦ ὕδατος, Agōgós tou hýdatos, meaning simply "aqueduct") is a Roman aqueduct which was the major water-providing system of the Eastern Roman capital of Constantinople (modern Istanbul, Turkey).