Valens Aqueduct

The Valens Aqueduct (Bozdoğan Kemeri, "the aqueduct of the falcon") was completed in 368 CE by the Roman emperor Valens, bringing water from the Belgrade Forest (Belgrat Ormanları, north of the city) into the central imperial quarter. It remained the city's primary water-supply structure until the 19th century — nearly 1,500 years — and survives intact in the middle of modern Istanbul.

The aqueduct is a stack of arches — over 900 meters long in its full original length, with the visible main span crossing Atatürk Boulevard between Süleymaniye and Şehzadebaşı at 18 meters tall. The arches are double-tiered in the central span, single-tiered elsewhere. The stonework is rough but impressive; the original Roman brick courses are visible alongside later Byzantine and Ottoman patches and repairs.

There's no admission, no museum, no official entrance — the aqueduct is integrated into the urban fabric and visible from multiple viewpoints. The best photo angle is from the south end at Atatürk Boulevard, where you can see the double-tiered section with the Süleymaniye rising behind it. The park around the base is a popular walk for locals.

Free, 24/7, illuminated at night. The Valens Aqueduct is part of a free and easy 30-minute walking tour of the area between the Süleymaniye, Şehzade, and Zeyrek Mosques, with the aqueduct as the central sightline.