Valens
Aqueduct

Stones Carrying the Flow of Time

"The Valens Aqueduct is not just a waterway; it is a massive infrastructure project shared by Roman, Byzantine, and Ottoman civilizations."

Completed during the reign of Roman Emperor Valens (368 AD), the aqueduct was designed to bring water from the Belgrade Forest to the city's central points, specifically the Basilica Cistern and Binbirdirek Cistern. Today, Ataturk Boulevard passes directly beneath the arches, with modern Istanbul traffic flowing through the legs of this ancient giant.

A Bridge Between Two Empires: The Construction Story

Work on the water line that would become the Valens Aqueduct began under Emperor Constantius II in the mid-4th century, but the structure that still crosses Fatih today takes its name from his successor. Emperor Valens (r. 364-378 AD) pushed the project to completion around 368 AD, and the wider water system, including the monumental Nymphaeum Maius fountain in the Forum of Theodosius, was formally inaugurated in 373 AD. The aqueduct carried water from the forests northwest of the city into the heart of Constantinople, feeding the great open-air cisterns of Mocius, Aspar, and Aetius, as well as the underground Cistern of Philoxenos, better known today as the Binbirdirek Cistern. Together with the Basilica Cistern, these reservoirs formed the backbone of Constantinople's Roman water supply, a system that kept the city alive through sieges, droughts, and centuries of growth.

Roman Engineering in Stone and Brick

What makes the Valens Aqueduct one of the great surviving examples of a Roman aqueduct is its scale and its double-tiered construction. The bridge originally ran about 971 meters across the valley between the hills now occupied by Istanbul University and Fatih Mosque, and roughly 921 meters of that span still stand today. At its tallest point the structure reaches close to 29 meters, carried on two stacked rows of arches (a lower, sturdier tier and a lighter upper tier) built from alternating courses of ashlar stone and brick, a technique typical of late Roman engineering in the eastern Mediterranean. Altogether the surviving section counts dozens of arches marching across Ataturk Boulevard, making it one of the most recognizable examples of Roman aqueduct architecture anywhere in the world and a rare structure of this type still standing in the middle of a living, modern city.

From Byzantine Repairs to Mimar Sinan's Additions

The aqueduct's long life is really a history of continuous repair. Byzantine emperors restored it after earthquakes and after damage from the Avar siege of 626, with Emperor Constantine V undertaking major repair work in 758 to restore the long-distance water supply. Centuries later, under the Ottomans, Sultan Suleiman the Magnificent commissioned his chief imperial architect, Mimar Sinan, to overhaul and expand the whole Istanbul water supply network in the 1550s, adding new lines from the Belgrade Forest and rebuilding weakened arches of the aqueduct itself. Further repairs followed under Sultan Mustafa II, whose restoration of several arches in 1696-97 is still marked by an inscription on the structure. Part of the aqueduct was removed in the early 20th century to allow a new boulevard to pass through Fatih, which is why the surviving bridge, known locally as Bozdogan Kemeri, is somewhat shorter than the Roman original.

Where to Find It and How to Get the Best Photos

The aqueduct sits squarely in the Fatih district, spanning Ataturk Boulevard between the Saraçhane and Zeyrek neighborhoods, a short walk from the Suleymaniye Mosque and the Zeyrek Mosque (the former Pantokrator Monastery). Sarachane Park, laid out right beside the arches, is the easiest and most popular spot for photographs, offering an open, level view of the double arcade with no traffic in the frame. For a different angle, the sloping streets around Zeyrek give an elevated view over the aqueduct toward the Golden Horn, while the structure is dramatically lit after dark, when the stone arches glow against the night sky and the boulevard traffic below adds a striking contrast between ancient and modern Istanbul. The nearby Sehzade Mosque, built for the son of Suleiman the Magnificent, and the bustling streets of Fatih make this whole stretch one of the richest short walks for anyone interested in the layered history of Constantinople's Roman, Byzantine, and Ottoman past.