Aqueduct of Valens

The Aqueduct of Valens is a late-Roman and Byzantine water infrastructure monument dating to around 368 AD, its double-tiered arches still spanning the busy Atatürk Bulvarı in central Istanbul. Built under Emperor Valens to channel fresh water from the forests of Thrace into Constantinople, it originally ran for just over a kilometer across the European hills of the city. Earthquakes and sieges destroyed sections over the centuries; Ottoman sultans repeatedly restored it, most recently in 1697, continuing to use it as part of the city's water system. Of the original structure, roughly 800 meters survive today, standing up to 18.5 meters tall. Visitors experience a striking juxtaposition of heavy ancient limestone arches looming directly above modern traffic — a reminder that Istanbul has been continuously inhabited and rebuilt for over two millennia.