Roman aqueduct
Rome's first aqueduct was built in 312 BC, and supplied a water fountain at the city's cattle market. By the 3rd century AD, the city had eleven aqueducts, sustaining a population of over a million in a water-extravagant economy; most of the water supplied the city's many public baths. Cities and towns throughout the Roman Empire emulated this model, and funded aqueducts as objects of public interest and civic pride, "an expensive yet necessary luxury to which all could, and did, aspire".
Valens Aqueduct
The exact date that construction on the aqueduct began is uncertain, but it was completed in 368 AD during the reign of Roman Emperor Valens, whose name it bears. The spectacular bridge section lay along the valley between the third and fourth hills of Constantinople, occupied respectively at that time by the Capitolium and the Church of the Holy Apostles. According to tradition, the aqueduct bridge was built using the stones of the walls of Chalcedon, pulled down as punishment in 366 after the revolt of Procopius. The structure was inaugurated in 373 by the urban prefect Clearchus, who commissioned a "Nymphaeum Maius" in the Forum of Theodosius, that was supplied with water from the aqueduct.