Vadim S.
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Built in the late IV century AD.
Completed in 373 by the Emperor Valens (364–378).
Initially 268 kilometres (167 miles) long, it was extended in the V century by adding another 451 kilometres (280 miles).
The aqueduct fed three large open-air cisterns in parts of the city outside the 4th-century Constantinian Walls: the Cistern of Mocius, the Cistern of Aspar, and the Cistern of Aetius altogether 607,715 cubic metres (21,461,300 cu ft) of water.