Coordinate: 41º00’57.47’’K 28º57’18.08’’D Height: 52 m
It was built in years between 368 and 373 in Eastern Roman Emperor Valens (364-378) period. It was built on the lower area between the third and fourth hill over the water way. The water was brought from the dams outside the walls by pipes and channels. It was 971 meter long with the parts demolished by the Conqueror and the prince. It continued functioning after being repaired in Ottoman era.