Roman Aqueduct (Iznik)
It was built during the Roman Empire period to meet the water needs of the city of Nikaia (Iznik). The spring coming from the Katırcı İni at the foot of Elmalı Mountain in the east of the city and the cave in the Berberkaya extension was carried to Lefke Kapı and from there into the city with the help of aqueducts. The aqueducts, built by the Roman emperor Hadrian (117-138 AD), were used until recent history. The channel depth of the aqueduct, which is approximately 1 km long, is 0.50 meters and its width is 0.45 meters. From an unearthed inscription, it is understood that importance was given to the protection and cleanliness of the spring and water system in Nikaia during the Roman Imperial period. According to the inscription in question, by Hadrian; Those living around the waterway should not enter the waterway and should not damage the canal and surrounding trees; It was stated that if they did so, they would have to pay a fine.

The water coming from the source is first settled and stored in a pool before being transported to the city through aqueducts; The rubble was then transported to the city with the help of aqueducts built with stones, bricks and spoliated materials. During the Byzantine and Ottoman periods, the arches actively met the water needs of the city. During the Ottoman period, a fountain with a tank was built on the part of Lefke Gate overlooking the city center. The aqueduct and fountain structure were used until the 20th century. Most of the arches belonging to the water system, which have been repaired many times since the time they were built, have been filled and turned into walls. The carrier arches that form the water system are most clearly seen in the parts near Lefke Gate.