This is one of the best-preserved surviving Roman ports. It stood on the old course of the river Natisone/Torre, which skirted the ancient city to the east and was almost fifty metres wide here. The structures were excavated in the 1930s. They spanned over 300 metres in length along the right bank of the river, backing on to the eastern flank of the Republican city walls. Built over an older construction, the river port was completely restructured at the beginning of the 1st century ad, with a new complex of wharfs and a long building behind that opened on to the river. Three ramps at an angle to the wharfs provided a link to the city road network. Constantine the Great carried out further work, although just a few years later, the wharfs would disappear under the new city walls, and as the channel narrowed, the port gradually fell out of use.