The remains of Diana fortress were found on the high cliff above the Danube River in the Karatas Excavation Site, in East Serbia. Diana Fortress represents the largest and the best preserved Roman Fortification /castrum/ on the Danube River. It was built of ashlar stone during the reign of of the Roman Emperor Traian, probably between 100-101 AD, at the same time when canals were constructed to enhance sailing along the Danube.
Diana Fortress features rectangle shape of dimensions 100 x 200 meters with towers on the walls. The finalization of Diana stronghold construction was at the end of the 3rd century and the beginning of the 4th century AD when towers were added on Diana fort towards the river, protecting the shore of the Danube. In the middle of the 5th century Diana Fortress was destroyed by the Huns and in 530 AD was rebuilt by Emperor Iustinian. The military camps with related objects were found beside the Diana fortress walls and the entrance gate with towers and the sacrificial necropolis and small settlement above the walls. Significant archaeological artifacts /various weapons, daily tools, marble and bronze sculptures /were found on the Diana archaeological site. They are the evidences of the great economic importance of the port of Diana fortress, as well as its strategic and defensive role on the Danube line in Roman times. In 1983, Diana Fortress was added to the Archaeological Sites of Exceptional Importance list, protected by Republic of Serbia.