The Djerdap Gorge is composite and consists of four smaller gorges and three valleys: Golubac Gorge, Liubcova Valley, Gospodjin Vir Gorge, Donji Milanovac Valley, Kazan Gorge, Orșova Valley and Sip Gorge. A large number of deep whirlpools and giant potholes exist in this sector of the Danube. Some of them are deeper than 80 m, so the Danube’s riverbed locally lies below the sea level.