Velika Morava or Morava only, is a river in Serbia. It arises from the merging of the Western and Southern Moravas to the city of Stalaca. It is rolled into the Danube in the area between Smederevo and Kostolac. Morava is along with the West Morava, the largest Serbian river. The length of the Great Morava is 185 km, with the Western Moravia (the length of the tributary) is 493 km.South Morava, which is the main source of water for Morava, is longer, but due to the regulation of the riverbed and melioration works, it has now been shorter. Regulatory works have been done on all three Moravas, so they are all significantly reduced. At one time this river was over 600 km long. Today, the furthest water source for the Moravian basin is the source of the Ibar River, the right and largest tributaries of the Western Morava. Ibar springs in Montenegro and together as a system Ibar-West Morava-Velika Morava represents a river system of 550 km long, and as such is the longest waterway on the Balkan Peninsula.In the past centuries, it was famous for its incomprehensible forests, but nowadays nothing is left of the big trees (shrubs).The Great Moravian tributaries are short in length. Jasenica is the longest (79 km) and the others are rarely over 50 km. The right tributaries are: Jovanovačka Reka, Crnica, Ravanica, Resava and Resavica (or Resavčina). Left tributaries are more numerous, including: Kalenic River, Lugomir, Belica, Osaonica (or Osanica) Lepenica, Raca, and Jasenica. Many of them are not rich in water, but during the rainy years they cause great floods, which is the main problem of the entire Moravian basin. Before the casting into the Danube, the Great Morava is broken, making a 47 km long sleeve under the name Jezava, which flows into the Danube separately in the city of Smederevo after joining the long (51 km) river Ralj on the left.