The Sava is a major river in southeastern Europe, flowing through several countries, including Slovenia, Croatia, and Serbia. It is approximately 990 kilometers long and is a significant tributary of the Danube River. The Sava plays an essential role in the region's ecology and economy, providing water for agriculture and serving as a transportation route. In Serbia, the Sava River forms part of the border with Croatia and flows through cities like Belgrade, where it meets the Danube. The river is vital for local communities, offering recreational opportunities and supporting biodiversity in the surrounding areas.