Kolubara is a river located in Serbia, flowing through the central part of the country. It is approximately 70 kilometers long and is a tributary of the Sava River. The river is known for its picturesque landscapes and plays a significant role in the local ecosystem. The Kolubara basin is also notable for its rich coal deposits, which are exploited in the Kolubara coal mine. This mine is one of the largest in Serbia and contributes significantly to the country's energy production. The region surrounding the river is characterized by agriculture and small towns, making it an important area for local communities.