Oder is a river in Central Europe that flows through Poland and Germany. It is approximately 854 kilometers long and is one of the longest rivers in the region. The river originates in the Sudetes mountains and eventually empties into the Baltic Sea. The Oder serves as a natural border between Poland and Germany for a significant portion of its length. It is an important waterway for transportation and trade, supporting various industries along its banks. The river also provides habitats for diverse wildlife and recreational opportunities for local communities.