The Baltic Sea Feeder is a network of rivers that feed into the Baltic Sea. The Oder, Elbe, Ural, LIEU and Peene are all part of this network. The Oder is a river in Central Europe that flows through Germany and Poland. The Elbe is a river in Central Europe that flows through Germany and the Czech Republic. The Ural is a river in Russia that flows from the Ural Mountains to the Caspian Sea. The LIEU is a river in Russia that flows from the Valdai Hills to the Gulf of Finland. The Peene is a river in Germany that flows from Mecklenburg-Vorpommern to the Baltic Sea.