The European Border River is a river that forms part of the border between Germany and Poland. It is composed of two rivers, the Oder (4 letters) and the Neisse (6 letters). The Oder is the larger of the two rivers, and it flows through Germany, Poland, and the Czech Republic before emptying into the Baltic Sea. The Neisse is a tributary of the Oder, and it flows through Germany and Poland before joining the Oder near the city of Guben. Together, the Oder and Neisse form the border between Germany and Poland.