For 10 points, identify this river which defines part of the Germany-Poland border and is the second-longest in Poland.
Towns along this river include Police, Opole, and Oglow, and this river splits into a western, canalized portion and an eastern portion that goes through Lake Dabie before it flows into the Szczecin Lagoon. A canal near the city of Eisenh?ttenstadt connects this river to the Spree. Some of this river's tributaries include the Bober and the Bartsch. Along with the Niesse River, this river helps define an international border fixed by the Potsdam Conference, and it eventually flows into the Bay of Pomerania. For 10 points, identify this river which defines part of the Germany-Poland border and is the second-longest in Poland.
Towns along this river include Police, Opole, and Oglow, and this river splits into a western, canalized portion and an eastern portion that goes through Lake Dabie before it flows into the Szczecin Lagoon.
Oder River