The Oder is a 56-kilometre-long river in Lower Saxony, Germany, and a right tributary of the Rhume. Its source is in the Harz mountains, near Sankt Andreasberg. It flows southwest through Bad Lauterbe
Confluence of Sieber (left) in the Oder (right) at Hattorf
At 925 m above sea level, the Achtermannshöhe in the Harz National Park is the third highest mountain in Lower Saxony and the fourth highest in the Harz mountains.
Summit of the Achtermannshöhe
Achtermannkuppe from the Rehberg. In the background are buildings on the Brocken Plateau.