The fort Großfürst Konstantin in the Karthause district of the city of Koblenz in the state of Rhineland - Palatinate. The fort is located on the Hunsrück mountain in the West of Koblenz main train station. The fort is part of the former stronghold and fortress of the city, overlooking the Rhine river. During the second World War, it was used for air raid protection and as a bunker