A good day trip from Cologne can be to travel south to Koblenz. This trip offers beautiful scenery along the Rhine River. Once you arrive in the town, head for the Deutsches Eck, or German Corner. This is where the Rhine and Mosel rivers meet, and the spot offers a sight of the water and surrounding hills. Also trek up to Ehrenbreitstein, a huge fortress on the hill overlooking Koblenz. This also holds a youth hostel and the Landesmuseum Koblenz.