Koblenz
This 2,000-year-old city, where the Teutonic Order founded one of its first commanderies in the 13th century, lies on the convergence of the Moselle and Rhine Rivers. Hop on a cable car, one of the city's most popular attractions, for stunning city-wide views, or cruise down the Rhine to spot some of Koblenz's magnificent fortresses and castles, including the Ehrenbreitstein Fortress and Schloss Stolzenfels.