Koblenz is a good place to stay overnight if you want to see the Rhine valley. We found the hotel near the train station, but had no idea what to see in the city, so we just went for a walk to the downtown.
Koblenz pleasantly surprised us. Despite the fact that the city is not touristic, it's a very nice place to walk because of long waterfronts. The main attraction is the German Corner (Deutscher Ecke), the name of a headland in Koblenz where the Moselle river joins the Rhine river. In 1897, nine years after the death of the German Emperor William I, the former emperor was honored with a giant equestrian statue. After formation of the Federal Republic of Germany and the German Democratic Republic in 1949, the country was divided into a capitalist West and a communist East. In order to express the deep wish for a united Germany, president Theodor Heuss turned the German Corner into a monument to German unity.
On the other side, on the hill, you can see the Ehrenbreitstein Fortress, which can be reached by city cable car. It has been working for several years and is the largest cable car in the plain part of Europe, the length is 850 meters. One of the 18 cars has a glass floor, we recommend choosing this one :) Check out the official website for opening hours and prices.
Getting there: By regional train from Cologne the trip lasts 1 hour 10 minutes, from Frankfurt 1 hour 45 minutes.