There are several popular rivers and waterways in Europe for sightseeing across the continent. Each river provides a unique experience as they have different cultural heritage and historical significance throughout the region. There are several viable routes available for the intrepid and discerning traveler who wishes to take in the sights while enjoying the comforts and luxury of a cruise. With this in mind, here are some of the best water routes to consider for European river cruises:

1. Central Europe and the Danube river
The navigable Danube is one of the most spectacular rivers with its origins in the Black Forest of Germany. It moves east towards the Black Sea and either touches the borders or navigates through several European countries like Serbia, Croatia, Austria, Moldova, Ukraine, Hungary, and Bulgaria. The cruise usually sails between Regensburg and the Black Sea, and the cruise liners tend to focus on the parts between Budapest and Passau or Bucharest and Budapest. The former covers several spectacular locales like the Wachau, a valley which is a UNESCO World Heritage site, and also passes through several breathtaking capitals like Vienna, Budapest, and Bratislava.

Moreover, tours to Melk, Krems, Durnstein, and Salzburg from Linz are also popular with the cruise docking at the ports, allowing plenty of free time to explore. Between Budapest and Bucharest, passengers can see Hungary, Serbia, Bulgaria, and Romania and even get a chance to interact with friendly locals.

2. Germany and the Main
The Main river lies entirely in Germany. It features several ports that have an interesting history with beautiful sites to visit. These ports include Miltenberg, Wertheim, Bamberg, and Wurzburg. Walking in these towns and admiring the architecture is very enjoyable and many tourists also use the Main river as a link between the Danube and Rhine.

The Main-Danube canal allows tourists a day-long visit of Nuremberg, which has historical significance. The width and height of the ships are directly related to the locks on these canals. Because the locks are so narrow and there are so many overhead bridges, the river cruises must also correspond with the width and height in order to navigate smoothly.

3. Switzerland to the Netherlands and the Rhine river
The Rhine river has its source in Switzerland and generally flows North-west before flowing into the North Sea, which is close to Rotterdam. The river cruises here move between Basel in Switzerland and Amsterdam. There is also a link between the Rhine and Main rivers wherein passengers can visit the city of Strasbourg, which has an interesting location.

The prime focus of this route is the many castles along the Rhine that are world-famous among travelers. The cruise also stops near the cathedrals of Cologne and the windmills of Kinderdijk.

There are many more European river cruises, each with its own unique itinerary. You can research a bit online or speak to a travel agent for a plan that suits you best.