March was one of the driest in Germany on record and low water levels on the Rhine River mean ships cannot carry full loads.

The Danube runs neck and neck with the Rhine as being the most popular waterway for a river cruise. It flows through, or borders, 10 countries, which is more than any other river in the world.

The 65km-stretch of the Middle Rhine Valley, with its castles, historic towns and vineyards, graphically illustrates the long history of human involvement with a dramatic and varied natural landscape.