From Roman times, the Rhine was the commercial artery of Europe’s heartland. Noblemen, and the merely rich, built their castles, palaces and feudal estates along it.

In Germany’s Rhine Valley, several centuries-old castles sit just minutes from one another, and visiting them can be particularly enjoyable as the foliage changes color in the fall.

Vineyards along the Rhine River, Germany. These performers board at a town or a lock stop and although their performance may only be an hour or so long, they must wait for the next lock to get off.

This historic 12th-century Stahleck Castle, towering above the Rhine valley, has had an ironic fate. While once home royals it now opens its rooms to backpackers as a hostel.

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.

A few companies pair the Rhine with the Main; all offer two-week cruises to Budapest, a journey that takes in the Rhine, Main and Danube rivers, and also the Main-Danube Canal.

There's a little narration, and studious passengers use handy Rhine map-guides to identify the sights we pass. All along the Rhine, it seems each castle and every rock come with a story.