4 Best Sights in The Rhineland, Germany

The best-preserved Roman structure in Trier was originally a city gate built in the 2nd century (look for holes left by the iron clamps that held the structure together). The gate served as part of Trier's defenses, and was proof of the sophistication of Roman military might and its ruthlessness. Attackers were often lured into the two innocent-looking arches of the Porta Nigra, only to find themselves enclosed in a courtyard. In the 11th century the upper stories were converted into two churches which remained in use until the 18th century. The tourist office is next door.

Looking west along the river from Bingen, you can just about spot the Mäuseturm, perched on a rocky island near the Binger Loch. The name derives from a gruesome legend. One version tells that during a famine in 969 the miserly Archbishop Hatto hoarded grain and sought refuge in the tower to escape the peasants' pleas for food. The stockpile attracted scads of mice to the tower, where they devoured everything in sight, including Hatto. In fact, the tower was built by the archbishops of Mainz in the 13th and 14th centuries as a Mautturm (watch tower and toll station) for their fortress, Ehrenfels, on the opposite shore (now a ruin). It was restored in neo-Gothic style by the king of Prussia in 1855, who also rebuilt Burg Sooneck, but you can't go inside.

A squat tower is all that remains of the palace built by the Berg family, which ruled Düsseldorf for more than five centuries. The tower also houses the SchifffahrtMuseum, which charts 2,000 years of Rhine boatbuilding and navigation.