Far from all traffic, the Lahn Cycle Path winds through an untouched and forested river valley. Then, you cycle via the Arnstein Monastery to Nassau. This town is connected to the Dutch royal family. The castle on the mountain above Nassau (built around 1120) is the birthplace of the House of Nassau, which now reigns in Luxembourg and the Netherlands. Bad Ems is considered one of the most beautiful spa towns in Germany. In the 19th century, Bad Ems steadily grew in fame, attracting more and more visitors, including many celebrities.