Weilburg is a small town on a dramatic loop of the Lahn river in Hesse, with a baroque Schloss Weilburg perched on the ridge above the water. The palace, once the residence of the Counts of Nassau-Weilburg, has seven terraced gardens cascading down the hillside to the river and is one of the finest baroque ensembles in the region. The Schlosskirche within the complex is regarded as one of Germany's most significant Protestant Baroque church buildings.
The town's most unusual feature is the Weilburg Ship Tunnel, Germany's only shipping tunnel, bored through the rock beneath the old town in the 1840s to allow boats to bypass the Lahn's tight loop. Three tunnels run side by side through the same hillside — one for the railway, one for road traffic, and one for water — which is believed to be unique in the world. You can walk through the water tunnel or canoe the Lahn itself — the stretch around Weilburg is one of the most popular paddling routes in central Germany.
The old town is compact and attractive, with half-timbered houses and a mining museum that recalls the region's iron-ore past. The Kristallhöhle in Kubach, a few kilometres away, is described as unique in Germany for its calcite crystal formations and is worth combining with a day in the town.