The Caves of Han-sur-Lesse are a major Belgian tourist attraction located in Wallonia on the outskirts of the village of Han-sur-Lesse.
The caves are the result of the underground erosion of a limestone hill by the river Lesse. For most of its length, it is a meandering river. Not far from Han-sur-Lesse, it abruptly plunges into a sinkhole known as the gouffre de Belvaux, forcing its way under the hill over a distance of over 1 kilometer as the crow flies before streaming through the cave complex known as the Grottes de Han.