Just 6km southwest of Rochefort, the busy village of HAN-SUR-LESSE has got one thing going for it, the Grottes de Han, rue J. Lamotte 2 (whttp://www.grotte-de-han.be). Discovered at the beginning of the nineteenth century, the caves measure about 8km in length, a series of limestone galleries carved out of the hills by the River Lesse millions of years ago. The caves are actually just outside the village a little way downriver, but special trams (no extra charge) leave from a central ticket office in the heart of the village. Tours leave every half an hour during summer (hourly in April, Sept & Oct), last around an hour and are well worth it, although you visit only a small part of the cave system, taking in the so-called Salle du Trophée, the site of the largest stalagmite; the Salle d’Armes, where the Lesse reappears after travelling underground for 1km; and the massive Salle du Dôme – 129m high – which contains a small lake. After the tour, you make your own way back to the village on foot, which is a five- to ten-minute walk.
For an insight into how the caves were formed, head to the Musée du Monde Souterrain, at place Théo Lannoy 3; it’s behind the tourist office and church, across the street from the caves’ ticket office. A section of the museum explains the process, while others display the prehistoric artefacts unearthed during a series of archeological digs in and around the caves. Most were found where the Lesse surfaces again after travelling through the grottoes – among them flints, tools and bone ornaments from the Neolithic period, as well as weapons and jewellery from the Bronze Age.