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On foot · Full day ~4 km
Valkenburg Above & Below
One compact town, five ways underground: castle ruins, velvet caves, a coal mine and a marl labyrinth — finish soaking in thermal water.
Valkenburg sits on a Swiss cheese of marl passages, and this walk strings the best of them into one day. Start on the castle hill, descend through the Velvet Cave's secret stairs, then pick your favourite underground world: the vast municipal caves, a working coal-mine tour led by ex-miners, or MergelRijk's sculpted galleries. It is always 11°C down there — end the day the opposite way, in the open-air thermal baths.
- 1
Valkenburg Castle Ruins
Valkenburg · €€
The only hilltop castle ruin in the Netherlands — start with the view.
- 2
Fluweelengrot (Velvet Cave)
Valkenburg · €€
Descend straight from the castle through the Velvet Cave's escape passages.
- 3
Gemeentegrot (Municipal Cave)
Valkenburg · €€
The big one: a marl labyrinth toured on foot or by little train.
- 4
Valkenburg Coal Mine
Valkenburg · €€
Ex-miners lead you through a real coal mine — helmets on.
- 5
MergelRijk
Valkenburg · €€
Marl sculptures and the gentlest cave for younger kids.
- 6
Thermae 2000
Valkenburg · €€€
Thermal baths on the Cauberg to warm up after a day at 11°C.