The Grotbiken tour is a bicycle tour of some of the caves in Valkenburg. The route of the tour is quite gentle, and suitable for cyclists of all ages and fitness levels. Your guide will take you through the cave showing you the most interesting and beautiful areas, and explaining the history of the caves, which begins almost 70 million years ago. The caves are some of the most interesting features of this part of the country, but a guide is required at all times as people can quite easily get lost in the massive network of tunnels.
