Embark on a unique exploration with a mountain bike through the Sibbergroeve in Valkenburg. Be sportingly amazed in this underground world. After descending a staircase of 163 steps and 40 meters deep, you will receive the necessary instructions from your guide, your bike, and helmet! Your journey can begin... about 2 hours through the caves along low winding bends and high expansive corridors. Wow! Your guide determines the route and takes you on this adventure. You can join this tour solo or in a group. The caves are dry and always 12 degrees. So pleasantly cool in the summer and warm in the winter. Highly recommended!