MergelRijk is an underground visitor attraction in Valkenburg, South Limburg, offering an engaging introduction to the region’s caves and marl limestone. Designed for visitors of all ages, it combines local history, education, creativity and entertainment in a distinctive cave setting. An audio tour, guided by the character Jan, lets guests explore at their own pace while learning about how the caves formed, how marl was mined, and how people have used the material and underground spaces over time.

The visit includes a cave walk and a range of activities presented along the route. Visitors can try working with marl to make a souvenir, discover 3D cave paintings and view sand sculptures. The experience also features interactive activities for children, including a search for fossilized shark teeth, with dinosaur displays among the attractions highlighted by families. MergelRijk describes itself as suitable for both adults and children and says a visit takes around an hour and a half, often longer with young children.