The 'marl' stone found in these caves is actually compressed sea sand and shells from the Late Cretaceous period, roughly 65 million years ago.
The caves are located in a region that was once a shallow, tropical inland sea.
The temperature inside the cave remains consistently cool, typically around 12 degrees Celsius, regardless of the surface weather.
Many of the sculptures are created by professional sand and stone sculptors invited for special exhibitions.
The site uses a specific type of 'mergel' (limestone) which is soft enough to carve with hand tools but hardens slightly upon exposure to air.
MergelRijk is situated within the complex of the Daalhemergroeve, an extensive network of man-made tunnels dating back centuries.
MergelRijk is a subterranean exhibition located within a former marl quarry in Valkenburg aan de Geul. The site features intricate sculptures carved directly into the soft limestone walls by professional artists. Visitors explore displays that chronicle the geological history of the region, including preserved fossils from the prehistoric Cretaceous sea. A significant portion of the exhibits focuses on the cultural and architectural heritage of Dutch marl stone usage. Interactive elements allow visitors to attempt their own stone carving during the tour. The underground environment maintains a constant natural temperature throughout the year. The facility provides educational insights into both local mining history and artistic techniques. Displays are updated periodically to feature thematic exhibitions related to historical events or pop culture.
The central exhibition hall featuring the large-scale, backlit marl stone carvings.
Bring a light sweater or jacket as the temperature inside the cave remains cool even during hot summer days.
Wear comfortable, sturdy walking shoes with good grip, as the cave floors can be slightly uneven.
Check the official website before visiting, as certain areas are occasionally closed for the installation of new art exhibits.
Assuming the cave is wheelchair accessible throughout; while parts are accessible, some sections have terrain limitations.
Closed on certain mid-week days during the low season; check the official calendar before arrival.
Do not touch the delicate carvings or the cave walls, as oils from human skin can cause damage to the limestone surface.
