Guided tour of Bonsdal quarry

This unique place offers a raw look at the past. Perfect for lovers of history, nature and places with character.

Marl evolution
The tour starts at the old Curfs lime kiln. The guide talks about marl, the soft, yellow rock formed millions of years ago at the bottom of a tropical sea. You will discover how marl was used in agriculture and construction for centuries, and how its extraction evolved from open quarries to a network of underground passages.

Rich history
The quarry also houses a lesser-known chapter from World War II. Under the code name Operation Molch, 2,500 forced labourers set up an underground workshop here to overhaul BMW 801 aircraft engines. Traces of that period are still visible, such as old rails and technical installations. After the war, the quarry was given new functions, as a shelter and mushroom farm. Today it is a protected nature reserve, managed by Het Limburgs Landschap.

There are two options for this tour:

• The standard guided tour (1 hour and 10 minutes), focusing on the story from World War II.
• The extensive guided tour (2 hours), which starts outside at the lime kilns and also offers a brief look into the tunnel towards the Curfs quarry.

Book your tickets via the website and thereby support the preservation of this unique piece of heritage.