Gemeentegrot Valkenburg

South Limburg sits on marl, a soft limestone that can be sawn by hand into building blocks, and it has been cut out of the hillsides here since the Roman period - the resulting quarries are not natural caves but a network of man-made galleries running for many kilometres under Valkenburg and the surrounding hills. The Gemeentegrot is the municipal section, open on guided walks, and what is on the walls is the interest: charcoal drawings and inscriptions left by quarrymen over centuries, later sculpture cut into the soft rock, and traces of the periods when the passages were used as refuges - in the Eighty Years War, and again in the Second World War when parts served as shelters and hiding places. Temperature is a constant twelve degrees. Valkenburg above is the most touristed town in Limburg, with a castle ruin and a Christmas market held in the caves.

What you actually see

• Man-made galleries - marl sawn out by hand over centuries, not natural caves.
• Charcoal drawings - quarrymen's marks and inscriptions across the walls.
• Wartime use - the passages as refuges and hiding places, with traces left.
• A constant twelve degrees - the temperature underground all year.

When to go

All year. Half a day.

Honest expectations

Guided tours only, and it is cool underground - take a layer. Valkenburg is heavily commercialised and busy. The Christmas market in the caves is very crowded and ticketed separately.

Nearby

Maastricht is west; the Geul valley and Epen are south-east.