Municipal caves

Gemeentegrot Valkenburg is an ancient underground cave network beneath the historic town of Valkenburg in the Netherlands, comprising over 110 hectares of tunnels carved from marlstone over centuries. Guided tours — available on foot or aboard a narrow-gauge train — explore the labyrinthine passages and reveal layers of history: wartime shelters used during World War II and the Cold War, medieval wall carvings, and a dedicated Cycling History Gallery (Wielergalerij) celebrating the cave's role as a legendary winter training venue for professional cyclists. The constant temperature inside is 12°C; a warm layer is recommended.