In a labyrinth that once comprised more than 20,000 corridors, an experienced guide takes you underground to see the names and drawings of people who worked here every day a few hundred years ago. Did you know that with a capacity of 50,000 people,, the expansice cave network was able to provide shelter for many of Maastricht’s residents during the Second World War. An evacuation area with electric lighting, a public address system, a bakery, toilets, chapels, a small hospital, water pumps, and many more facilities were all constructed underground, though never put into full use. Remnants of them can still be seen.