Maastricht - St. Pietersberg Caves

St. Pietersberg Caves are wonderful to explore and are situated to the south side of Maastricht. It is a wide ramified system of passages and tunnels which were formed many centuries ago by the local marlstone quarry and it even provided shelter for the inhabitants during the sieges of town. Originally, there were 20,000 or so passages with a length of 200 kilometers. During the Second World War, some of these passages were enlarged and a well was also dug.