Atlas Obscura is organizing trips! Join us on an adventure »
Today Only: 50% off Atlas Obscura books and calendars at Barnes & Noble »

Maastricht, Netherlands

St. Pietersberg Caves

Incredible labyrinth of man made caves. 

Ancient limestone quarry tunnels are decorated with generations of graffiti. During WWII the tunnels were converted for use as an air raid shelter, but were never used. Fossils of a prehistoric Mosasaurus and turtle discovered here are now on display at the Maastricht Natural History Museum.

One tour per day in English.