The Caves of St. Pietersberg are a network of underground tunnels located near Maastricht, in the Netherlands. These caves were formed from the extraction of limestone and stretch over 200 kilometers. They have a rich history, dating back to Roman times, and were used for various purposes, including as a refuge during wars. Today, the caves are a popular tourist attraction, offering guided tours that showcase their unique geological formations and historical significance. Visitors can explore the fascinating underground passages, learn about the cave's history, and see remnants of past activities, such as mining and storage.