Discovered in 1937, Mystery Cave is the longest cave in Minnesota – spanning over 13 miles underground. It is a network of passages that was dissolved by moving water where visitors can see stalactites, stalagmites, flowstone, and beautiful underground pools. Mystery Cave is located in Forestville/Mystery Cave State Park. Visitors can explore the William H. Morrissey Visitor Center to learn about the Driftless Area and Mystery Cave. A variety of guided tours are offered daily in the summer and include modern lighting and paved walkways that enhance accessibility to more rustic lantern and wild cave tours.