Forestville Mystery Cave
With over 13 miles of passages this is the longest cave in Minnesota. It was discovered in 1937 although the passages were formed by trickling water about a million years ago. The cave is a spectacular natural phenomenon but it's not the only attraction in the park. There is also Forestville Village which was restored to its 19th-century appearance and is now a living history museum. Bring a jacket for the cave - it stays a chilly 48 degrees Fahrenheit year round.