Much of Minnesota’s bedrock is limestone. This makes an excellent foundation for the development of caves. Niagra Cave in Harmony, Minnesota, is just such a cave.
The tour will take you 200 feet below the surface. Along the way, you will see various cave formations and fossils. Heads up, however. You can expect to climb 275 stairs as you see an underground waterfall and makeshift wedding chapel.
Niagra Cave is a family-run business with many tourist-type gifts, including fossils, rocks, and crystals. You can even pan for gems.