Come and see the natural beauty of Niagara Cave. Nationally recognized as one of the Top Ten Caves in the United States. On our 1-hour guided tour: Hike one mile underground to depths of 200ft. Discover fossils ~ 450 million years old. See cave formations both delicate and massive. 60ft. Waterfall, wedding chapel, stalactities. Temperature is 48 degrees. Walking shoes are also recommended. Also enjoy: Miniature golf, concessions, gemstone mining, picnic grounds, unique gifts. Open April – October. Located 2 miles south of Harmony, MN on Hwy 139, then two miles west on County Road 30. Just 1 mile north of the Minnesota/Iowa border on Hwy 139 – then west.