The Marengo Cave National Landmark is the most famous natural attraction of the state and has been open to the public since its discovery in 1883 by 15-year-old Blanche Hiestand and her 11-year-old brother Orris. One of the best ways to explore the cave and surrounding areas is by taking one or both of walking tours offered at the site. The Crystal Palace tour takes forty minutes to complete, is great for beginners, and introduces visitors to different cave formations. The slightly more challenging Dripstone Trail takes about 70 minutes to complete but introduces visitors to a wider range of fascinating cave formations like soda straws and Marengo Cave?s famous Penny Ceiling.

For a more intense adventure, the place also offers the 2-hour Underground Adventure tour ? a trip that also educates visitors on cave conservation ? as well as the Weekend Underground Adventure. Last but not the least is the Waterfall Crawl, which allows visitors to explore the tenth largest underground spring in the state.

Other activities available at the area include camping, souvenir shopping, gemstone mining, and canoeing.