6. Wind Cave National Park – South Dakota
While perhaps its most distinctive feature are the strong winds that rush in and out of its mouth causing a loud whistling noise, this cave has so much more to offer.
From the 130 plus miles of explored passages, to the world’s best collection of box work and a calcite formation resembling irregular honeycombs, this cave is sure to impress.
Explore the cave on a number of guided tours, including the Garden of Eden Tour ($10 adults, $5 ages 6-16, free under six) that offers a glimpse of cave formations like the famous boxwork, flowstone and cave popcorn.
Those looking for more of an adventure will enjoy the Wild Cave Tour ($30, ages 16 and up only), which will have you crawling and squeezing your way through some of the cave’s less developed areas.