The Wind Cave National Park at Custer State Park in South Dakota is one of the world's longest caves. Established in 1903, this national park covers 28,295 acres of grasslands to the pine forests in the Black Hills.
The wind cave is true to its name because of the strong gusts that rush in and out of the cave's mouth, "equalizing air pressure between the passages inside and the atmosphere outside," says National Geographic Guide to the National Parks of the United States.
The American buffalo or bison, pronghorn mule deer and prairie dogs are easy to spot. According to the National Geographic, you'll hear the haunting bugling of elk as well as see wild turkeys, meadowlarks, nuthatches and prairie falcons.
There are 104 miles of caves below the surface, though these aren't the "usual" types of caves. Because of dryness, there are no stalagmite and stalactite formations. Instead, there are mineral formations called boxwork, "a calcite formation resembling irregular honeycombs," says National Geographic.
First-time visitors will most likely choose either the Natural Entrance tour (one hour, 15 minutes) or the Fairgrounds tour (one hour, 30 minutes). Both tours feature the Blue Grotto, the Devil's Lookout and the Post Office, which shows off the boxwork (it looks like brown bats holding hands.)
The park and visitors center is open all year except Thanksgiving, Christmas and New Year's Day. Late September to May is considered off-season, when there aren't as many tours.
Claustrophobic visitors may want to avoid the caves and instead should hike, explore wildlife and tour the gift shop (all above ground). Also, the shortest climb is 150 steps, so people with physical limitations may want to reconsider.
