National Parks

Wind Cave National Park

Location: Southwestern South Dakota

Known for: Having one of the largest caves in the world, with approximately 95 percent of the world's known boxwork formations (3-D calcite honeycomb patterns on cave walls and ceilings).

Biggest crowds: Early August

Accessibility: You can easily view the beautiful Black Hills and the grassland prairie, but to get the park's full effect, you'll need to head into the caves.

Why kids like it: Exploring underground caves!

What hikers say: There's great hiking here—both above and below ground.