Wafer-thin sheets of rust-colored rock hang in rows from the ceiling, like feathers on an ancient wing. Sheets of petrified calcite seem to fold and drape along the cool cave walls.

This is “boxwork” and “cratework,” two of the rare rock formations that make Wind Cave National Park so special.

The park extends across and beneath more than 28,000 acres of pine forest and grassland. Above ground, you can wander trails cut through the ponderosa and prairie. Stop to listen for the movement of bison, mule deer, and prairie dogs.

Below the surface lies a mystifying labyrinth of tunnels that have fascinated geologists since they were discovered in 1881. To date, spelunkers have ventured 132 miles into the earth, making Wind Cave the fourth longest in the world. And still, much of it remains unmapped.

Visit one of the oldest national parks and the first created to protect an underground resource. At Wind Cave National Park, you’ll discover how the caves were formed, what geologists have learned from them, and how you can support efforts to preserve them.

Source

• http://www.npca.org/parks/wind-cave-national-park.html