The basics: The maze of passages known as Wind Cave stretches deep beneath rolling prairie in western South Dakota. The expansive cave, a focal point of this park, holds geological wonders. Among them is boxwork, a strange web of calcite that is unusual in most caves but abundant here. Wind moves in and out of a small natural opening that is not far from the visitor center. It has long been a sacred place for American Indian tribes.
Visitors: 612,198 people visited the park in 2015.
Square miles: 53.
Established: 1903.
More information: nps.gov/wica; 1-605-745-4600.
