Swaying prairie grasses, forested hillsides, and an array of wildlife
such as bison, elk, and prairie dogs . This is one of our
country’s oldest national parks and one of its few remaining intact
prairies. Secreted beneath is one of the world’s longest caves, Wind
Cave. Named for barometric winds at its entrance, this complex labyrinth
of passages contains a unique formation of crystals called boxwork. We took an elevator down 22 stories and then were lead trough the caves on a 1 1/2 hour tour.  It was very difficult to take any good pictures on our iphones.