Some 350 bison roam the prairie's above Wind Cave, and this small herd greeted us as we drove in...

We didn't get to explore the above ground portion of the park (over 28,000 acres) but through the windows of our bus...here, the high plains meet the forested Black Hills providing for a wide variety of flora and fauna...

The beautiful arch bridge over Beaver Creek Canyon...

A moving shot of the park entrance sign...

From 1934-39 the CCC built many of the structures you see in the National Park, including the visitor center...

Heading in...

A pre-National Park Visitor Log Book from July 5th, 1893...Wind Cave was run as a private attraction until becoming the country's 7th National Park in 1903...

Differences in pressure in and outside the cave create the namesake 'wind' at the cave entrance...today air was rushing out of the cave at 23 mph but I read that on rare days it can blow at over 60!!

There are over 130 miles of cave passages that have been explored to date...all under only 1 square mile of ground!!

This tiny opening is the natural entrance to Wind Cave, where explorers originally entered...I must admit, even with previous knowledge, it was strange feeling a 23 mph whooshing out of the ground...

After passing through pressure-equalizing doors, we started the descent...

Watch your head!