Wind Cave National Park, June 17-19

Wind Cave National Park is just south of Custer State Park.  In fact, I inadvertently took a gravel road into Wind Cave NP off of the State Park's Wildlife Loop Road one day.  Wind Cave's claim to fame are rare cave decorations called "box work."  It kind of reminds me of lace hanging down from the ceiling (pic: http://www.nps.gov/mwr/customcf/apps/CMS_HandF/Pictures/WICA_Boxwork-for-DYK.jpg).  It also has some beautiful frostwork that look like suspended sparkly white snowflakes in the light (pic: http://www.nps.gov/wica/naturescience/images/Frostwork-35.jpg).

Wind Cave is the 4th longest cave in the world.  Because of all of the rain that this area has been having lately, this normally dry cave was dripping wet when I visited it.  One amazing fact about this 134-mile-long cave is that it is below only a 1 square mile surface area above ground.  Another amazing fact is that this cave breathes.  When the barometric pressure is high (rainy days), the cave breathes in.  And when the barometric pressure is low (sunny days), the cave breathes out.  You can feel its "breath" as wind when you are in the cave.  The wind was measured to be over 75 MPH at one time.  When I was there, you could barely feel a gentle breeze as it was breathing in.