Wind Cave is the third largest cave in the World with more than 200km of explored tunnels! It is located in the Black Mountains in South Dakota and preserved as a National Park.
It is not only the cave, but the above-ground world is also nice: prairies with prairie dogs, bison, etc. Not bad, really.
The cave was discovered around 1880 when two brothers found a hole in the ground from which wind came out. Some early explorers adventured into this hole with candles and ropes tied in their ankles to see what it was, and they found a huge cave.
This is Devil's Pass,a crack which is as high as a 4-floor building!
Wind Cave is famous for two structures in its walls:
2. Pop Corn
These two structures are created through two different geological processes. Explanation here.
Some more boxwork:
And the enjoyable prairies once again.