Spelunk: Explore Caves as a hobby.
Even if you don't want to delves deep into the unknown abyss of the underground network of the mystery of South Dakota's vast cave systems, wired with ropes and helmets, you can venture into Jewel Cave National Monument and Wind Cave National Park on a guided, safe and illuminating cave tour.
In Murder in Custer State Park, Merritt and Josh explore Jewel Cave on a Ranger Tour and hike above ground on the Hell's Canyon Trail.
Jewel Cave was set aside as a National Monument in 1908. Spelunkers originally believed the cave to be relatively small, until exploration teams in the 1950s discovered the vast mazes of passageways. To date over 168 miles of mapped and surveyed passages, make Jewel Cave the second longest cave in America (behind Mammoth in KY) and the third longest cave in the world!
The cave was named by Frank and Albert Michaud, two area prospectors, who discovered the cave in 1900. They thought the calcite formations resembled 'jewels.' Jewel Cave is an adventure both above and below the earth. The National Park Service offers several cave tours, including the basic 'Discovery Tour,' popular 'Lantern Tour,' and even 'Spelunking Adventures.' Reservations are recommended for the tours. Scientists and spelunkers are constantly searching for new passageways and mapping new discoveries into their search of the cave's unknown spots. Cave life is surprisingly complex, with an ecosystem based on limited sunlight, bats to small bugs...Even in the depths of darkness there is life...
"Jewel Cave was formed by the gradual dissolution of limestone by stagnant, acid-rich water. The water enlarged a network of cracks that had formed during the uplift of the Black Hills approximately 60 million years ago. The layer of calcite crystals that covers much of the cave walls was created by the re-deposition of calcite from water saturated with the mineral.
After the water that formed the cave drained, speleothems (cave formations) began to form. Jewel Cave contains all the common types of calcite formations, such as stalactites, stalagmites, flowstone, and frostwork, although not in the same abundance as other well-known caves. The dry parts of the cave contain some formations created by the deposition of gypsum, such as gypsum needles, beards, flowers, and spiders. Finally, Jewel Cave contains a very rare formation called a hydromagnesite balloon. Those are created when gas of an unknown source inflates a pasty substance formed by the precipitation of the magnesium carbonate hydroxide mineral." - from park website.
I recommend doing The Lantern Tour and taking time to hike Hell's Canyon - bring plenty of water as the prairie heat can be scorching.
For more information about Jewel Cave:
Wind Cave National Park:
Just south of Custer State Park, is a sprawling undaunted prairie, where tall grasses wave in the rhythm of the wind and bison roam, and prairie dogs bark. If this tapestry of wind and grassland wasn't enough to inspire, below, hidden in the vault of the earth is Wind Cave. Wind Cave is one of the oldest caves in the world, forming 320 million years ago from erosion, sediment deposits, cracks and dissolution. Wind Cave is a magical wonderland. It is known for its exquisite intricate boxwork formations- thin, honeycomb shaped structures of calcite that protrude from the walls and ceilings. Wind Cave has a few stalactites and stalagmites, what makes this cave unique is the diversity of features and complex geology of the cave. It is amazing to note that in 100 years of modern cave's exploration (it was known as a sacred place to American Indians prior to rediscovery), has only reveals 5% of the caves network of passageways (determined by barometric wind studies). Scientists and spelunkers continue to defy the dark and delve into the recesses of the cave charting bit by bit new discoveries of this ancient underworld of art.
While at Wind Cave take time to do a cave tour or two, each tour offers a slightly different look at various cave features. Enjoy a prairie hike and work on spotting prairie dogs and bison.
For more information:
Wind Cave: http://www.nps.com/wica