Mammoth Cave is the longest recorded cave system in the world, with more than 336 miles (541 kilometres) explored and mapped. It is some 127 yards (116 metres) deep and has five layers of caves descending into the depths.

What Lies Beneath

About 350 million years ago the area was beneath a shallow sea. As time passed the waters receded, leaving behind layers of sandstone over limestone. Underground rivers, whirlpools and streams cut passages and caverns out of the rock, creating the enormous system of caves.

What remained when the first visitors came to the caves, approximately 14,000 years ago, were hundreds of miles of caves - only a third of which, perhaps, have been mapped and explored to this day. The mostly dry caves became home to more than 200 different types of cave fauna, including bats, fish, salamanders, woodrats, crayfish, springtails¹ and crickets. It is also home to more than 40 types of lichen. Being dry, the cave lacks the rock formations that people generally associate with underground caverns, like stalagmites and stalactites.

Discovery of the Caves

The first known humans to pass through the region of the Mammoth Cave were PaleoIndians (living between 12,000 and 8,000 BC). The PaleoIndians were nomadic people, following the herds of bison and mastodons that were their primary source of food, so their movements and settlements across America have been hard to pin down. However, several PaleoIndian spear tips have been discovered around the caves.

The glacier-bound conditions that had forced the PaleoIndians into a nomadic existence receded somewhat during the Archaic era (8,000 - 1,000 BC) and during this time Archaic Indians began to settle much smaller territories. Hunting smaller animals - like deer and turkeys - and gathering berries, nuts and vegetables, the Archaic Indians established settlements as competition for resource grew from rival bands.

The Archaic Indians activities within the caves have evaded complete understanding by anthropologists and archaeologists, although they suggest that the Indians may have been collecting selenite, mirabilite, epsomite and gypsum. The reasons for this, however, are also unclear, although the materials may have been used for trading or utilised ceremonially or medicinally.

During the next couple of thousand years, the Indians used the materials from the caves for trade, while hunting, farming and building their homes on the surface.

However, the arrival of European settlers pushed the Indians from their established territories and the use of the caves became less frequent. The caves were 'discovered' by Europeans settlers in the late-18th Century, but were given the name 'Mammoth Cave' in 1812. The cave system is rich in sodium nitrate, or saltpetre, which was mined for use in the manufacture of gunpowder during the War of 1812.

The National Park

With the end of the war and the demand for saltpetre, the caves became a source of intrigue and invited investigation from ordinary folk. From 1816 onwards, the caves were a tourist attraction that gathered attention by word of mouth and by the publicised journal entries of those who visited them. The area not only offered the caves to draw tourists, but also a huge area of natural beauty, thick with rugged forests and fish-laden rivers.

During the 20th Century, the caves' draw for tourists continued, and on 1 July, 1941 the Mammoth Cave officially became a National Park.

One notable attraction of the time was when the desiccated body of an Indian was discovered in the caves in the mid-1930s. The pre-Columbian Indian was found beneath a large rock, which had most likely been the cause of his death. The body was incredibly well preserved, due to the presence of sodium nitrate in the sand bed around it. After it was discovered and moved, the body started to deteriorate, but careful storage conditions created by museum experts stemmed the rapid decay of the find.

The Caves Today

The Mammoth Cave was recognised as a World Heritage Site on 27 October, 1981, and was designated as an International Biosphere Reserve on 26 September, 1990.

For anyone who is hitchhiking through this area, or has an interest in caves, the Mammoth Cave is certainly worth investigating. Admission to the national park is free. A fee is charged for camping and cave tours. While the fee charged is quite reasonable, the crowds at the park usually aren't.

Guided tours are available for most of the year, from mid-Spring to early-Winter. These include the simplest Discovery Tour, which takes in the larger trunk passages, and is available either as a self-guided or ranger-guided tour (the latter being slightly more expensive). The mid-range activities include an Introduction to Caving session, that lasts three hours and teaches safe caving techniques, suitable for anyone from age ten upwards. The top of the scale is the Wild Cave Tour, which lasts six hours and takes in more than five miles (eight kilometres) of caving, requiring basic caving equipment. The Tour includes free-climbing, working through tight crawlways, squeezing through openings as tight as nine inches (twenty centimetres), and crawling through rock and dirt - and is only available to adult cavers.

There are things to interest visitors beyond the caves, on the surface, including hiking trails, campgrounds, canoeing and horseback riding. For those who don't savour the prospect of camping, there are more permanent and solid accommodations available near the Park. Indeed, the Mammoth Cave Hotel, sited in the Park itself, has been around for almost as long as tourists have been coming to the cave.