The stereotypes we have about caves are mostly based on caves that have erosion and redeposition of limestone. The Lascaux and Les Frieres caves with the prehistoric art are of that sort.
Lava Tube caves are quite different, but may have art in them also. They are dry and cool in temperature, which preserves artifacts. They’re a museum conservator’s happy dream. One of the reasons the art survives, in darkness, is that the air is a constant 50-something degrees F from the temperature of the ground itself in the bigger systems. Lava Beds caves run about 55 degrees F, there is a Wiki note on Mammoth Cave that it runs about 52 degrees, and the humidity tends to remain constant. There are also ice caves (as in the Lava Beds system) where the cave picks up more ice in the winter than it dissolves in the warm summer air filtering in from outside, so it generally stays cold enough that remains of animals that fell into it, or were tossed in as leftovers by people, can be frozen for thousands of years.
Mammoth Cave is probably the most famous, and it is certainly single biggest limestone system.
https://en.wikipedia.org/wiki/Mammoth_Cave_National_Park
Thousands of miles of passages, and more to come as they explore more. They’re still finding stuff. Tey have to do it carefully, as much for possible archaeological finds as for safety.
As Wiki notes:
Mammoth Cave National Park is a U.S. National Park in central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. The official name of the system is the Mammoth Cave System for the ridge under which the cave has formed. The park was established as a national park on July 1, 1941. It became a World Heritage Site on October 27, 1981, and an international Biosphere Reserve on September 26, 1990.
The park’s 52,830 acres (214 km²) are located primarily in Edmonson County, Kentucky, with small areas extending eastward into Hart County and Barren County. It is centered around the Green River, with a tributary, the Nolin River, feeding into the Green just inside the park. The Green River is dammed near the western boundary of the park, so that the river only flows freely for a small section in the eastern part of the park…
…The park’s tours are notable for the quality of the interpretive program, with occasional graphics accompanying artifacts on display at certain points in the cave. The lectures delivered by the National Park Service cave guides are varied by tour, so that in taking several tours the visitor learns about different facets of the cave’s formation, or of the cave’s human history and prehistory. Most guides are quite knowledgeable and open to visitor’s questions. Many guides include a “theatrical” component, making their presentations entertaining with gentle humor. The guide traditions at Mammoth Cave date back to the period just after the War of 1812, and to guides such as Stephen Bishop. The style of this humor itself is part of the living tradition of the cave guides, and is duly a part of the interpretive program…
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Bishop, by the way, was a famous guide and is credited with the first extensive accurate maps of the system, although he was a slave all his life. When the cave was sold to someone who turned it into a turberculosis clinic, that is what eventually killed him.
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…Research beginning in the late 1950s led by Patty Jo Watson of Washington University in St. Louis, Missouri has done much to illuminate the lives of the late Archaic and early Woodland peoples who explored and exploited caves in the region. Preserved by the constant cave environment, dietary evidence yielded carbon dates enabling Watson and others to determine the age of the specimens, and an analysis of their content, also pioneered by Watson, allows determination of the relative content of plant and meat in the diet of either culture over a period spanning several thousand years. This analysis indicates a timed transition from a hunter-gatherer culture to plant domestication and agriculture.
Another technique employed in archaeological research at Mammoth Cave was “experimental archaeology”, in which modern explorers were sent into the cave using the same technology as that employed by the ancient cultures whose leftover implements lie discarded in many parts of the cave. The goal was to gain insight into the problems faced by the ancient people who explored the cave, by placing the researchers in a similar physical situation.
Ancient human remains and artifacts within the caves are protected by various federal and state laws. One of the most basic facts to be determined about a newly discovered artifact is its precise location and situation. Even slightly moving a prehistoric artifact contaminates it from a research perspective. Explorers are properly trained not to disturb archaeological evidence, and some areas of the cave remain out-of-bounds for even seasoned explorers, unless the subject of the trip is archaeological research on that area…
…In partnership with Valentine Simon, various other individuals would own the land through the War of 1812, when Mammoth Cave’s saltpeter reserves became significant due to the British blockade of United States‘s ports. The blockade starved the American military of saltpeter and therefore gunpowder. As a result, the domestic price of saltpeter rose and production based on nitrates extracted from caves such as Mammoth Cave became more lucrative.
In July 1812, the cave was purchased from Simon and other owners by Charles Wilkins and an investor from Philadelphia named Hyman Gratz. Soon the cave was being mined for calcium nitrate on an industrial scale….
In related links:
https://en.wikipedia.org/wiki/Colossal_Cavern
…Colossal Cavern is a cave in Kentucky, USA, the main entrance of which is at the foot of a steep hill beyond Eaton Valley, and 14 m from Mammoth Cave. It is connected with what has long been known as the Bedquilt Cave. Several entrances found by local explorers were rough and difficult. They were closed when the property was bought in 1896 by the Louisville & Nashville railway and a new approach made. From the surface to the floor is 240 ft. under Chester Sandstone and in the St Louis Limestone.
Fossil corals fix the geological age of the rock. The temperature is uniformly 54 F, and the atmosphere is optically and chemically pure. Lovely incrustations alternate with queer and grotesque figures. There are exquisite gypsum rosettes and intricately involved helictites.
Bedquilt, not Colossal, was also the inspiration and setting for the first truly interactive computer game. Co-written by Will Crowther, a caver who spent many hours helping to survey the cave and appropriately called “Colossal Cave”, the computer game became the inspiration for the classic game Adventure…