All of this survived, in some cases with extraordinary preservation, because the cave environment does not allow organic material to decay in the way that outdoor environments do.

The dry passages of Mammoth Cave are, in the most literal sense, a time capsule.

The contents of that capsule have been accumulating for thousands of years, and archaeologists have been reading it, carefully, since the 1960s.

Five Thousand Years Of Human Presence

The National Park Service dates the beginning of human exploration of Mammoth Cave to between 5,000 and 4,000 years ago — roughly 3000 to 2000 BCE by the calendar.

This is when the first unambiguous archaeological evidence of people inside the cave appears: the charred fragments of river cane torches, the distinctive scrape marks of mussel shells on mineral-bearing walls, the artifacts and food remains that tell archaeologists someone was here.