Mammoth Cave
Hole in the Ground
The caves in Mammoth Cave National Park are carved mostly out of limestone, a soft rock formed from the shells and remains of tiny sea creatures that settled here when this whole area was covered by a shallow ocean hundreds of millions of years ago. Over time, slightly acidic rainwater seeped into cracks in the limestone and slowly dissolved it, widening those little gaps into the miles of winding passages that make up the cave today. A tougher layer of sandstone sits on top in many places, acting like a natural roof that helped protect the cave and let it grow into the enormous underground world visitors explore now.
Above ground, Mammoth Cave National Park stretches across about 52,000 acres of forest, quiet rivers, and those gentle rolling Kentucky hills that seem made for wandering. More than 80 miles of hiking trails snake through the woods, along limestone ridges, and down to the banks of the Green River, with everything from easy strolls to longer backcountry rambles where you might not see another soul for a while. The park is also recognized as a UNESCO World Heritage Siteand an International Biosphere Reserve, which is just the world’s fancy way of saying this place above ground is every bit as special as the miles and miles of cave hidden underneath it.
