Original photo by Posnov/ Moment via Getty Images
On September 9, 1972, spelunkers exploring Kentucky’s Mammoth Cave system made an incredible discovery. While plumbing the darkest recesses of the nearby Flint Ridge Cave system, then the longest known cave in the world, the group suddenly spotted a well-groomed tourist trail that belonged to Mammoth Cave. The spelunkers quickly realized that the two cave systems were actually one, making Mammoth Cave the longest cave in the world. (The world’s second-longest cave, Sistema Ox Bel Ha in Quintana Roo, Mexico, is around 150 miles shorter.) With the discovery, what was once simply one of America’s oldest tourist attractions became one of the world’s grandest caves.
Oops, incorrect!
It's a fibVirginia’s General Assembly created the county of Kentucky in 1776, and the county (which eventually split into smaller counties) remained a part of the state until 1792, when Virginia ceded it to the newly formed United States. Kentucky became the 15th state that same year.
This historic revelation was the culmination of thousands of years of human exploration of the cave system. The first peoples to enter the cave were Native Americans, who explored roughly 19 miles of its interior some 5,000 years ago. Tribes used the cave for shelter, and the discovery of mummified remains suggests they also found the caves sacred in some way. In the years leading up to the U.S. Civil War, an enslaved cave guide named Stephen Bishop extended the cave’s known length while also creating its first map. Entire families of explorers traversed the caves leading up to the 1930s, until Mammoth Cave became a national park in 1941. With around half a million visitors every year, Mammoth Cave continues to inspire awe just as it did many thousands of years ago.
Numbers Don't Lie
More Interesting Reads
The most-visited national park in the U.S. is ______.
Ready to reveal?
Confirm your email to play the next question?
The most-visited national park in the U.S. is the Great Smoky Mountains.
The world’s largest cave has its own weather system.
In Vietnam’s Phong Nha-Ke Bang National Park lies Hang Son Doong — the largest cave in the world. While the cave was discovered by a local in 1990, it took almost two decades for an official expedition to rediscover it and explore its vast interior, which encompasses a dumbfounding 1.35 billion cubic feet. Because of the cave’s immense size and consistent year-round temperature (a very comfortable 73 degrees Fahrenheit), when warm air enters the cave it forms clouds, which then cool and produce rain inside the cave, creating a unique rainforest ecosystem. This occurs at the cave’s mouth and at two dolines, spots where the cave ceiling collapsed around a millennia ago. These cave clouds only form in Vietnam’s warm and muggy spring, summer, and fall months. During the winter, when outside temperatures are cooler than the cave’s ever-consistent 73 degrees, the weather inside Hang Son Doong is crystal clear, much like in many other much smaller caves on the planet.
Darren Orf lives in Portland, has a cat, and writes about all things science and climate. You can find his previous work at Popular Mechanics, Inverse, Gizmodo, and Paste, among others.
