During September, Mammoth Cave will celebrate the 40th anniversary of the discovery of its connection to the Flint Ridge cave system.
On Sept. 9, 1972, a passageway was found linking the two cave systems. Explorers knew they were onto something when they saw a handrail, meaning they had hit the developed section of Mammoth Cave.
That would tip you off, all right.
Roger Bruckers book The Longest Cave describes the discovery in more dramatic terms: John stood stunned. The walls had opened out. He had come into a tremendous void, with a lake ahead. He could hardly sense a wall anywhere, but there was one in the distance, straight ahead. Slowly his eyes became accustomed to the gloom. What was that gleaming, horizontal line against the far wall? Surely it was a pipe! Yes, a handrail! With vertical supports!
The discovery made Mammoth Cave by far the worlds longest known cave, with more than 392 miles of interconnected passages.
Mammoth Cave, northeast of Bowling Green, is a sight every Kentuckian should see, especially the natural splendor in the caves Broadway area.
Officially the cave was discovered by European explorers at the end of the 19th century and was lit by grease-oil lamps for more than a century. Its 192-foot-tall Mammoth Dome and 105-foot-deep Bottomless Pit make it something like a Grand Canyon of the underworld.
The cave saw a dip in annual visitors about 2006 to 347,357, about half from the parks peak in 1973 but has since rebounded. The National Park Service saw a similar decline in visitors to parks across the nation at that time. Vickie Carson, Mammoth Caves public information officer, said the visitor numbers picked up after that and now run right around 400,000 a year.
Between 500,000 and 600,000 people a year visit Mammoth Cave National Park.
Why doesnt everyone who visits take a tour? The tours are reasonably priced $5 to $48 for adults, less for children and students and not particularly strenuous: The shortest tour is 75 minutes, the longest six hours.
Not everyone is a natural spelunker, however. The caves soaring spaces are countered with areas that might be uncomfortably tight or low.
I remember walking down into the big mouth of the cave with a visitor, Carson said. He just stopped, midway down the steps, and said, I cant go in there. Sometimes you dont know until youre there.
For those who are wary of caves or just want a more thorough visit, Mammoth Cave will open in October the second phase of its new visitors center, with more exhibit space.
Other tips: Summer is the caves biggest season, and probably the one in which its consistent interior temperature in the 50s feels the best. But if you want a smaller tour and more individual attention, Carson advises touring when schools are in session: weekdays in fall and spring.
Its really such an alien space, so hard to grasp, she said, that it really was an underground river, that youre inside a hill for the prehistoric people who came to the cave.