HUNTINGDON - The 6.8 billion people who live on Earth - a ball with a diameter of 7,900 miles - scurry around on the surface, rarely going up or down very far.
Airplanes and hot-air balloons allow for upward exceptions and submarines and SCUBA gear for downward ones in watery areas.
Likewise coal mines on land.
Mirror photo by Patrick Waksmunski
Lincoln Caverns tour guide Teresa Rader portrays Myron Dunlavy Sr., grandfather of the current owner, as part of the attractions’s sixth annual Discovery Days. This year’s event marks the 80th year since the cavern’s discovery.
People in our area got a special invitation to experience this more natural exception to our stick-to-the-surface habits over the weekend at Lincoln Caverns near here.
The sixth annual Discovery Days celebrated the 80th anniversary of the cave's discovery by workers building current Route 22 west of town.
With tour guides impersonating figures important in the cave's history, it also highlighted the cave's connection with the Dunlavy family, which took over management in 1932 and ownership in 1937.
Ann Dunlavy, granddaughter of the Buffalo, N.Y., man who bought the cave from original developer Harry Stewart - the farmer who owned the land - has managed it since 1977 and is now president.
Lincoln Caverns is one of nine "show caves" in Pennsylvania, among 1,000 that are mapped and 50,000 mapped caves nationwide, according to a history provided by Dunlavy.
A cave is a cave if you can enter it far enough to be out of range of all natural light, she said.
A tour guide Sunday showed groups what that meant by extinguishing the lights in a small room - although they weren't off long enough to rid this reporter's mental view of residual light.
Another guide also turned off the lights in another room to show visitors the dim phosphorescense from a "flowstone" formation.
There were stalagmites (the word has a "g," and it builds from the ground, a guide said helpfully); stalactites (the word has a "c," so it hangs from the ceiling); frozen waterfalls, a formation called "bacon," for it's resemblance to breakfast meat; and horizontal ridges indicating groundwater levels that were once much higher.
There were slender root tendrils from trees 30 feet overhead on the wooded hillside and lots of small cavities extending into darkness off main passages.
The property actually offers tours of two caves - the original Lincoln Caverns and a second unconnected set of caverns called Whisper Rocks discovered in 1941 through a sinkhole and developed in 1961 by Dunlavy's father.
"They're cool," said Brian James of Baltimore, after his tour.
He meant figuratively, but could have meant literally: It was about 52 degrees inside.
"Natural air conditioning," he said.
The cave formed over millions of years as limestone formed from shells deposited on an ancient seabed then lifted up to form the Allegheny Mountains was dissolved by rainwater that had turned acidic from percolating through soil above, according to a guide.
The formations occurred as more water with dissolved limestone drips and evaporates, leaving tiny deposits.
It takes 100 years to add an inch to the formations, a guide said.
One cautioned visitors not to touch the formations, because skin oil left behind sheds water drops too quickly, inhibiting those tiny deposits and the continued development of the cave.
Dunlavy prides herself on helping undo old prejudices against commercial cave development by exercising environmental sensitivity and through education.
Sixty percent of her business is comprised of school and Scout tours, she said.
She's trying to help get the word out on white nose syndrome, a scourge that has decimated the population of cave bats in the Northeast.
She's also an advocate for ending the practice of dumping rubbish in sinkholes, because those are access-ways to the "Swiss-cheese" karst formations that underlie 20 percent of the U.S.
They're also access-ways to sometimes-distant groundwater, which provides 50 percent of the U.S. population with drinking water, she said.
In developing Whisper Rocks, the family kept virtually everything natural - other than creating a practical entrance, installing lights, laying gravel on the walkways and removing one unstable rock, she said.
By contrast, there are several stone walls and even large steel beams in Lincoln Caverns, plus lots of steps and handrails and evidence of earlier guides tapping formations to demonstrate their characteristics for visitors.
Ryan Scaife of Baltimore, in whose recent wedding James was best man, feared he would be claustrophobic underground.
But other than feeling "a little weird," he was OK.
James' friend Danielle Griefzu of Baltimore was impressed by learning that the caves had been filled with water once.
"And now it's gone," she said.
"Caves are non-renewable natural resources - irreplaceable and priceless features of our American landscape," Dunlavy's history states.
People don't think about what's underground nearly enough, Dunlavy said.