Nestled here in this verdant landscape is Mammoth Cave National Park in the countryside of south central Kentucky.

In the Green River Valley, the park's gentle wilds or spacious with ample room to accommodate visitors in the back country.

Way river with.

Aside from the river, there are a few streams to be seen.

Much of the water here seeps into the earth and is absorbed by a soil of decomposed limestone.

Thus, over eons, water has formed Mammoth Cave.

It is a cave known for its eerie silence.

Light is beamed into a dark underground world that began 10 million years ago, a world of labyrinths and palatial chambers that echo the caves.

History History as fantastical as these ghostly limestone Spector's.

There's evidence that the earliest people to live in this valley some 2000 years being seen prehistoric Native Americans made use of this case.

It was a place of interment.

The remains of their dead have been found, and they're simple.

Reed torches have been found as far as two miles inside the cave.

Yeah, they even mind the Kafer gypsum once more.

There was mining during the War of 18 12.

America needed gunpowder.

Peter Mind from the cave was processed into explosives.

Tours were begun as early as 18 60.

Early visitors left graffiti slaves served as guides.

One of them, a remarkable young man named Stephen Bishop, probe passages that had never before been reached.

He discovered a subterranean river and a mammoth dome.

Heart Visitors can tour this underworld and explore these awesome chambers with the knowledge that this is the longest known cave on our planet were the second and third longest caves joined together.

This would still be the world's longest today.

Scientific cave explorers called spelunkers probe farther and farther into the caves unknown.

It's hard work dropping into the abyss on a thin crawling through tight, tiny passages.

Creatures that live their entire lives in the caves, darkness or examined studied insects and Iraq nous blind fish and crawfish from the lightless cabe lakes and ponds.

On studying the arcane habits of the species of bats that roost in these shadowy cabal's Today, Mammoth Cave has become a new frontier for research and discovery.

So far, almost 400 miles of passages of men explored with much more untouched by human lying beyond and for the visitors.

The rial treasures are here to discover for themselves.

The time is now.