- Hey, there's the group of cavers.
- Dude, let's do it.
I'm Amtchat Edwards with the U.S. Forest Service.
This is my good friend John,
John the Phenomenon.
We learned a ton today with
the cave ecologist and a geologist,
and now we kind of want to hang out with you guys.
Is that cool?
- Sure.
I'm taking this group of people on
the adventure of their life.
It looks like you guys have all the proper safety equipment
so follow me.
- Sweet.
- I've been a guide here for around five years
and people love coming underground to crawl, climb,
and see a world that is so different from the surface.
Our cave here at Blanchard Springs,
as well as many caves around the world,
offer a fun way to get out and explore.
There are even clubs called grottos
where you can learn more about how to explore caves safely
and with conservation in mind.
Alright guys, let's go explore some more passage this way.
- Actually I think I see Fernando and Gretchen over there,
we've really got to catch back up with our group.
- Alright, thanks for coming.
- This has been a ton of fun, thank you Zoey.
- See you.
- Bye now. - Bye.
- Hey guys.
- Hey.
- That was fun.
- It was so cool.
I wanted to go up every passage.
- Well that's why we enjoy mapping.
We document every little passage to see where it goes.
You never know where it might take you.
- And who knows,
we might be in the longest cave in the world.
- We learned that caves exist
in many places around the world
and people have always been interested in them.
The record of human activity in caves goes back centuries.
People have always used caves as pathways,
protection from the elements,
and places to live.
So let's watch this video and see
how other people view them.
- [Woman] This is the Unica River, located in Slovenia,
a tiny country in the center of Europe.
We will visit the mysterious origins of this river
in a place hidden away where most people have never seen.
Today's a special day for these children.
They're visiting a place
deep under the surface of the earth,
Planinska Jama.
Jama means cave in Slovenian.
At the entrance of the cave we see the Unica River
rushing to the surface over a dam,
which was once used to power a sawmill
but now is used by a hydroelectric power plant.
Before going inside the visitors must first unlock the gate,
which ensures that only people
that have permission to visit the cave can go inside.
This cave is part of an extensive cave system
where the science of cave biology was born.
It is here that the children's search
for cave animals begins.
The first stop is at a giant funnel
used in the past to study cave formation.
Next, the children notice bats.
Bats leave their droppings or guano behind,
which is an important food source for cave critters
such as these millipedes.
Cave animals are tiny and need to be searched for carefully.
The children are observing the remains
of a slender-necked beetle,
the first cave animal in the world
to be scientifically described.
Cave animals have special characteristics.
They lack body pigmentation and eyes,
but instead have elongated legs and antennae
to sense their environment.
The Postojna-Planina cave system holds the world record
for the highest number of different cave species
found in it.
In the waters the children found cave crustaceans.
But the most famous animal in the cave river is the proteus,
an amphibian which can only be found
in this part of the world.
The cave also shows sign of human presence.
In the first part of the 20th century
the military built many pathways through the cave,
including this tunnel through solid rock.
Before we end our visit of Planinska Jama
we can see where the Unica River begins
at the unique underground confluence
of the Rak and Pivka rivers.
We leave you with one last extraordinary cave experience,
true darkness.