Original subtitles

ON THE SHORES OF LAKE MICHIGAN,

A POPULAR BEACH SWALLOWS UP A CHILD...

...WITHOUT ANY SCIENTIFIC EXPLANATION

FOR HIS SUDDEN DISAPPEARANCE.

I HAVE NEVER SEEN ANYTHING QUITE LIKE THIS BEFORE.

WHAT COULD POSSIBLY CAUSE SUCH A TERRIFYING INCIDENT,

AND ARE OTHERS STILL AT RISK?

WHOA. WHOA, WHOA, WHOA, WHOA.

HOLY MOLY.

AND IN RURAL PENNSYLVANIA,

A BIZARRE ICE CAVE UPENDS THE LAWS OF NATURE...

THIS IS REALLY UNUSUAL.

...MELTING IN THE WINTER AND FREEZING OVER IN THE SUMMER.

THIS IS REALLY COLD.

WILL OUR HIGH-TECH TOOLKIT...

ARE YOU GUYS READY?

...FINALLY SOLVE THE CENTURY-OLD RIDDLE?

WHOA!

IT'S DEFINITELY AN ACTIVE PIT.

BURIED DEEP BELOW THE EARTH'S SURFACE,

THERE ARE COUNTLESS UNSOLVED MYSTERIES.

AND TODAY, WE FINALLY HAVE THE TOOLS TO UNLOCK THEM.

THAT'S AMAZING.

IT'S SUPER DEEP!

I'M ROB NELSON, A SCIENTIST AND EXPLORER

INVESTIGATING OUR PLANET'S HIDDEN DEPTHS.

- GETTING DEEPER. - HOLY MOLY, STEFAN.

AND HELPING ME UNCOVER THESE SUBTERRANEAN SECRETS

IS TECH SPECIALIST STEFAN BURNS.

OH, MY GOD. LOOK AT THAT!

TOGETHER...

I GOT SOMETHING!

...WE ARE UNCOVERING NEW LEADS IN OUR QUEST

TO SOLVE EARTH'S MOST ENDURING MYSTERIES.

- THERE WE GO. - WHOO!

THESE ARE THE SECRETS OF THE UNDERGROUND.

- Captions by VITAC-- www.vitac.com

CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS

ON THE SOUTHERN SHORE OF LAKE MICHIGAN...

...SITS A UNIQUE NATURAL OASIS,

INDIANA DUNES NATIONAL LAKE SHORE.

ARE WE GETTING CLOSE, STEFAN?

YEAH, JUST KEEP GOING STRAIGHT.

WHAT'S DRAWN STEFAN AND I TO THIS 15,000-ACRE COASTAL AREA

IS THE PRIDE OF THE PARK,

A 126-FOOT SAND DUNE RISING OFF THE BEACH CALLED MOUNT BALDY.

IT'S ON THIS GIANT SAND FORMATION THAT A FREAK ACCIDENT

CHANGED A FAMILY'S LIFE FOREVER.

IT'S A SITE WHERE SOMETHING REALLY UNUSUAL HAPPENED.

A 6-YEAR-OLD KID FELL INTO THE DUNES,

SWALLOWED UP BY THEM.

THE BOY WAS ON A FAMILY CAMPING TRIP,

BUT DURING A CASUAL HIKE UP THE DUNE WITH HIS FATHER,

HE SUDDENLY VANISHED.

THE ONLY EVIDENCE OF WHERE HE'D GONE

WAS A 12-INCH DIAMETER HOLE IN THE DUNE.

LOCAL AUTHORITIES WERE QUICK TO RESPOND

AND STARTED DIGGING WITH SHOVELS, BARE HANDS

AND ANYTHING ELSE THEY COULD FIND.

AFTER A 3 1/2 HOUR SEARCH,

THE BOY WAS FOUND ALMOST 11 FEET BELOW THE SURFACE WITH NO PULSE.

HIS PARENTS PREPARED FOR THE WORST,

BUT REMARKABLY, DOCTORS WERE ABLE TO REVIVE HIM,

AND 2 WEEKS LATER, HE WALKED OUT OF THE HOSPITAL.

BUT TO MAKE THE TRAGIC EVENT EVEN MORE TERRIFYING,

NO ONE WAS ABLE TO EXPLAIN WHAT EXACTLY HAD HAPPENED,

HOW A PUBLIC BEACH COULD SUDDENLY,

AND WITHOUT WARNING, SWALLOW UP A CHILD.

IT SEEMED TO DEFY ALL SCIENTIFIC EXPLANATION.

THE THING I FIND SO INTERESTING ABOUT THIS

IS THAT I HAVE NEVER HEARD OF SOMETHING

LIKE THIS EVER HAPPENING,

ESPECIALLY ON A SAND DUNE.

YEAH, THAT'S VERY BIZARRE.

GEOLOGICALLY, THAT SHOULDN'T HAPPEN.

NEWS REPORTS CALLED IT A SINKHOLE,

BUT ACCEPTED SCIENCE SAYS SINKHOLES

DON'T NORMALLY FORM IN SAND.

THEY'RE OFTEN FOUND IN AREAS

WHERE THE EARTH IS LIMESTONE OR CARBONATE ROCK.

WHEN WATER HAS ERODED THAT MATERIAL,

THE GROUND SUDDENLY GIVES WAY,

BUT SAND, GRAINY AND MALLEABLE,

SHOULD JUST COLLAPSE IN ON ITSELF

AS ANY CAVITY STARTS TO FORM.

SO HOW ON EARTH DID A DUNE SWALLOW UP A 6-YEAR-OLD BOY,

AND IS THERE STILL A RISK THIS TERRIBLE TRAGEDY

COULD REPEAT ITSELF?

STEFAN AND I AIM TO FIND OUT.

WOW, LOOK AT THIS.

THIS DUNE IS AT LEAST, LIKE, 80 FEET TALL.

IT'S, LIKE, SWALLOWING THOSE TREES.

THIS IS AMAZING.

WHEN IS THE RANGER SUPPOSED TO BE HERE?

THERE SHE COMES RIGHT NOW.

WE'VE ARRANGED TO MEET UP WITH NATIONAL PARK SERVICE BIOLOGIST,

LAURA BRENNAN,

TO LEARN MORE ABOUT WHAT'S GOING ON IN THIS LIVING LANDSCAPE.

BUT THESE DUNES ARE MOVING QUITE A BIT OVER THE PARKING LOT.

I CAN ACTUALLY REMEMBER WHEN I COULD WALK UP

TO THE BASE OF THOSE TREES RIGHT THERE.

REALLY? HOW LONG HAS IT BEEN?

NOT THAT LONG.

AFTER THE INCIDENT, THE NATIONAL PARK SERVICE CLOSED THE DUNE

UNTIL IT COULD BE DEEMED SAFE FOR THE SITE'S

NEARLY 2 MILLION ANNUAL VISITORS,

SO IT REMAINS OFF-LIMITS TO THIS DAY.

IS IT DANGEROUS, OR ARE WE FINE GOING UP THERE?

YOU KNOW, SINCE I'M HERE, I'LL WALK ALONG WITH YOU

AND MAKE SURE EVERYBODY IS SAFE.

SO, IN THEORY, THERE COULD STILL BE HOLES THAT SUCK PEOPLE DOWN?

ABSOLUTELY.

LAURA LEADS US UP THE PATH TOWARDS THE DUNE,

SHOVELS IN HAND.

NOT HIGH-TECH TOOLS,

BUT IF ANYONE GETS SUCKED UNDER THE SAND,

WE'LL BE ABLE TO DIG THEM OUT QUICKLY.

RESTRICTED AREA.

YEAH, AND A RARE PLANT HABITAT.

IT'S GETTING STEEP.

THIS IS THE HARD PART, HERE.

BUT THE WORK IS WELL WORTH IT.

OH, WOW.

- WELCOME TO MOUNT BALDY. - THIS IS HUGE!

I THOUGHT IT WAS JUST A LITTLE HILL

FROM THE PARKING LOT,

BUT THIS IS... AND VERY, VERY EXPANSIVE.

THOUGH THE VIEWS ARE SPECTACULAR,

IT'S FRIGHTENING TO IMAGINE THE SAND

COULD BE CAPABLE OF CAVING IN SUDDENLY BENEATH OUR FEET.

LOOKING AROUND, SOMETHING ELSE CATCHES ME OFF GUARD.

WHAT IS THIS OVER HERE?

YOU KNOW, THAT'S THE FOUNDATION OF A BUILDING.

IT WASN'T BUILT ON THE DUNE.

IT WAS BUILT ON THE BACKSIDE OF THE DUNE IN THE FOREST.

- NO KIDDING? - YEAH.

AND OVER THE YEARS, THE DUNE HAS GONE UP AND OVER IT?

EXACTLY.

VARIOUS FORCES-- WIND, WEATHER, HUMANS--

ARE COMBINING TO SHIFT SAND FROM THE TOP AND BEACHSIDE,

EVENTUALLY COVERING UP STRUCTURES LIKE THIS ONE

ALONG THE PARK'S 15-MILE COASTLINE.

BUT THESE RUINS ARE NOWHERE NEAR THE LOCATION

WHERE THE BOY WAS SWALLOWED UP,

SO COULD THE ACCIDENT STILL BE CONNECTED

TO OTHER BUILDING REMAINS THAT HAVE BEEN ENGULFED?

WHEN RESCUERS WERE DIGGING THE BOY OUT,

THEY REPORTED COMING ACROSS NUMEROUS

SMALL HOLES IN THE SAND,

SOME UP TO 8 INCHES IN DIAMETER,

BUT ALMOST AS SOON AS THEY WOULD SPOT THEM,

THE OPENINGS WOULD COLLAPSE,

AND SAND WOULD RUSH IN TO FILL THE VOID.

SINCE THE INCIDENT, RANGERS HAVE CONTINUED TO FIND HOLES

IN THE SURFACE OF THE DUNE

AND ARE PRETTY CERTAIN THAT THEY ARE SOMEHOW CONNECTED

TO WHAT HAPPENED HERE.

SO HOW MANY OF THESE HOLES LIE BENEATH THE DUNE,

AND DO THEY POSE A RISK TO US?

I THINK WE HAVE TO GET EYES ON A HOLE OR TWO.

NOW REMEMBER, SOMETIMES, THERE COULD BE A HOLE

THAT YOU DON'T EVEN SEE ON THE SURFACE.

THE THING THAT'S SO HARD ABOUT THIS

IS THERE IS NO EVIDENCE,

REALLY, THAT WE CAN SEE OTHER THAN SAND.

I MEAN, IT'S NOT OBVIOUS AS TO WHAT CAUSED IT,

AND THAT'S WHAT'S BAFFLING EVERYBODY.

HAVING STUDIED BIOLOGY AND MARINE SCIENCES,

I KNOW FIRSTHAND HOW COASTAL AREAS

CAN TAKE ON A LIFE OF THEIR OWN.

WHEN SAND BECOMES SATURATED, WATER CAN DESTABILIZE IT,

TURNING IT INTO DANGEROUS QUICKSAND

AND PULLING IN WHOEVER WALKS OVER IT.

BUT THIS DUNE WAS BONE DRY THE DAY THE BOY FELL INTO IT,

SO THERE MUST BE SOME OTHER EXPLANATION

FOR THE BIZARRE OCCURRENCE HERE.

WHOA. WHOA, WHOA, WHOA, WHOA.

HERE WE GO.

HOLY MOLY. LOOK AT THAT.

BE CAREFUL.

AS SOON AS WE TRY AND PROBE THIS HOLE'S OPENING...

I THINK IT MIGHT HAVE ALREADY COLLAPSED IN ON ITSELF.

SO WE KEEP MOVING IN SEARCH OF ADDITIONAL HOLES

THAT MIGHT HELP US ANSWER HOW A CHILD

COULD HAVE BEEN SWALLOWED UP BY THIS DUNE.

OH, LOOK AT THIS, STEFAN.

WOW, LOOK AT THAT.

OH, YEAH, THAT'S A HOLE OF SOME SORT.

IT'S RIGHT NEXT TO A TREE TRUNK,

WHICH SEEMS TO BE SPROUTING OUT OF THE DUNE.

IT LOOKS LIKE THIS TREE STUMP HAS BURNT IN THE PAST,

EITHER THAT, OR HAD SOME BLACK FUNGUS ON IT.

THE HOLE APPEARS TO RUN DOWN ALONGSIDE THE TRUNK.

CAN YOU TELL HOW DEEP IT GOES?

LET ME PROBE IT.

UH...

ABOUT A FOOT.

OH, THAT'S DEEP.

WON'T BE A HOLE IN A SECOND, STEFAN.

BEFORE WE GO ANY FURTHER,

I WOULD LOVE TO SEE WHAT'S AT THE BOTTOM OF THIS.

THE SIZE AND SHAPE OF THESE HOLES

SEEM CONSISTENT WITH ANIMAL BURROWING.

I WANTED TO GET A LOOK INSIDE OF ONE TO SEE

IF THERE ARE ANY SIGNS OF ANIMAL ACTIVITY.

GIVEN THE DELICATE NATURE OF THESE OPENINGS

AND THEIR TENDENCY TO COLLAPSE IN ON THEMSELVES,

I DON'T WANT TO TRY DIGGING IN.

CAN WE GET THAT BOREHOLE CAMERA,

GET IT IN THERE AND CHECK IT OUT, LIGHT IT UP?

YEAH, WE CAN THROW IT IN THERE, SEE HOW FAR IT GOES.

I'LL GRAB IT.

OUR BOREHOLE CAMERA IS SPECIFICALLY USED TO VIEW

SMALL AREAS UNDERGROUND INACCESSIBLE TO THE NAKED EYE.

IT WILL ALLOW US TO SEE INSIDE THE HOLE

WITHOUT DISTURBING THE SURROUNDING SAND TOO MUCH.

ALL RIGHT. I HAVE THE CAMERA.

THIS THING IS SUPER COOL.

BASICALLY, THIS BOREHOLE CAMERA HAS A LITTLE LIGHT AT THE END

AS WELL AS A CAMERA, AND IT'S 25 FEET LONG,

SO WE CAN SNAKE IT INTO THESE SPOTS,

AND ONCE FULLY EXTENDED, IT HAS AN ARTICULATING HEAD.

AND THE END OF IT CAN MOVE AROUND.

WILL OUR CAMERA REVEAL THE PRESENCE OF ANIMAL BURROWS

OR GIVE US OTHER CLUES

AS TO WHAT'S CAUSING THESE BIZARRE HOLES TO FORM?

IT'S GOING DOWN.

2 INCHES, 3 INCHES,

4 INCHES.

AH, CRUD.

UNDERGROUND TECH EXPERT STEFAN BURNS AND I

ARE IN INDIANA ATTEMPTING TO EXPLAIN

HOW A YOUNG CHILD WAS SWALLOWED UP INTO A MASSIVE SAND DUNE.

WELL, LOOK AT THIS, STEFAN.

OH, YEAH. THAT'S A HOLE OF SOME SORT.

WE ARE USING OUR SPECIALIZED BOREHOLE CAMERA

ON A SMALL OPENING TO FIND OUT

IF BURROWING ANIMALS ARE HOLLOWING OUT THE DUNE

BENEATH OUR FEET,

MAKING IT AN UNSTABLE DEATH TRAP FOR ANYONE WALKING ABOVE.

IT'S GOING DOWN.

2 INCHES, 3 INCHES,

4 INCHES.

AH, CRUD. - OH, IT JUST FELL IN.

OH, CRUD.

IT KIND OF COLLAPSED IN ON ITSELF.

YEAH.

I MEAN, THAT'S THE BIGGEST HOLE WE'VE FOUND,

BUT THAT'S DEFINITELY NOT SOMETHING

THAT COULD SWALLOW A CHILD UP.

IT SEEMS THE BOREHOLE CAMERA WON'T GIVE US THE LOOK WE NEED

TO FIGURE OUT WHAT'S CAUSING THESE OMINOUS HOLES

TO APPEAR BENEATH THE SURFACE OF MOUNT BALDY.

WE HAVE TO FIND IT UNDERGROUND.

YEAH, I THINK IT'S TIME TO USE THE GPR

AND TO SCAN THIS ENTIRE AREA,

JUST BUILD A 3-D MAP OF ALL THE STRUCTURES UNDERGROUND.

GROUND-PENETRATING RADAR, CALLED GPR FOR SHORT,

WORKS BY FIRING RADIO WAVES INTO THE GROUND

AND SHOULD REVEAL ANY CAVITIES BURIED BENEATH THE SURFACE.

WHILE I KEEP LOOKING FOR HOLES,

STEFAN GETS TO WORK SETTING UP A GRID

SO THAT WE CAN DETERMINE IF ANIMAL BURROWS

WERE INDEED WHAT THE CHILD FELL INTO.

SO HE BEGINS THE SCAN, WHICH IS HARD WORK.

PUSHING IN SAND IS THE WORST.

BUT WILL IT PAY OFF?

LOOK AT THIS.

THESE ARE HUGE,

TWO PERFECT FEATURES, ONE AT 13 FEET,

AND ONE AT 8 FEET.

I'LL KEEP SCANNING TO SEE IF THERE'S MORE OF THEM.

AS STEFAN'S SCAN CONTINUES,

HE BEGINS TO SEE MORE AND MORE HOLES

RIGHT UNDERNEATH HIS FEET,

WHICH CAN BE DANGEROUS IF HE TAKES A WRONG STEP.

YES.

THAT SURVEY WAS BRUTAL, 60 BY 100 FEET,

BUT I SAW SO MUCH IN THERE.

STEFAN'S SCAN HAS REVEALED SOMETHING TERRIFYING.

THERE APPEAR TO BE NUMEROUS VOIDS

VARYING IN SHAPES AND SIZES

AND EVEN POSITIONED AT DIFFERENT ANGLES.

THIS UNDERGROUND LABYRINTH APPEARS TO BE STRUCTURED

LIKE SWISS CHEESE,

MAKING IT SEEM LESS LIKELY THAT ANIMAL BURROWING IS INVOLVED.

THESE HOLES DO NOT MAINTAIN A CONSISTENT DIAMETER

THAT WE WOULD NORMALLY SEE WITH ANIMAL ACTIVITY.

SO IF ANIMAL BURROWS ARE NOT TO BLAME FOR THE BOY'S ACCIDENT,

THEN WHAT IS?

IF WE CAN IDENTIFY WHAT CAUSED THESE SUBTERRANEAN POCKETS

TO FORM,

WE MAY BE ABLE TO PREVENT THIS FROM HAPPENING AGAIN

AND ENSURE THE SAFETY OF THE 2 MILLION PEOPLE

THAT VISIT EACH YEAR.

WE ARRANGE TO MEET UP WITH KEVIN RUSSELL...

KEVIN. - HEY, GOOD MORNING, ROB.

...A CARTOGRAPHER FROM THE INDIANA GEOLOGICAL SURVEY.

HE HAS SOME OLD MAPS AND AERIAL PHOTOS OF THE AREA

THAT MIGHT SHED SOME LIGHT ON WHAT'S CAUSING THIS DUNE

TO TAKE ON A SWISS-CHEESE-LIKE STRUCTURE.

HERE IS AERIAL IMAGERY FROM JUNE 1, 1939,

OF THE INDIANA SHORELINE,

AND THIS IS FROM 1958, TAKEN SEPTEMBER 13th.

OKAY, LET'S COMPARE THESE TWO TO EACH OTHER REAL QUICK.

LET'S SEE.

THOUGH MORE RECENT AERIAL SURVEYS HAVE BEEN DONE,

THESE MID-CENTURY MAPS ALLOW US TO SEE

WHAT THE DUNE HAS COVERED UP IN THE PREVIOUS CENTURY,

GIVING US MORE CLUES AS TO WHAT MIGHT BE

LYING HOLLOW BENEATH IT.

WE ALREADY KNOW THAT THE DUNE HAS BEEN MOVING INLAND

FOR THE PAST FEW DECADES,

BUT BY LOOKING AT THESE PHOTOS,

WE KNOW SEE HOW MUCH AREA

IT ACTUALLY ENGULFED IN ONLY 20 YEARS.

THESE MAPS ARE GREAT BECAUSE IT ALLOWS US

TO SEE WHAT COULD HAVE BEEN THERE BEFORE THE SAND WAS,

WHICH MIGHT ALLOW US TO FIGURE OUT

HOW AN AIR GAP WAS FORMED...

- YEAH. - ...THAT HE FELL INTO.

IF WE ARE ABLE TO PINPOINT WHAT EXACTLY ON THIS LAND

THE DUNE HAS COVERED SINCE 1939,

WE MIGHT BE ABLE TO EXPLAIN WHAT THE BOY FELL INTO.

THIS DUNE IS MOVING AT A FAST RATE,

OVERTAKING EVERYTHING IN ITS PATH.

YEAH.

AND ACCORDING TO THESE MAPS,

THAT EVERYTHING INCLUDES MAN-MADE STRUCTURES.

THIS IS, LIKE, A LITTLE DRIVEWAY,

AND THIS LITTLE SQUARE AT THE END,

I WOULD ASSUME THAT'S A HOUSE.

THERE'S ANOTHER ONE THERE.

CAN YOU SEE ANY STRUCTURES IN THERE?

WELL, THERE'S A STRUCTURE RIGHT THERE.

MM-HMM.

IT'S COVERED UP, NOW, IN THIS ONE COMPLETELY.

COULD THESE STRUCTURES BE WHAT STEFAN SAW ON THE GPR?

IF SO, MAYBE THAT HELPS EXPLAIN WHAT HAPPENED HERE.

DO YOU THINK THAT COULD BE WHERE THE KID FELL INTO

WAS ONE OF THESE OLD BUILDINGS?

IF A HOUSE WAS TO GET BURIED BY A SAND DUNE,

IT'S JUST GONNA BE A BIG POCKET OF AIR INSIDE,

AND EVENTUALLY, IF THERE'S ENOUGH WEIGHT ON TOP OF IT,

IT WOULD COLLAPSE.

DO YOU THINK THE THEORY HOLDS ANY WATER?

I THINK IT'S A POSSIBILITY.

COULD THIS DUNE BE RIDDLED WITH AN UNDERGROUND TOWN

OF OLD AND FORGOTTEN BUILDINGS

THAT COULD POTENTIALLY BE A DEATH TRAP

FOR ANY FUTURE VISITORS?

THIS IS MAKING ME WANT TO GET A 3-D MAP OF THE AREA

AND MAYBE TRY TO REFERENCE IT BACK TO THESE OLD MAPS.

SO WE COULD SHOW HISTORICALLY

WHERE THESE BUILDINGS WERE... - YEP.

...WHERE THE DUNE IS AND WHERE THE BUILDINGS ARE NOW,

AND WHERE THE GPR ANOMALIES WERE,

AND IF THEY ALL CORRELATE TOGETHER, BINGO.

WHILE STEFAN AND KEVIN CONTINUE TO STUDY THE MAPS,

I'M GOING TO FLY MY DRONE HIGH ABOVE THE DUNE

AND CAPTURE THE STILLS WE NEED,

CREATING A 3-D MAP TO HELP US FIGURE OUT

WHAT UNSTABLE UNDERGROUND WORLD

LIES BENEATH THE DUNE.

BUT HERE'S THE KICKER-- I CAN'T LAUNCH IT FROM LAND.

THE LAW REQUIRES ME TO BE AT LEAST 300 FEET OFFSHORE

TO PROTECT THE RESOURCES OF THE NATIONAL PARKS,

SO I'M HEADING OUT ON LAKE MICHIGAN TO MAKE THE MAP.

PHOTOGRAMMETRY WEAVES TOGETHER MULTIPLE 2-D IMAGES

TO CREATE A THREE-DIMENSIONAL MODEL,

IN THIS CASE, OF THE DUNE.

WE'LL BE ABLE TO LAYER THIS UP-TO-DATE IMAGE

ON TOP OF THE HISTORICAL AERIALS

AND THE GPR RESULTS TO EXPLORE OUR THEORY

THAT A LOST UNDERGROUND TOWN

MIGHT BE COLLAPSING BENEATH THE SAND,

CREATING THE DUNE'S BIZARRE HOLES.

HERE WE GO.

THE DRONE WILL BE RUNNING AN AUTOMATED FLIGHT PATH,

TAKING IMAGES FROM SPECIFIC POINTS

I'VE PLOTTED ON A GPS GRID.

OKAY, SO IT'S FLYING UP TO 400 FEET RIGHT NOW,

AND IT'S GONNA TAKE AN IMAGE EVERY 20 FEET

UP AND DOWN ACROSS THE DUNE.

COOL.

LAST ONE.

YEP, THAT ONE WAS GOOD.

WITH THE PHOTOGRAMMETRY A SUCCESS,

I'LL MEET BACK UP WITH STEFAN AND KEVIN

TO SHOW THEM THE RESULTS.

HEY, GUYS. - WELCOME BACK.

- SO SHOW US WHAT YOU'VE GOT. - YOU GUYS ARE GONNA LIKE THIS.

WE'VE USED SPECIALIZED SOFTWARE

TO KNIT THE 2-D IMAGES TOGETHER

TO CREATE A SINGULAR, 3-D IMAGE OF MOUNT BALDY.

SO YOU CAN ROTATE IT AROUND,

BUT YOU CAN SEE THE SHAPE

OF THE DUNE REALLY CLEARLY FROM HERE,

AND WHAT I FIND SO INTERESTING

IS THAT FROM THE OLD TOPOGRAPHIC MAPS,

MOUNT BALDY WAS HERE.

YES.

THE PHOTOGRAMMETRY HAS GIVEN US

THE MOST CURRENT MAP OF MOUNT BALDY.

WE WILL NOW BE ABLE TO CROSS-REFERENCE THIS IMAGE

OVER THE 1958 MAP IN ORDER TO VISUALIZE THE DISTANCE

THE DUNE HAS TRAVELED SINCE FROM AN AERIAL POINT OF VIEW.

IT HAS GIVEN US THE ABILITY TO USE THE PARKING LOT

AS A REFERENCE POINT TO SEE EXACTLY WHAT THE DUNE

HAS CONSUMED IN THE PAST 50 YEARS.

WHILE TAKING A CLOSER LOOK,

WE NOTICE THAT THERE ARE MORE THAN JUST BUILDINGS AND ROADWAYS

THAT THE DUNE HAS COVERED UP.

LOOK HOW IT'S OVERTAKING THIS FOREST.

WHEN I RAN THE GPR OVER THE AREA, I GOT TONS OF ANOMALIES,

MORE THAN CAN BE EXPLAINED JUST BY THE STRUCTURES IN THE AREA.

WITH THE ADDITION OF STEFAN'S GPR SCAN,

WE'LL BE ABLE TO CREATE A MORE THOROUGH IMAGE

OF ANY HOLES THAT LIE UNDERNEATH.

I MEAN, IT'S COMPLETELY ENGULFING THIS FOREST,

SO WHAT I STARTED THINKING ABOUT WHEN WE STARTED LOOKING AT THIS

IS THAT WE WERE HONING IN ON THESE STRUCTURES

THAT THE DUNE HAS ENGULFED, RIGHT?

YEAH.

BUT EVERY SINGLE ONE OF THESE TREES

IS TECHNICALLY A STRUCTURE.

THERE ARE SO MANY TREES AND SO FEW STRUCTURES

THAT THE PROBABILITY OF THE HOLE LINING UP

WITH THE POSITION OF A TREE

SEEMS FAR MORE LIKELY THAN ALIGNING WITH AN OLD BUILDING.

SO WHERE EXACTLY DID THE KID FALL INTO THE HOLE?

IN THIS GENERAL AREA RIGHT HERE.

OKAY.

ARE THERE ANY STRUCTURES THERE OR TREES?

NO, LOOK AT THAT.

SEE ALL THE TREES LYING UNDERNEATH

THE SURFACE OF THE DUNE?

- WHOA. - HERE, CHECK THAT OUT.

CHECK THAT OUT. - LOOK AT THAT.

COULD THESE TREES HAVE CREATED THE HOLE

THAT BURIED THE BOY ALIVE?

HONESTLY, THE WHOLE THING SEEMS VERY UNUSUAL TO ME.

STEFAN AND I ARE ON A MISSION

TO UNCOVER HIDDEN SECRETS BENEATH MOUNT BALDY

THAT COULD EXPLAIN WHAT CAUSED A 6-YEAR-OLD CHILD

TO GET SUCKED INTO AN UNEXPLAINED HOLE.

WE HAVE JUST COMBINED OUR GPR AND PHOTOGRAMMETRY MAPS

TO GET A COMPREHENSIVE LOOK AT THE DUNE'S MIGRATION PATH,

AND ONE THING IS BECOMING MORE EVIDENT.

LOOK AT THAT. SEE ALL THE TREES

LYING UNDERNEATH THE SURFACE OF THE DUNE?

- WHOA. - HERE, CHECK THAT OUT.

CHECK THAT OUT. - LOOK AT THAT.

THE DUNE HAS COVERED UP PARTS OF THE FOREST

WHERE TREES SEEM TO BE SCATTERED UNDERNEATH,

BUT IF THE HOLE WAS, AT ONE POINT, A TREE,

HOW COULD IT HAVE CREATED A VOID UNDER THE DUNE

FOR THE BOY TO FALL INTO?

I MEAN, THERE HAS TO BE SOME PROCESS AT PLAY

THAT'S RESPONSIBLE FOR DISINTEGRATING THESE TREES,

MAYBE THROUGH SOME DECOMPOSITION,

OR THERE'S SOMETHING THE SAND...

THE WAY I SEE IT,

IT EITHER IS SOMETHING IN THE SAND THAT'S CAUSING THIS,

OR IT'S SOMETHING WITHIN THE TREE ITSELF.

HOW DO YOU THINK THESE TREES INTERACT WITH THE DUNE

ONCE THEY'RE BURIED?

THE WHOLE THING IS SOMEWHAT PERPLEXING TO ME.

SAND DUNES WILL COMMONLY ENVELOP TREES

AND OTHER VEGETATION.

IN EXTREME CASES, SEISMIC ACTIVITY OR EXPOSURE

TO SEA LEVEL CHANGES

WILL COMPLETELY ENGULF GROVES OF TREES

IN SAND, MUD OR WATER.

IT'S A PROCESS THAT CAN RESULT IN WHAT'S CALLED A GHOST FOREST.

AREAS SUCH AS THE NESKOWIN GHOST FOREST IN OREGON

WERE COVERED IN SEDIMENT,

PRESERVING THE TREE STUMPS UNDERNEATH.

ANOTHER FOREST IN WYOMING BECAME ENCASED IN ALGAE,

PROTECTING IT FROM NATURAL ELEMENTS THAT CAUSE DECAY.

PETRIFICATION OCCURS WHEN TREES ARE SHIELDED

FROM DECOMPOSITION LIKE THIS.

SOLID MINERALS THEN REPLACE THE ORGANIC MATERIAL,

A PROCESS THAT WOULD NOT CREATE THE EMPTY CAVITIES

WE'VE SEEN ON MOUNT BALDY.

THESE TREES WERE POTENTIALLY RESPONSIBLE FOR THE INCIDENT,

THEN THE TREES HARDENING AND PETRIFYING

WOULD BE THE EXACT OPPOSITE

OF WHAT WOULD ACTUALLY NEED TO HAPPEN.

THESE TREES WOULD NEED TO HOLLOW OUT SOMEHOW AND LEAVE A SPACE.

BUT EVEN IF THAT WERE TO HAPPEN,

WOULDN'T THE SURROUNDING SAND

JUST COLLAPSE BACK INTO THE TREE,

FILLING IN ANY HOLE IMMEDIATELY?

HONESTLY, I'VE NEVER SEEN THIS BEFORE,

AND I THINK WE'RE GOING TO NEED TO TAKE SOME SAMPLES,

GO SEE A TREE EXPERT.

RUNNING WITH OUR HYPOTHESIS, THE DECOMPOSING TREES

SOMEHOW LEFT BEHIND AIR GAPS BENEATH THE SAND.

I HEAD BACK OUT TO THE DUNE TO COLLECT SOME TREE SAMPLES.

OH, LOOK AT THAT.

THERE'S SOME SOIL RIGHT ON THE EDGE OF THAT TREE.

ANY DIFFERENT BIT OF SOIL IS IMPORTANT,

SO THIS STUFF AROUND THIS TREE, THAT'S HARDER, MORE CONDENSED.

IT FEELS LIKE IT'S BASICALLY THE DECOMPOSED TREE RIGHT THERE.

AND UPON FURTHER INSPECTION, ONE OF THESE SAMPLES CATCHES MY EYE.

LOOK AT THE FUNGUS GROWING ON THIS ONE.

I'LL TAKE THIS WITH ME.

WOULD THIS FUNGUS HAVE ANYTHING TO DO

WITH THE TREE'S DECOMPOSITION?

THERE'S ONLY ONE WAY TO FIND OUT,

SO WE'RE HEADING TO NEARBY INDIANA UNIVERSITY

TO MEET WITH PETE AVIS...

- HEY, HOW ARE YOU DOING? - PETE.

...A BIOLOGIST WHO ALSO SPECIALIZES IN MYCOLOGY,

THE STUDY OF FUNGI.

WHAT HAPPENS WHEN A DUNE ENGULFS A TREE?

SO THE TREE PROBABLY DIES,

AND THE SAND COMING ON TOP OF THE TREE

IS GONNA CUT OFF THE LIGHT,

AND THAT'S GONNA STOP THE TREE

FROM DOING PHOTOSYNTHESIS.

AND THEN PRESUMABLY,

DECOMPOSITION CAN START TO RAMP UP.

THIS CONFIRMS OUR SUSPICION

THAT THERE IS NO PETRIFICATION OF THE TREES OCCURRING,

BUT IT DOESN'T ANSWER THE QUESTION

OF WHY THE SAND WOULDN'T JUST SETTLE AROUND THE DECAYING TREES

AND FILL IN ANY POTENTIAL HOLES.

I'VE OFFERED UP MY SAMPLES FOR PETE TO TAKE A CLOSER LOOK.

THIS, WHICH I PULLED OFF THE SIDE OF ONE OF THE STUMPS,

WAS JUST BARELY EXPOSED.

I THOUGHT IT WAS REALLY INTERESTING

BECAUSE IT HAD LITTLE BITS OF FUNGUS.

YEAH, YEAH, YEAH.

SO I'M CURIOUS WHAT YOU CAN TELL FROM SOME OF THIS.

USUALLY, WHEN THEY'RE ASSOCIATED THIS CLOSE TO WOOD,

THEY'RE INVOLVED IN THE DECOMPOSITION OF IT,

AND THERE'S A LOT OF FUNGI

THAT DECOMPOSE THE CENTER OF THE TREE

AND BASICALLY STARTS ON THE INSIDE OF THAT TRUNK,

WORKS ITS WAY OUT.

IT DOESN'T TOUCH THAT OUTER RING.

AND SO YOU'VE GOT A CYLINDER AROUND A HOLLOW MIDDLE.

PETE TELLS US THAT FUNGI CAN ENTER THE TREE THROUGH THE BARK

AND DECAY THE INTERIOR PORTIONS CALLED HEARTWOOD.

THIS DECAYING PROCESS CAN TAKE YEARS,

WITH SOME FUNGI KNOWN TO DECOMPOSE WOOD

AT THE RATE OF 2 TO 3 INCHES PER YEAR,

AND AFTER BEING BURIED INSIDE A DUNE,

IT COULD TAKE A FEW DECADES FOR A TREE

TO BE COMPLETELY EATEN FROM THE INSIDE

LEAVING ONLY THE SHELL.

BASED ON THE OLD AERIAL MAPS WE'VE SEEN,

THIS TIME FRAME ALIGNS WITH THE RATE AT WHICH MOUNT BALDY

HAS BEEN ENGULFING THE SURROUNDING FOREST.

COULD THIS UNUSUAL DECOMPOSITION PROCESS

BE WHAT'S LEAVING BEHIND THE HOLES ON MOUNT BALDY

THAT CAUSED THE TRAGIC EVENT?

WE NEED TO FIGURE OUT IF THE FUNGUS WE FOUND ON SITE

IS THE KIND THAT DECAYS WOOD FROM THE CENTER OUTWARD,

SO PETE DECIDES TO TAKE A CLOSER LOOK AT OUR SAMPLE

UNDER A MICROSCOPE.

YEAH, THIS IS DEFINITELY ONE OF THE KINDS OF FUNGI

THAT WOULD BE INVOLVED IN DECOMPOSING

THE TREES FROM THE INSIDE OUT.

OH, WOW, LOOK AT THAT.

IT'S AN INCREDIBLE REVELATION,

SUGGESTING THAT THIS BIZARRE VARIETY OF FUNGUS

IS RESPONSIBLE FOR HOLLOWING OUT TREES BENEATH THE SAND DUNE,

LEAVING BEHIND DANGEROUS HOLLOW TUBES

SUPPORTED BY THE REMNANTS OF TREE BARK.

IT IS AMAZING TO THINK THAT SOMETHING AT THE MICROBIAL LEVEL

COULD BE THE CAUSE OF SUCH A HORRIFIC ACCIDENT,

AND IT'S A TRULY UNEXPECTED ENDPOINT TO OUR INVESTIGATION.

FOR NOW, THE DUNE REMAINS OFF-LIMITS

TO THE GENERAL PUBLIC,

BUT WITH THIS INFORMATION COMING TO LIGHT,

IT WILL ONLY BETTER INFORM THE U.S. PARK SERVICE

ON HOW TO BEST MANAGE THE DUNE,

PREVENTING TRAGIC ACCIDENTS FROM HAPPENING AGAIN IN THE FUTURE

AND POSSIBLY SAVING THE LIVES OF OTHER CHILDREN

THAT WISH TO MAKE THE SAME HIKE THAT THE YOUNG BOY MADE.

OKAY, ON THE ROAD AGAIN. I'M STOKED.

AND NOW WE'RE HEADING TO A MYSTERIOUS SUBTERRANEAN LOCATION

ON THE EAST COAST THAT'S PUZZLED SCIENTISTS

SINCE ITS DISCOVERY IN 1894.

IN COUDERSPORT, PENNSYLVANIA,

NESTLED IN THE APPALACHIAN MOUNTAINS,

IS A NATURAL ODDITY THAT DEFIES THE LAWS OF NATURE,

A NEARLY 40-FOOT MINE UNLIKE ALMOST ANY OTHER ON EARTH

HAS BEEN PRODUCING SPARKLING CLEAR ICE IN THE SUMMER

THAT MELTS IN THE WINTER.

FIRST DISCOVERED IN THE LATE 19th CENTURY

BY A PROSPECTOR SEARCHING FOR SILVER,

THE MINE WAS USED BY LOCALS

TO REFRIGERATE MEAT IN THE SUMMER MONTHS.

AS WORD SPREAD, VISITORS FLOCKED TO MARVEL AT THE ICY CURIOSITY,

BUT NO ONE COULD EXPLAIN WHAT STRANGE FEAT OF NATURE

COULD CAUSE SUCH AN ODD PHENOMENON.

SO STEFAN AND I ARE GOING TO CHECK THIS OUT FOR OURSELVES.

HEY, ROB, SO YOU WANT TO TURN LEFT UP HERE.

YEAH, GOOD IDEA.

WE'RE BRINGING ALONG A CADRE OF EQUIPMENT

NEVER BEFORE USED HERE TO HOPEFULLY,

FINALLY GET AN ANSWER

TO WHAT'S BEEN BAFFLING PEOPLE FOR MORE THAN 100 YEARS.

HEY, GARY! - GOOD MORNING.

ROB NELSON, HOW ARE YOU DOING?

- FINE, SIR. - HEY, GOOD TO MEET YOU.

GOOD MORNING. WELCOME TO COUDERSPORT ICE MART.

WE'RE MEETING UP WITH GARY BUCHSEN,

WHO OWNS THE PROPERTY THAT HOUSES THE COUDERSPORT ICE MINE.

YEAH, I WANT TO SEE THIS THING.

OKAY, GREAT. YOU'RE GONNA GO THROUGH HERE.

WOW. IT'S COLD.

THE DOORWAY IS LIKE A PORTAL.

OUTSIDE IS SWELTERING SUMMER HEAT,

INSIDE, A BITING, FRIGID AIR.

HOLY MOLY, LOOK AT THAT.

THAT'S FREEZING.

IT IS NOT UNUSUAL

TO HAVE 50 DEGREES' DIFFERENCE IN TEMPERATURE

WHEN WE'RE ONLY 15 FEET AWAY.

THE CHILL EMANATES FROM THE CENTERPIECE WITHIN THE MINE,

A 14-BY-34-FOOT VERTICAL SHAFT CASCADING WITH ICICLES.

THIS IS REALLY UNUSUAL.

OBVIOUSLY, IT'S A VERY UNUSUAL, VERY UNIQUE...

IT'S ONE OF THE COLDEST SPOTS

IN THE EASTERN PART OF UNITED STATES

ALL THE WAY FROM FLORIDA CLEAN UP INTO MAINE.

WE HAVE A LOT OF PEOPLE FROM DIFFERENT COMPANIES

AND FROM DIFFERENT COLLEGES.

WE'VE HAD GEOLOGISTS COME OUT HERE, AND THEY JUST SAY,

"YOU KNOW, I DON'T KNOW WHAT'S HAPPENING HERE."

SOME BELIEVE THAT THE MINE IS PART OF A DYNAMIC CAVE SYSTEM

WITH MULTIPLE ENTRANCES WITH COLD AIR

FLOWING INTO THE MINE FROM VARIOUS PASSAGEWAYS,

BUT THE EXISTENCE OF SUCH ENTRANCES HAS NEVER BEEN PROVEN,

AND EVEN IF THEY WERE FOUND,

WHERE WOULD ALL THE SUBFREEZING AIR BE COMING FROM?

DUE TO COLLAPSING ROCK WITHIN THE CAVERN,

ACCESS HAS BEEN PROHIBITED FOR YEARS,

BUT THE PROSPECT OF UNCOVERING THE SOUGHT-AFTER EXPLANATION

IS TOO TEMPTING,

AND WE'RE GOING IN AT OUR OWN RISK.

BUT, OBVIOUSLY, WHEN YOU GO DOWN IN THERE,

IF AN ICICLE OF WHATEVER WEIGHT WOULD FALL OFF

AND HIT YOU, YOU'RE AT YOU'RE OWN RISK.

WELL, IF IT FALLS ON ANYBODY,

IT'S PROBABLY GOING TO FALL ON STEFAN.

OKAY.

THAT'S JUST USUALLY HOW IT WORKS.

UNLOCKING THIS MYSTERY REQUIRES BUSTING OUT OUR TOP TECH...

IT LOOKS GOOD. YOU GUYS ARE...

YEP. GOOD DRIVING.

...AS WELL AS SOME SCIENTIFIC INGENUITY.

THIS IS COOL.

WE'RE AT THE LEGENDARY

COUDERSPORT ICE MINE IN PENNSYLVANIA,

WHERE ICE MYSTERIOUSLY FORMS IN THE SUMMER

AND MELTS IN THE WINTER,

AND STEFAN AND I ARE ON A MISSION TO FIND OUT WHY.

OKAY.

AND I'M THINKING THAT WE'RE GONNA WANT

TO COME RIGHT DOWN THROUGH HERE.

WE'RE ENTERING WITH EXTREME CAUTION.

I'M ACTUALLY GONNA GET IN FROM THIS SIDE THERE.

I THINK THAT'LL BE EASIER.

THE ROCK STRATA HOLDING UP THIS MINE RESEMBLES A GAME OF JENGA.

IF A LOAD-BEARING PIECE GETS PUSHED OR KICKED HARD ENOUGH,

IT'S POSSIBLE THE WHOLE SHELF COULD TOPPLE.

GOT IT? OKAY, I'M COMING DOWN, TOO.

ALL RIGHT.

IT'S ALSO VERY SLIPPERY DOWN HERE.

ALL RIGHT.

WOW, LOOK AT THIS.

OH, MY GOODNESS.

WOW, THIS IS INCREDIBLE.

THIS IS REALLY COOL.

- YEAH. - AND IT'S REALLY COLD.

IT IS FREEZING.

I'M TRYING TO OPEN THIS POCKET UP FOR MY HANDS,

AND MY FINGERS ARE GOING NUMB.

I HAVE A COUPLE CAPS FOR YOU GUYS,

ONE SIZE FITS ALL.

OH, THIS IS FANTASTIC.

OH, THIS IS VERY SOFT, TOO.

BUT IT JUST MIGHT KEEP YOUR EARS A LITTLE BIT WARMER.

HOW DO I LOOK, PRETTY GOOD, RIGHT?

ALL RIGHT. WE'RE DOING THIS.

WE'RE DOING THIS.

WE ONLY JUST DESCENDED INTO THE CAVE,

AND THE PECULIARITIES ARE GLARING.

NOT ONLY DOES THE ICE CAVE DEFY SUMMER, BUT GRAVITY, TOO.

THE ICICLES GROW UP, NOT DOWN.

LOOK AT THE ICE ITSELF.

SEE HOW CLEAR IT IS? - UH-HUH.

THIS ISN'T WATER THAT'S, LIKE, LET'S SAY,

RISING FROM THE SURFACE THAT HAS MINERALS IN IT.

IT'S VERY LIKELY

THAT THIS IS BEING DRAWN OUT OF THE AIR.

NOW, LOOK AT THAT.

IT'S PRECIPITATING OUT OF THE AIR?

YEAH.

THE RISING ICE IS A CLUE.

THIS PRECIPITATION OCCURS WHEN MOIST AIR COOLS DRASTICALLY.

WHEN THE HUMID AIR FROM ABOVE IS PUSHED DOWNWARD

INTO THE FRIGID CAVERN,

WATER PARTICLES BEGIN TO SOLIDIFY,

EVENTUALLY TURNING INTO ICE,

BUT WHERE IS ALL THIS COLD AIR COMING FROM?

YEAR-LONG ICE CAVES HAVE BEEN DOCUMENTED IN CHINA,

AUSTRIA AND SLOVAKIA,

BUT ALL THESE HAVE DIFFERENT CONTRIBUTING FACTORS--

AIRFLOW FROM A NETWORK OF CAVES,

THE PRESENCE OF WATER OR COLD TRAPS.

NONE OF THESE FACTORS HAVE BEEN CONFIRMED AT THIS SITE,

AND SO FIRST, WE'RE GOING IN SEARCH

OF THE MOST LOGICAL SOURCE--

SOME SUBTERRANEAN CAVE SYSTEM

THAT'S RELEASING COLD AIR INTO THE MINE.

WE SHOULD DO SOME AIRFLOW TESTS TO GO AHEAD

AND, YOU KNOW, FIND OUT

IF THERE IS ANY DRAFTS IN HERE.

TO TEST OUT IF AIR IS BEING PUSHED INTO THE MINE

BY SUCH A SYSTEM, WE'LL USE AN AIRFLOW METER.

IT WILL MEASURE THE SPEED OF ANY AIR CURRENT

THAT IS FLOWING FREELY IN OR OUT OF THE MINE,

SO WILL IT EXPOSE ANY HIDDEN PASSAGEWAYS

DEEP WITHIN THESE WALLS?

TRY THAT GUY RIGHT BEHIND YOU,

BUT STICK IT IN AS FAR AS YOU CAN.

GOSH, THERE IS A DEEP HOLE RIGHT THERE.

THIS IS A REALLY SMALL SPACE.

I CAN SEE WHY THEY DON'T WANT ANYBODY DOWN HERE.

IT'S KIND OF SKETCH.

YEAH.

THE FOUNDATIONS OF THIS CAVE ARE A BIT PRECARIOUS.

IF ANY OF THIS ICE OR ROCK WERE TO DISLODGE,

IT'S POSSIBLE THE ENTIRE THING COULD COLLAPSE IN ON ITSELF.

WATCH YOUR HEAD, THERE.

OH, GOD, LOOK HOW LOOSE THAT IS.

IT'S BRITTLE.

- THIS IS ALL REALLY FRACTURED. - UH-HUH.

I MEAN, THERE ARE TONS OF, LIKE, LITTLE FISSURES AND GAPS.

AND IT'S CLEAR THERE AREN'T GOING TO BE ANY SHORTCUTS

IN THIS INVESTIGATION.

THIS CAVE IS RIDDLED WITH THOUSANDS OF TINY HOLES.

THE AIRFLOW COULD BE COMING FROM ANY ONE OF THEM.

I THINK WE NEED SOME WAY TO,

LIKE, TRACK THE AIR IF THAT MAKES SENSE.

WHAT MIGHT HELP IS SOMETHING THAT WILL GIVE US

A VISUAL AID OF THIS SPACE.

I BROUGHT SOMETHING VERY SPECIAL JUST FOR THIS MOMENT.

SO CHECK IT OUT.

I'LL RIG UP WHATEVER IT TAKES TO GET THE JOB DONE,

LIKE ATTACHING A WALKING STICK TO A SMOKE MACHINE.

WE'VE GOT SMOKE.

OKAY, I'M GOING DOWN.

ALL RIGHT. BEST OF LUCK.

BY USING SMOKE, WE'LL BE ABLE TO VISUALLY DETECT

EVEN THE SLIGHTEST AIRFLOW IN THE MINE.

DO YOU SEE IT GOING INTO ANY FISSURES OR FRACTURES?

I DON'T SEE IT GOING INTO FRACTURES.

SO WE'RE GETTING CLEARLY THIS FOG COMING UP,

BUT IF THERE WAS A LARGE CIRCULATORY SYSTEM

THAT'S CONNECTED TO SOME CAVERN OR FRACTURE NETWORK...

YEP.

...IT WOULD HAVE WHISKED THIS SMOKE OUT

IN NO TIME FLAT, I THINK.

I MEAN, IT'S NOT DISSIPATING LIKE

THERE'S A HIGH-POWER FAN IN THERE,

WHICH, IF IT WAS CONNECTED TO SOME TUNNEL,

LIKE MANY IMAGINE,

THAT'S WHAT YOU WOULD THINK IT WOULD DO.

WITH NO APPARENT AIRFLOW FEEDING THIS MINE,

WHAT ELSE COULD EXPLAIN THE FREEZING TEMPERATURES

NEEDED TO MAINTAIN ITS ICY INTERIOR?

WE NEED TO RE-EVALUATE.

AS I MAKE MY WAY BACK UP TO THE SURFACE,

I START TO FEEL THE GROUND SHAKE JUST BELOW MY FEET.

WHOA.

STEFAN AND I HAVE BEEN GRANTED SPECIAL ACCESS

INTO THE MYSTERIOUS, AND OTHERWISE RESTRICTED

COUDERSPORT ICE MINE IN PENNSYLVANIA.

DO YOU SEE IT GOING INTO ANY FRACTURES?

AFTER COMPLETING AIRFLOW TESTS INSIDE THE PIT

IN SEARCH OF A COLD SOURCE...

I'M HEADING UP.

...IT'S STARTING TO LOOK LIKE THE MINE...

WHOA.

...ISN'T THE SAFEST PLACE.

THERE WAS A HUGE ROCK THAT WAS CANTILEVERED OUT.

WHOA, WHAT HAPPENED?

WELL, THE ENTIRE SHELF JUST FELL RIGHT BELOW THERE.

OH, MY GOD.

THAT WHOLE PILE DOWN THERE BASICALLY JUST FELL IN.

THE MINE IS LINED WITH A SEDIMENTARY ROCK CALLED SHALE.

IT IS COMPOSED OF MINERALS AND IS FLAKY AND EASY TO CRACK.

AS THE ICE MELTS, IT FREES UP THE ROCK,

CAUSING IT TO COLLAPSE.

THE LONGER WE'RE IN THERE, THE MORE DANGEROUS IT BECOMES.

YOU CAN HEAR IT FALLING STILL.

- YEAH, YEAH, YEAH. - IT'S STILL FALLING.

WE SHOULDN'T GO DOWN THERE.

THAT'S PROBABLY 1,000 POUNDS OF ROCK THAT JUST FELL.

IT'S DEFINITELY AN ACTIVE PIT.

ALL RIGHT.

WE'RE GOING TO HAVE TO USE SOME HIGH-TECH EQUIPMENT

TO SOLVE THIS MYSTERY,

AND I KNOW JUST THE RIGHT PEOPLE TO GO TO.

WOW, LOOK AT THIS PLACE.

FINALLY MADE IT TO THE LAB.

YEAH.

YOU READY TO GEEK OUT A LITTLE BIT?

YEAH, I'M REALLY EXCITED TO CHECK IT OUT,

AND HOPEFULLY, THEY HAVE SOME TECH FOR THAT ICE MINE.

THE NEXT STOP IN OUR INVESTIGATION IS TO VISIT

THE UNIVERSITY OF PENNSYLVANIA'S ROBOTICS TEAM

IN PHILADELPHIA.

HEY. - HEY, GOOD TO SEE YOU AGAIN.

- HOW'S IT GOING, YASH? - GOOD TO SEE YOU.

GOOD TO SEE YOU GUYS AGAIN.

WELCOME TO THE GRASP LAB. - YEAH.

YASH MULGAONKAR IS ONE OF ITS ROBOTICS EXPERTS.

SO WE HAVE THIS ICE MINE, BASICALLY,

A LITTLE HOLE IN THE GROUND

OUT IN WESTERN PENNSYLVANIA,

AND IT'S REALLY WEIRD BECAUSE IN THE WINTERTIME,

THE ICE MELTS,

AND IN THE SUMMER, THE ICE BUILDS.

SO WE REALLY NEED YOUR HELP BECAUSE WE WANT TO FIGURE OUT

WHY THIS ICE IS FORMING,

BUT WE CAN'T QUITE DO IT WITH THE TECH THAT WE HAVE.

THE CAVE IS PRETTY DANGEROUS.

EVEN WHILE WE THERE, THERE WAS THIS LEDGE BROKE OFF,

COULD HAVE CRUSHED US.

DO YOU HAVE SOMETHING YOU THINK MIGHT WORK IN THERE?

WHAT ABOUT A FLYING VEHICLE?

THAT COULD WORK.

SO THE SMALLEST ONE WE HAVE,

THIS IS SOMETHING THAT I'VE BEEN WORKING ON.

THIS TINY DRONE IS PROTECTED BY A CARBON-FIBER CAGE

IN CASE IT COLLIDES WITH ANYTHING.

LET'S MAKE IT FLY.

YOU'RE GONNA MAKE IT FLY RIGHT NOW?

YES. READY?

3, 2 AND 1.

- WOW. - OH, MY GOSH.

LOOK AT THAT. - THAT'S AWESOME.

THAT IS COOL.

WHAT DO YOU THINK?

I'M IMPRESSED.

OH, WOW.

SO THIS WILL GIVE YOU A VIDEO

OF WHAT THE MINE LOOKS LIKE FROM THE INSIDE.

OKAY.

YEAH, WE'VE ALREADY DONE A VISUAL SURVEY.

WELL, THIS IS COOL, BUT I THINK WE'RE GONNA NEED SOMETHING

THAT CAN SCAN THE ROOM AND GET A DETAILED MAP OF IT.

OKAY.

WE HAVE ROBOTS THAT HAVE A HIGH-RESOLUTION LiDAR.

IT'S GOT BEAMS

AND CAN SPIN ALL 360 DEGREES AROUND.

OH, OKAY.

LiDAR STANDS FOR LIGHT DETECTION AND RANGING.

IT USES PULSES OF LIGHT TO SCAN SURFACES IN FINE DETAIL

THAT WOULD OTHERWISE GO UNSEEN.

I THINK WE NEED A LiDAR UNIT LIKE THIS...

MM-HMM.

...BECAUSE IT'LL GIVE US THE RESOLUTION WE NEED.

THIS WILL CREATE THE FIRST-EVER 3-D MAP OF THE CAVE.

IF THERE IS A CAVITY ON THE OTHER SIDE OF THE WALL

OR A WATER SOURCE LEADING INTO THE MINE,

THE LiDAR SHOULD BE ABLE TO DETECT IT.

- WE HAVE THE TRUCK... - OH, YEAH.

...SO WE COULD USE THE RC TRUCK AS A BASE.

- YEAH. - LOOK AT THAT.

WE HAVE A HANDHELD LiDAR,

BUT THE CAVE IS TOO DANGEROUS.

WE NEED SOMETHING TO HELP US OPERATE IT REMOTELY.

ALL RIGHT. LET'S GET TO WORK.

BY ATTACHING THE LiDAR ONTO THE TRUCK,

THIS MAKESHIFT MACHINE WILL BE ABLE TO SQUEEZE INTO TIGHT SPOTS

AND DETECT ANY OPENINGS BEHIND THE CAVE WALLS.

OKAY.

SOUNDS LIKE IT'S EXACTLY WHAT WE NEED TO SOLVE OUR PROBLEM.

- YEAH, IT'S PERFECT. - ALL RIGHT.

I THINK WE HAVE A ROBOT THAT WE LIKE.

- OKAY. - SO SHOULD WE GO TEST IT OUT?

- LET'S TEST IT OUT. - OKAY.

WILL THIS ROBOT BE ABLE TO NAVIGATE

THE ICE CAVE'S ROCKY BOTTOM

IN ORDER TO CREATE A MAP

EXPLAINING HOW THE ICE IS CREATED?

AW, SO CLOSE.

STEFAN AND I ARE BACK AT COUDERSPORT ICE MINE

WITH A LiDAR UNIT ATTACHED TO A REMOTE-CONTROL TRUCK.

GOT IT.

WILL OUR HIGH-TECH DEVICE FINALLY REVEAL

THE COLD SOURCE INSIDE THE ICE MINE,

OR WILL THIS CENTURY-OLD MYSTERY REMAIN AN UNSOLVED PUZZLE?

ARE YOU GUYS READY?

OKAY, WE GOT A POINT CLOUD. AND WE ARE GOOD TO GO.

THE LiDAR WILL SPIN AROUND, USING LASERS TO SCAN THE CAVE.

WE'LL BE ABLE TO USE THE READINGS

TO CREATE THE FIRST-EVER 3-D MAP OF THIS ODD PLACE,

POINTING OUT ANYTHING THE AIRFLOW METER

OR SMOKE MACHINE COULDN'T PICK UP.

IT WILL ALSO PROTECT US FROM BEING CRUSHED

BY CRUMBLING ROCKS.

HOW IS IT LOOKING OVER THERE WITH THE LiDAR?

IT LOOKS GOOD. YOU GUYS ARE...

YEP, GOOD DRIVING.

THERE'S THIS ONE SIDE THAT'S A LITTLE SLIM

IN TERMS OF ITS POINT CLOUD.

- UH-HUH. - WE NEED TO FILL IN THIS GAP

THAT'S ON THE OPPOSITE SIDE OF THE ICE CAVE.

OKAY, SO YOU CAN SEE HERE, YOU JUST GOT TO GO STRAIGHT,

AND YOU'LL GET AROUND THE LADDER.

THE TERRAIN IS TRICKY, EVEN FOR THIS REMOTE-CONTROL TRUCK.

- AW, SO CLOSE. - THERE IT IS.

NICE. ALL RIGHT.

LET'S GRAB THE ROBOT,

AND WE'LL HEAD BACK TO THE LAB...

- AWESOME. - ...LET YOU GUYS PROCESS IT.

NOT BEING ABLE TO UNCOVER ANYTHING

WITH OUR PREVIOUS TECH

HAS ONLY HEIGHTENED MY CURIOSITY,

BUT WILL THE LiDAR FINALLY REVEAL

HOW THE ICE FORMS DURING THE HOT SUMMER MONTHS

WHILE MELTING IN THE WINTER?

THIS IS EXCITING.

IT'S, LIKE, ALL THAT WORK FINALLY COMES DOWN

TO PROCESSING IT.

YEP.

YEAH, WE'RE HOPING THAT THIS ILLUMINATES

THE SUBJECT A LITTLE BIT BECAUSE WE RAN INTO SO MANY ROADBLOCKS

THROUGHOUT THIS ENTIRE INVESTIGATION.

SO HOPEFULLY, OUR CUTTING-EDGE MAP

WILL HOLD THE ANSWERS.

ALL RIGHT. SO HERE WE GO.

LET'S GET THIS THING OPENED.

ARE WE ALL READY? WE ALL READY?

HERE IT COMES.

- OH. - COME ON.

COME ON.

HEY, LOOK AT THAT.

THAT'S ACTUALLY A GREAT ANGLE.

THIS IS UP LOOKING DOWN INTO...

IMMEDIATELY, WE NOTICE SOME FASCINATING POINTS

ON OUR 3-D MAP.

WOW. - LOOK AT THAT RIGHT THERE.

THESE POINTS REPRESENT SMALL EMPTY CAVITIES

JUST BEYOND OUR REACH INSIDE THE WALLS.

SO IT LOOKS LIKE WE HAVE SOME POINTS OVER HERE

TO THE SIDE THAT REALLY DIG OUT.

ACTUALLY, OH. THAT'S A BIG AMOUNT OF POINTS

THAT ARE OUTSIDE OF THE NORMAL WALL.

THAT IS UNUSUAL.

COULD THESE POINTS BE A FACTOR IN HOW THE MINE

MAINTAINS ITS FRIGID TEMPERATURES IN THE SUMMERTIME?

SO WE'RE SEEING POINTS, HERE, THAT EXIST OUTSIDE OF THE CAVE

THAT WE WERE IN,

AND, YOU KNOW, THIS LiDAR LASER SHINES THROUGH

AND THEN BOUNCES BACK AND STORES A POINT FROM OUTSIDE.

THAT MEANS THAT'S AN OPENING THAT WE WEREN'T ABLE TO SEE.

YEP.

THAT'S PRETTY GOOD PROOF OF A FISSURE AND FRACTURE NETWORK

THAT MIGHT LEAD TO WHAT'S FEEDING THIS COLD SPOT.

WELL, THIS IS ENCOURAGING.

WHAT WE HAVE UNCOVERED MIGHT ACTUALLY BE THE ANSWER

TO THIS LOGIC-DEFYING CAVERN.

OUR CUTTING-EDGE MODEL HAS REVEALED

LITERALLY THOUSANDS OF TINY FISSURES AND CREVICES

IN THE CAVE WALLS,

WHICH SUGGEST THE POSSIBILITY OF A NEW THEORY.

WHEN WINTER ARRIVES, THESE EMPTY FISSURES TRAP

IN THE NATURAL COLD AIR.

THE CAVITIES HOLD ONTO THIS AIR,

KEEPING THE MINE CHILLY THROUGHOUT THE SUMMER MONTHS.

AS THE COLD TEMPERATURES WITHIN THE FISSURES FADE,

IT THEN BEGINS TO TRAP THE HOT SUMMER AIR,

ENSURING THE CAVE IS WARM ENOUGH TO MELT AWAY

ANY ACCUMULATING SNOWFALL IN THE WINTER.

IN OTHER WORDS, THE WALLS THEMSELVES ACT LIKE AN ICE PACK

INSIDE A LUNCH BOX,

BUT IN THIS CASE COLD ENOUGH TO CREATE THE ICICLES WE HAVE SEEN.

COOLEST ROBOTICS TEAM WE KNOW.

YEAH.

AND WE'LL DEFINITELY BE BACK.

WE WILL DEFINITELY BE BACK.

YOU'RE MORE THAN WELCOME TO COME BACK ANY TIME.

AWESOME.

WHETHER IT'S AN UNDERGROUND NETWORK

OF FUNGI-INFESTED TREES

CAUSING A TRAGIC ACCIDENT ON THE SHORES OF INDIANA,

OR A SERIES OF MICROSCOPIC FISSURES

TRAPPING COLD AIR IN THE RURAL MOUNTAINS OF PENNSYLVANIA,

SOMETIMES, THE ANSWERS TO OUR QUESTIONS ARE HIDDEN

JUST BEYOND OUR REACH.