(JONAS) YOU KNOW WHEN YOU GET TO A NEW PLACE AND RIGHT AWAY YOU FEEL THAT THERE'S SOMETHING SPECIAL ABOUT IT BUT YOU CAN'T QUITE PUT YOUR FINGER ON WHAT IT IS?

THAT'S EXACTLY HOW I FELT THE FIRST TIME I VISITED THE DRIFTLESS REGION.

(♪ ) (KAITLYN) THIS LAND IS ANCIENT (♪ ) (OFF CAMERA) HOLDING ONTO THE YELLOW.

ALRIGHT, THERE'S THE CAMERA.

AND HERE'S YOUR SAFETY.

(JONAS) THIS IS ME.

MY NAME IS JONAS STENSTROM AND I'M FROM SWEDEN BUT RIGHT NOW I'M HANGING ON THE EDGE OF A CLIFF BY THE MISSISSIPPI RIVER IN SOUTHERN MINNESOTA.

WHY?

WELL, WE'LL GET TO THAT IN A LITTLE BIT.

THIS HERE IS MY BEST FRIEND AND BUSINESS PARTNER, ROB NELSON.

(ROB) WE GOTTA FIGURE OUT WHICH WAY DEEPER WATER IS.

(JONAS) WE'RE BOTH BIOLOGISTS AND FILMMAKERS.

TOGETHER WE TRAVEL ALL OVER TO FIND AND DOCUMENT INTERESTING WILDLIFE STORIES.

IT STARTED AS A PASSION TO DOCUMENT NATURE AND NOW WE FEEL IT'S OUR MISSION TO SHOW OUR CHILDREN THAT INTERESTING NATURE STORIES CAN BE FOUND EVEN IN PLACES YOU DON'T EXPECT IT.

WHERE WE ARE RIGHT NOW IS ONE OF THOSE.

WE ARE IN THE DRIFTLESS REGION AN AREA LOCATED BY THE UPPER MISSISSIPPI RIVER FROM SOUTHERN MINNESOTA AND WISCONSIN TO NORTHERN IOWA, AND A SMALL SECTION OF NORTHWESTERN ILLINOIS.

THE REASON THIS REGION IS SPECIAL IS IN ITS NAME: DRIFTLESS, DRIFT, OR MORE SPECIFICALLY, GLACIAL DRIFT, IS A GEOLOGICAL TERM FOR MATERIAL TRANSPORTED AND LEFT BEHIND BY GLACIERS.

AT DIFFERENT TIMES IN HISTORY, MUCH OF THE LAND HAS BEEN COVERED BY GLACIAL ICE.

TIMES WE OFTEN REFER TO AS GLACIAL PERIODS OR MORE COMMONLY THE ICE AGES.

DURING THE LAST GLACIAL PERIOD, WHICH IS BELIEVED TO HAVE ENDED ABOUT 11,000 YEARS AGO, THE MILE THICK PACK OF ICE MOVED SOUTH FROM CANADA AND COVERED MUCH OF THE NORTHERN PART OF THE U.S.

IT'S DESTRUCTIVE FORCE CRUSHED EVERYTHING IN ITS WAY AND WHEN THE ICE EVENTUALLY DISAPPEARED, THE LAND UNDERNEATH WAS FOREVER CHANGED.

LITERALLY LEVELED TO THE GROUND EXCEPT HERE.

OF ALL THE KNOWN GLACIAL PERIODS, THE AREA WE TODAY CALLED THE DRIFTLESS REGION NEVER GOT COVERED BY THE ICE.

SOMEHOW THIS REGION GOT SPARED AND WHAT WAS LEFT BEHIND WAS AN ENVIRONMENT FILLED WITH INTERESTING STORIES.

WITH GREAT ENVIRONMENTAL AND CULTURAL IMPORTANCE.

BUT WHY DID ALL THESE GLACIAL ADVANCES MISS THE DRIFTLESS REGION?

THIS IS UNIQUE ON EARTH.

WE'RE HERE TO FIND SOME ANSWERS.

ROB IS REALLY THE ONE WHO TOLD ME HOW TO COME AND SEE THIS.

HE WAS HERE FILMING A FEW YEARS AGO AND THE MORE THE TEAM STARTED DIGGING INTO IT THE MORE THEY REALIZED THAT THIS WAS A TRULY UNIQUE PART OF THE WORLD AND THAT MOST PEOPLE HAD NO IDEA ABOUT IT.

THE TEAM LEFT WITH TOO MANY UNANSWERED QUESTIONS, STORIES THAT SEEMED TOO INTERESTING TO STAY UNDOCUMENTED.

ROB CALLED ME UP AND SAID, “HEY JONAS, GET THE CAMERA'S READY.

WE HAVE SOME PLACES TO VISIT.” SO HERE WE ARE BUT NONE OF THIS WOULD HAVE BEEN POSSIBLE WITHOUT OUR TWO LOCAL GUIDES, GEORGE HOWE AND TIM JACOBSON.

AS A BIOLOGIST BORN AND RAISED IN THE DRIFTLESS, GEORGE IS LIKE A WALKING BOOK OF STORIES ABOUT THE REGION.

(GEORGE) COUNTLESS FRAGMENTS OF MARINE ORGANISM LIFE CYCLE OF FRESHWATER MUSSELS.

AND TIM, EQUALLY AS FILLED WITH KNOWLEDGE ABOUT THE INS AND OUTS OF THE DRIFTLESS AND ALWAYS ARMED WITH THE CAMERA AND READY IF THERE'S SOMETHING TO DOCUMENT.

THEIR PASSION FOR THE DRIFTLESS IS REALLY THE REASON THIS STORY STARTED IN THE FIRST PLACE.

RIGHT NOW WE'RE ITCHING TO START LOOKING FOR SOME OF THE ANSWERS TO THE MANY QUESTIONS WE HAVE AND WHAT BETTER PLACE TO START THAN FROM THE SKY?

LUCKY FOR US, TIM IS ALSO A PILOT.

(♪ ) (♪ ) (♪ ) IT'S PRETTY AMAZING TO SEE THE MISSISSIPPI RIVER FROM THIS PERSPECTIVE.

THE HUGE AMOUNT OF WATER MOVING DOWNSTREAM AND CONSTANTLY RESHAPING THE RIVER VALLEY IN ITS WAY.

THE WATER PUSHING SEDIMENT AROUND, CUTTING THROUGH LARGE FLOODPLAIN FORESTS, AND CREATING A NETWORK OF LITTLE ISLANDS AND WINDING CANALS EVERYWHERE IN BETWEEN.

ONE EXCEPTION IS LAKE PEPIN, THE LARGEST LAKE IN THE WIDEST NATURAL SECTION OF THE ENTIRE MISSISSIPPI RIVER.

ANOTHER INTERESTING OBSERVATION WE MADE, WERE SMALL DOTS ON THE LANDSCAPE, SINKHOLES, THAT SEEM TO PEPPER THE FIELDS.

BUT THE MOST STRIKING FEATURES OF THE AREA ARE WITHOUT A DOUBT THE STEEP BLUFFS LINING THE MIGHTY MISSISSIPPI RIVER.

FROM THE GROUND THEY LOOK LIKE IMPRESSIVE HILLS, WITH SECTIONS OF VERTICAL EXPOSED ROCK THAT IS LAYERED IN BANDS WITH DIFFERENT COLORS, BUT FROM THE AIR THERE'S ALSO SOMETHING ELSE ABOUT THE BLUFFS THAT STANDS OUT.

ALL THE BLUFFS LINING THE RIVER AS WELL AS FURTHER INLAND ARE THE EXACT SAME HEIGHT.

LIKE THE PEAKS HAVE ALL BEEN SHAVED DOWN TO THE SAME LEVEL BUT INSTEAD OF JUST A FLAT PLATEAU, THE LAND IS DISSECTED BY VALLEYS BETWEEN THE BLUFFS CREATING THE STRIKING TOPOGRAPHY THAT IS CHARACTERIZING THE DRIFTLESS.

AND ALL THE STREAMS AND RIVERS SEEM TO ALSO EVENTUALLY LINK UP WITH THE MISSISSIPPI.

WHAT WE ARE SEEING ARE THE RESULTS OF THE UNIQUE GEOMORPHOLOGY THAT HAS SHAPED THE DRIFTLESS REGION.

“HOW?” IS THE DIFFERENT QUESTION.

BUT EVERYTHING IS LINKED.

THE STREAMS, THE BLUFFS, THE MISSISSIPPI RIVER.

AND TO UNDERSTAND THIS, WE MUST FIRST LOOK AT HOW THIS LAND WAS FORMED IN THE FIRST PLACE AND THE CLUES ARE IN THE BLUFFS.

(COLLIN) SO ONE OF THE THINGS I TALK ABOUT- YOU KNOW- WITH MY STUDENTS IS “WHAT DID THIS LANDSCAPE LOOK LIKE AT THESE VARIOUS POINTS IN TIME?” AND ONE OF THE THINGS I THINK IS REALLY NEAT ABOUT STUDYING ROCKS FOR INSTANCES.

THAT'S HOW WE KNOW, RIGHT?

THAT'S WHERE THAT INFORMATION COMES UP FROM ABOUT THE NATURAL HISTORY OF THE WORLD THAT WE LIVE IN.

(JONAS) COLLIN EXPLAINS THAT THE BLUFFS ARE MADE UP OF SEDIMENTARY ROCK THAT DATES BACK TO A TIME WHEN ALL OF THIS, AND IN FACT, THE WHOLE PLANET, LOOKED A LOT DIFFERENT.

(COLLIN) WHEN WE LOOK AT THE ROCKS THAT MAKE UP THE BLUFFS, THOSE ROCKS HAVE CLUES WITHIN THEM THAT TELL US THAT THIS WOULD HAVE BEEN A TROPICAL SEA THAT WE'VE HAD HERE 500 TO 450 MILLION YEARS AGO.

ALRIGHT?

WHICH IS CRAZY TO THINK ABOUT WHEN YOU LOOK AT THIS LANDSCAPE THAT WE SEE TODAY AND WE'RE IN THE MID LATITUDES IN THE NORTHERN HEMISPHERE.

(JONAS) LET'S STOP HERE FOR A MINUTE AND TAKE THIS IN.

WE ARE NOW ABOUT A THOUSAND MILES FROM THE ATLANTIC COAST TO THE EAST AND MORE THAN 1,700 MILES FROM THE PACIFIC COAST TO THE WEST AND ALL OF THIS WAS ONCE PART OF A SUBTROPICAL OCEAN.

(COLLIN) NORTH AMERICA WOULDA BEEN TILTED ABOUT 90 DEGREES ON ITS SIDE AND AND WE WOULD HAVE BEEN LOCATED AT ABOUT 20 OR SO DEGREES SOUTH LATITUDE IN THE SOUTHERN HEMISPHERE, RIGHT?

AND SO OVER TIME, NORTH AMERICA SPUN AND WORKED ITS WAY UP TO ITS MODERN-DAY LOCATION.

(JONAS) AND NEW SEDIMENT LAYERS WERE CONTINUOUSLY BEING DEPOSITED ON THE BOTTOM, SEALING IN ANOTHER CHAPTER IN GEOLOGICAL HISTORY.

THE RESULTING SEDIMENT LAYER CAKE WE SEE IN PLACES LIKE HERE IN THE DRIFTLESS IS LIKE A GEOLOGICAL CALENDAR, LOCKING IN MANY OF THE MARINE CREATURES THAT WERE PRESENT IN THESE WATERS AT DIFFERENT TIMES.

(JORDAN) JORDAN KJOME, FROM DECORAH, IOWA.

AND THIS IS MY FATHER, JOHN KJOME.

(JOHN) WE MET WHEN HE WAS BORN.

WELL I GREW UP PICKING ARROWHEADS WHICH BECAME FOSSIL-PICKING WHEN WE STARTED CANOEING.

AND SO I TALKED TO JORDAN ABOUT FOSSIL PICKING AND IT DIDN'T TAKE MUCH TO GET HIM HOOKED.

(JORDAN) TRUE STORY.

THE FLAT SPIRALS LIKE THESE ARE CALLED MACLURITES.

THE ONES WITH THIS SPIRAL ARE GASTROPODS.

HAVING STARTED AT A YOUNG AGE I THINK IT'S JUST A PART OF WHO I AM.

I FEEL LIKE THAT'S MY MAIN PASSION IS BEING OUT THERE IN NATURE AND EXPLORING AND BEING IN CAVES AND LOOKING FOR FOSSILS AND ARROWHEADS AND I THINK AS I STARTED AT A YOUNG AGE, YOU HOOKED ME.

(ROB) THIS IS AMAZING.

LIKE LOOK AT THIS PARTICULAR ROCK.

I MEAN I GUESS THESE ARE BIVALVES, LITTLE SEASHELL TYPE THINGS AND THE COOL THING IS THIS WAS 400 MILLION YEARS AGO AND YOU CAN STILL FIND THINGS THAT LOOK JUST LIKE THIS TODAY.

THE OTHER COOL THING IS THAT WE ARE NOWHERE NEAR THE OCEAN AND THESE ARE OCEAN ANIMALS AND THAT'S PRETTY AMAZING.

HOLY MOLY.

(JONAS) ASIDE FROM A CHANCE TO FIND FOSSILS, THERE ARE OTHER THINGS THAT INTRIGUE US ABOUT THIS SEDIMENTARY ROCK LAYER CAKE.

WHEN DIFFERENT LAYERS OF ROCK ARE STACKED ON TOP OF EACH OTHER LIKE THIS, INTERESTING THINGS CAN START TO HAPPEN ON THE GROUND AS WE NOTICED ON OUR INITIAL FLIGHT OVER THE AREA.

FOSSILS ARE FOUND IN A LIMESTONE ROCK, A ROCK TYPE THAT MAY SLOWLY START TO DISSOLVE AWAY AS WATER PASSES THROUGH IT OVER TIME.

(DYLAN) AS WATER FILTERS THROUGH THIS IT'LL ACTUALLY DISSOLVE PART OF THE ROCK AND OVER TIME THOSE CRACKS START TO GET BIGGER AND BIGGER BECAUSE WE'RE DISSOLVING MORE AND MORE OF THAT ROCK AND SO WHAT HAPPENS IS WE CREATE THESE CAVERNS WITHIN THE ROCK.

(ROB) THAT IS A SINKHOLE RIGHT THERE.

THAT'S A SINKHOLE.

ALL THOSE, THOSE ARE SINKHOLES.

ANY TIME YOU SEE LITTLE PATCHES OF TREES, THAT'S PRETTY MUCH A SINKHOLE.

LIKE THIS RIGHT HERE, RIGHT NEXT TO THE ROAD.

THAT'S A SINKHOLE.

RIGHT NEXT TO THE CEMETERY WOW THIS WHOLE LANDSCAPE IS JUST DOTTED WITH THESE LITTLE PATCHES OF TREES AND WHEN YOU GET UP TO THE LITTLE PATCHES OF TREES YOU REALIZE THAT IT GOES STRAIGHT DOWN.

(DYLAN) A SINKHOLE WOULD BE SORT OF A BIG ROOM OR A BIG CAVERN THAT WOULD FORM AND AS IT DISSOLVES - AS THAT ROCK DISSOLVES- AND WE START TO GET THINNER AND THINNER.

THE LAYER UP ABOVE IT- THAT LAYER, THAT TOP LAYER- CAN THEN COLLAPSE.

RIGHT AND SO THEN WE HAVE THE SURFACE LAYER COLLAPSE INTO THE SUB LAYER CREATING ONE OF THESE SINKHOLES.

(ROB) I'M RIGHT OVER THE TOP OF THIS SINKHOLE.

LOOK HOW DEEP IT IS.

YEAH THAT'S THE TOP.

THAT'S THE TOP OF THE TREES IN THAT HOLE.

WHO WOULD HAVE THOUGHT THAT THERE IS A SINKHOLE CAPITAL AND WE'RE IN IT RIGHT NOW.

FOUNTAIN, MINNESOTA: SINKHOLE CAPITAL OF THE USA.

WHY ARE THE SINKHOLES HERE AND NOT OTHER PLACES?

(TIM) WELL THEY'RE MUCH MORE PROMINENT IN THIS FOUNTAIN AREA HERE BECAUSE THAT LIMESTONE THAT SLOWLY DISSOLVES IS VERY CLOSE TO THE SURFACE AND IT'S NOT PROTECTED BY MUCH SOIL.

SO IT'S VERY EASY FOR THE RAIN WATER, SURFACE WATER WHICH IS WEAKLY ACIDIC TO COME IN CONTACT WITH THE LIMESTONE AND START TO DISSOLVE IT.

THERE ARE ALSO PARTS OF THE DRIFTLESS WHERE YOU DON'T FIND MANY SINKHOLES BECAUSE THERE'S ANOTHER LAYER OF ROCK OVER THE TOP OF THE LIMESTONE AND THAT SOMETIMES CAPS THE SURFACE.

(JONAS) WE SOMETIMES HAVE A TENDENCY TO FORGET THAT THERE COULD BE A LOT OF THINGS GOING ON UNDER OUR FEET WITHOUT OUR KNOWLEDGE.

THIS REGION IS PROOF OF THAT.

WHO KNOWS HOW MANY OF THESE SINKHOLES THAT ARE CONNECTED UNDERGROUND AND HOW MANY MORE THAT ARE GOING TO OPEN UP IN THE FUTURE.

(ROB) 1 2 3 4 5 6 7 8 9 10 11 12 13 14- THEY'RE JUST LIKE ALL OVER THE PLACE.

(JONAS) WE PROBABLY WOULDN'T EVEN HAVE KNOWN THAT THERE WERE GIANT UNDERGROUND CAVITIES LIKE THIS IF THE DISSOLVED LIMESTONE HAD NOT BEEN SO CLOSE TO THE SURFACE AS IT IS HERE IN FOUNTAIN.

BUT SINKHOLES EXIST IN OTHER PARTS OF THE DRIFTLESS AS WELL.

WE HAVE BEEN TOLD ABOUT A SPECIAL ONE HIDDEN AWAY IN THE FOREST.

(ROB) THE ENTIRE THING IS FULL OF VICIOUS PLANTS NETTLE, NETTLE, NETTLE.

(JONAS) WE'RE ACTUALLY GOING TO THE TOP OF THE BLUFF.

(ROB) THIS SINKHOLE IS ACTUALLY ON PRIVATE LAND SO WE CAN'T REALLY SHOW WHERE WE ARE BUT I CAN TELL YOU IT'S UP AT THE TOP OF THIS HILL.

IT'S VERY STEEP.

WOW, LOOK AT THIS.

(JONAS) THIS IS SO DIFFERENT TO THE OTHER ONES WE'VE SEEN.

YOU CAN STILL SEE THE KIND OF ALMOST CUP SHAPED GROUND.

HOW EVERYTHING IS KIND OF SUNK IN.

BUT IN CONTRAST TO THE OTHER ONES THAT WE'VE SEEN, THIS IS ACTUALLY GOING INTO A CAVE THIS TIME WE'RE BEING GUIDED BY BUZZ BOCHER, WHO IS A RETIRED ENVIRONMENTAL STUDIES INSTRUCTOR AND KNOWS THIS SINKHOLE CAVE INSIDE OUT.

(BUZZ) IF YOU'RE HAVING A PANIC ATTACK, YOU NEED TO TELL SOMEBODY.

(ROB) SO IT'S TIGHT.

(BUZZ) OH YEAH.

THERE'S SOME REALLY REALLY TIGHT SPOTS.

(ROB) LIKE BY REALLY TIGHT, YOU MEAN LIKE JOIN YOUR HANDS- (BUZZ) YOU HAVE TO PUT YOUR HANDS IN FRONT OF YOU AND WIGGLE THROUGH.

YEAH IF YOU WERE WEARING A HELMET, YOU'D HAVE TO TAKE THE HELMET OFF ‘CAUSE THE HELMET WOULDN'T FIT.

(JONAS) AS WE DESCEND INTO THE CAVE, WE IMMEDIATELY ENTERED THE BIG MAIN CHAMBER THAT LIES JUST A COUPLE OF FEET BELOW THE SURFACE.

THIS HOLLOWED-OUT CAVERN IS ULTIMATELY WHAT CAUSED THE GROUND TO COLLAPSE AND EXPOSE THIS SINKHOLE.

SEEING THE SINKHOLE FROM THIS SIDE ADDS A WHOLE NEW PERSPECTIVE AND UNDERSTANDING TO WHAT WE SAW EARLIER, BUT ALREADY AT THE BACK OF THE MAIN CHAMBER THINGS STARTED TO GET TIGHTER.

(ROB) JUST TRYING TO GET A FEEL FOR WHERE MY LEGS ARE AND IF I CAN GET IN.

(JONAS) IN THE SO-CALLED BIRTH CANAL, MARKS THE BEGINNING OF WHERE THE WATER DRAINS OUT OF THE LARGE SINKHOLE CAVERN AND A COMMON PLACE FOR CLAUSTROPHOBIA TO KICK IN.

TIM IS STARTING TO HAVE BAD FLASHBACKS FROM AN EARLIER VISIT.

(TIM) I'M SERIOUS.

NOBODY CRACK JOKES ABOUT THE TIGHTNESS OF THIS THING.

I'M SERIOUS.

JUST- I'M CHILL AND I WANT TO STAY CHILL.

(JONAS) THIS IS AS FAR AS WE CAN MAKE IT THIS TIME, BUT THE TUNNEL SYSTEM CONTINUES.

WE'RE TOLD THAT OTHER CAVERS HAVE MADE IT ALMOST THREE TIMES AS FAR IN THE PAST.

THIS IMPRESSIVE SINKHOLE CAVE HAS GIVEN US A GLIMPSE INTO THE UNDERGROUND ACTIVITY OF THE DRIFTLESS BUT IT'S ONLY THE BEGINNING AS SINKHOLES ARE NOT THE ONLY WAY INTO THIS HIDDEN WORLD.

(♪ ) IN THE FALL OF 1967, CAVE EXPLORERS STEVE BARNETT AND DAVE JANO ARE ABOUT TO MAKE AN INCREDIBLE DISCOVERY AND UNCOVER ONE OF THE BIGGEST AND MOST IMPRESSIVE HIDDEN SECRETS OF THE DRIFTLESS REGION.

BARNETT HAD SCOUTED THE LOCATION BEFORE FREE DIVING THE 47 DEGREE WATER, HE FOUND THAT THE SPRING AT THE BASE OF THE BLUFF SEEMED TO BE THE OUTFLOW OF A POTENTIAL CAVE SYSTEM.

THE TWO HAD BEEN INVESTIGATING SPRINGS ALL OVER NORTHEAST IOWA WITH HOPES OF FINDING UNDISCOVERED CAVES.

THE VOLUME OF WATER AT THIS SPRING SHOWED POTENTIAL OF A GOOD-SIZED TUNNEL INSIDE.

AT THIS POINT, THE TWO HAD NO IDEA THAT THE CAVE SYSTEM THEY WERE ABOUT TO ENTER WITHIN THE NEXT COUPLE OF YEARS TAKE THEM MILES UNDERGROUND UNDER THE IOWA FARMLANDS.

THIS IS WHAT THE LAND LOOKS LIKE ONLY A COUPLE OF MILES FROM THE SPRING.

TOOK A WHILE FOR US TO FIND THIS BECAUSE THIS IS RIGHT IN THE MIDDLE OF KIND OF NOWHERE.

IN THE MIDDLE OF A FIELD, JUST LIKE A BUNCH OF TREES RIGHT HERE, (ROB) ALL RIGHT, SO LET ME JUST FILL YOU IN ON WHAT WE'RE DOING.

THIS LITTLE STRUCTURE BEHIND US IS WHERE THE ENTRANCE TO THE CAVE IS.

IT GOES DOWN ALMOST A HUNDRED FEET.

(♪ ) (JONAS) TO THIS DATE, NO NATURAL SURFACE ENTRANCE TO THIS CAVE HAS BEEN FOUND AND THE SPRING RESURGENCE HAS BEEN GATED OFF FOR SAFETY REASONS.

THE ONLY WAY TO GET TO THE CAVE SYSTEM TODAY IS HERE.

(♪ ) (GEORGE) SEE YOU DOWN BELOW GUYS.

(♪ ) (JONAS) AT SOME POINT, SO YOU DRILLED THIS HOLE DOWN.

SOMEHOW THEY HAD FIGURED OUT THE DOWN HERE IS THE BEST PLACE TO ACTUALLY GET TO THE CAVE SYSTEM.

THE SINKHOLE CAVE GAVE US AN IDEA WHAT WAS GOING ON, BUT THIS IS JUST INCREDIBLE.

WE'RE STANDING IN AN UNDERGROUND RIVER RUNNING THROUGH A TUNNEL LARGE ENOUGH TO FIT A TRAIN.

AND WE'RE LUCKY THERE HASN'T BEEN A WHOLE LOT OF RAIN LATELY SO THE WATER'S WAIST-DEEP AT MOST.

(ROB) BASICALLY WE'RE TRYING TO TRAVERSE BACK INTO THIS CAVE AND IT'S TRICKY BECAUSE EVERY STEP IS DIFFERENT.

(GEORGE) THE BIGGEST HAZARD IS TRIPPING SO JUST GO REALLY SLOW.

TRY NOT TO DUMP THE CAMERAS.

OH THAT'S GONNA BE COOL (JONAS) HOLD IT AT 3 2 1.

THE TUNNEL ALMOST LOOKS DUG OUT BUT NO HUMAN HAS HAD ANYTHING TO DO WITH MAKING THIS.

ONLY WATER SLOWLY OVER TIME, ERODING AWAY THE LIMESTONE SEDIMENTARY ROCK AND CREATING A NETWORK OF TUNNELS AND PASSAGEWAYS.

IN SEVERAL PLACES WE CAN SEE HOW WATER IS LITERALLY COMING OUT OF THE ROCK AND FEEDING MORE WATER TO THE UNDERGROUND RIVER.

AND JUST A SHORT WALK UPSTREAM, WE COME ACROSS A WHOLE ROCK COVERED IN FOSSILS.

THESE ARE CRINOIDS: ANCIENT SEA LILIES.

RELATIVES OF TODAY'S SEA STARS.

THESE WERE COMMON IN THE SUBTROPICAL SEA THAT COVERED THIS PART OF THE PLANET AROUND 300 TO 500 MILLION YEARS AGO.

(ROB) YEP.

CLEAR.

(JONAS) AND EVEN IF IT FEELS LIKE WE'VE SEEN A LOT ON THIS VISIT, IT'S ONLY A SMALL PART OF THE MORE THAN 17 MILES OF TUNNELS THAT HAVE BEEN EXPLORED SO FAR.

I JUST WANT TO REMIND EVERYONE WHAT WE'RE ACTUALLY STANDING ON HERE.

CHECK THIS OUT.

17 MILES OF TUNNELS UNDER THIS.

(♪ ) (JORDAN) HAVING SEEN THIS SPRING RESURGENCE AND KNOWING WHAT IT IS LIKE INSIDE THIS CAVE.

HOW VAST, HOW BEAUTIFUL THE FORMATIONS.

WHENEVER I SEE ANOTHER SPRING, I HAVE THE SAME THOUGHTS AND VISUAL EMOTIONS THAT COME AND JUST FLOOD ME WITH WHAT IS THAT CAVE SYSTEM LIKE?

THERE ARE A LOT OF CAVES SPRING RESURGENCES IN THE AREA, SOME OF THEM WITH HIGHER FLOW RATES OF WATER THAT ARE EXITING OUT AND THAT ONLY LEADS YOU TO BELIEVE THAT THE CAVE SYSTEM IS EVEN LARGER THAN THIS CAVE SYSTEM AND THIS ONE IS ALREADY AT 17.2 MILES SO FAR.

(JONAS) THE INTERACTIONS BETWEEN THE UNIQUE GEOLOGY AND WATER HAVE UNDOUBTEDLY GIVEN RISE TO MANY HIDDEN MYSTERIES IN THE DRIFTLESS REGION AND THERE ARE LIKELY MANY MORE THAT ARE YET TO BE DISCOVERED.

WHAT IS EVEN MORE INTERESTING IS HOW THIS SUBTERRANEAN NETWORK OF CRACKS AND TUNNELS CONTINUES TO SHAPE THE REGION ALSO ON THE OUTSIDE.

AS IT TAKES SEVERAL YEARS FOR THE WATER TO FILTER THROUGH THE SEDIMENTARY ROCK, THE TEMPERATURE OF THE SPRINGS THAT EVENTUALLY EXIT THE BLUFFS STAY COOL ALL YEAR-ROUND.

AND HAS GIVEN RISE TO RICH AND DIVERSE ABUNDANCE OF WILDLIFE.

ONE EXAMPLE IS THE NATIVE BROOK TROUT WHICH IS A SPECIES THAT DEPENDS ON COLD AND CLEAN WATER TO SURVIVE AND THIS IS AN AREA WHERE THEY THRIVE.

THE DRIFTLESS IS TODAY ONE OF THE BEST TROUT FISHING DESTINATIONS IN THE COUNTRY AND IT HAS THE HIGHEST DENSITY OF COLDWATER STREAMS IN THE WORLD.

THE SPRINGS AND RAIN WATER GROWS INTO STREAMS AND EVENTUALLY LARGE RIVERS AND JUST LIKE UNDERGROUND AS THE WATER MOVES OVER THE LANDSCAPE IT SLOWLY EATS ITS WAY INTO THE LOOSE SEDIMENTARY ROCK LAYERS.

IT IS THIS PROCESS THAT OVER A FEW MILLION YEARS HAS CREATED THE DRIFTLESS AND THE BLUFFS AS WE SEE THEM TODAY.

(DYLAN) WHEN YOU'RE LOOKING AT A MOUNTAIN IS USUALLY AN UPLIFT EVENT THAT FORCED THE THE LANDSCAPE UPWARDS.

HERE, WE HAD SEVERAL EROSION EVENTS THAT CARVE THE RIVER CHANNEL WITHIN THE SURROUNDING LANDSCAPE SO WE HAVE WHAT WE CALL INVERSE TOPOGRAPHY.

(JONAS) THIS IS THE EXPLANATION TO WHY ALL THE BLUFFS ARE THE EXACT SAME HEIGHT.

(ROB) THE BLUFFS LOOK TOTALLY DIFFERENT FROM HERE.

THEY'RE ALL ABOUT THE SAME HEIGHT.

(JONAS) THE TOP OF THE BLUFFS IS SIMPLY THE BASELINE WHERE EVERYTHING WAS AT SOME POINT AND ANYTHING BELOW IS WHAT HAS BEEN CARVED OUT AND REMOVED THROUGH EROSION.

(DYLAN) BY THAT PROCESS OF CHEMICALLY DISSOLVING MATERIALS AND PHYSICALLY ERODING PICKING OUT MATERIALS AND TRANSPORTING THAT, YOU ULTIMATELY GO FROM HAVING THIS RELATIVELY FLAT SEDIMENTARY ROCK TO HAVING A LANDSCAPE THAT HAS BEEN CARVED UP AND HAS THIS DENDRITIC PATTERN OF STREAMS THAT ARE FOUND ALL ACROSS IT.

(JONAS) THIS SO-CALLED STREAM DISSECTED LANDSCAPE IS WHAT STANDS OUT FROM SURROUNDING AREAS WHERE GLACIERS WIPED THE SLATE CLEAN.

BUT IN SOME RARE PLACES IT IS NOT THE WATER THAT COMES OUT OF THE BLUFFS THAT CREATES A UNIQUE ECOSYSTEM, INSTEAD IT'S THE AIR.

GEORGE AND TIM ARE TAKING US TO A SPOT IN THE FOREST THAT QUITE HONESTLY IS A BEAST TO FIND.

(ROB) NOW ON THE WAY TO HIKE.

INTO THE WOODS!

(GEORGE) I WAS GONNA GO THIS WAY TODAY BUT THIS IS A JUNGLE SO LET'S HEAD UP THE BLUFF.

(JONAS) WE'RE LOOKING FOR A STRANGE AND RARE HABITAT CALLED ALGIFIC TALUS SLOPE.

(ROB) DID YOU FIND IT?

(JONAS) HELLO?

(ROB) HE SAID HE FOUND IT!

TIM FOUND IT!

FINALLY FOUND IT.

THIS IS THE ALGIFIC TALUS SLOPES.

(GEORGE) WE WANT TO BE CAREFUL NOT TO WALK OVER HERE BECAUSE THIS IS A VERY FRAGILE GEOLOGY.

THERE'S ALL THIS FRACTURED ROCK UNDER HERE THAT THE COLD AIR MOVES THROUGH THE BLUFF IS ACTUALLY BREATHING HERE.

THERE'S AIR BEING TAKEN IN A VENT PROBABLY 200 FEET UPHILL.

BUT THERE ARE PLACES IN THIS BLUFF WHERE THERE'S ICE FROM LAST WINTER.

(JONAS) LET'S TRY AND EXPLAIN THIS.

ALGIFIC MEANS COLD PRODUCING AN TALUS IS A WORD FOR THE BROKEN ROCK FRAGMENTS THAT MAKE UP THE UPPER LAYER OF THIS SOIL.

INSIDE OF THESE BLUFFS IT CAN GET VERY COLD.

WATER THAT FLOWS THROUGH THE LIMESTONE IN THE WINTER FREEZES AND CAN FORM ICE CAVES THAT MAY STAY FROZEN ALL YEAR ROUND.

AIR GETS COOLED DOWN BY THIS FROZEN UNDERGROUND WORLD AND GETS DIVERTED OUT OF THE BLUFF THROUGH VENTS IN THE LIMESTONE.

THIS IN TURN GENERATES A PRESSURE GRADIENT THAT STARTS WITH AIR BEING SUCKED IN THROUGH THE VENTS ON TOP OF THE BLUFF DOWN TO THE ICE CAVES WHERE IT GETS COOLED DOWN AND THEN PUSHED OUT THROUGH THE TALUS SLOPE VENTS.

YEAH THIS IS KIND OF WHAT IT FEELS LIKE.

IF I WAS TO SIT DOWN HERE.

RIGHT HERE.

IT'S LIKE I'M GETTING HIT WITH AN AIR CONDITIONER.

IT IS SUCH AN INCREDIBLY DISTINCT TEMPERATURE DIFFERENCE.

JUST FROM STANDING UP TO SITTING DOWN.

(GEORGE) SO I HAVE A THERMOMETER.

I PUT IN THE SLOPE HERE A LITTLE WHILE AGO AND LET'S CHECK IT.

OH MY GOD.

IT'S BELOW FREEZING.

THIS THERMOMETER IS AT 25 DEGREES.

YES.

COME AND LOOK JONAS.

THERE.

32 DEGREES AND IT'S DOWN AT LIKE 24.

OKAY AND IT'S RISING FAST AS I BRING IT OUT.

NOW IT'S GOING BACK UP TO FREEZING.

BUT IT WAS IT WAS ALMOST DOWN TO 20 WHEN I HAD IT DOWN HERE IN THE VENT.

(JONAS) 2O FAHRENHEIGHT, - 5.

CENTIGRADE FOR US EUROPEANS.

IT'S IMPRESSIVE.

ALGIFIC TALUS LOPES ONLY EXISTS HERE IN THE DRIFTLESS REGION AND ONE OTHER PLACE IN WEST VIRGINIA.

IT IS HARD TO THINK THAT ANY PLANTS WOULD THRIVE UNDER THESE CONDITIONS.

BUT THERE ARE SOME EXCEPTIONS.

LIKE THE BEAUTIFUL NORTHERN MONKSHOOD.

THIS RARE FLOWER HAS ADAPTED TO LIVE IN THE COLD AND FRAGILE SOILS OF THESE ALGIFIC TALUS SLOPES.

IN ADDITION TO THE RARE PLANTS THEY'RE ALSO A WHOLE COLLECTION OF RARE SNAILS FOUND ONLY HERE.

PLEISTOCENE RELICS SO TO SPEAK.

BOTH THE PLEISTOCENE SNAILS AND NORTHERN MONKSHOOD ARE LISTED AS FEDERALLY ENDANGERED.

THE CASUAL OBSERVER THOUGH MIGHT NOT REALIZE HOW RARE THEY ARE BUT WE'RE BASICALLY SEEING ICE AGE HOLDOVERS.

(TIM) YOU COME HERE YOU CAN SEE THE PLANTS, THE NORTHERN MONKSHOOD, AND OTHER PLANTS ACTUALLY QUIVERING BECAUSE THIS COLD AIR IS IS POURING OUT OF THE SIDE OF THE HILL THROUGH THESE VENTS.

AND SO THE LEAVES ARE JUST QUIVERING AWAY.

IT'S REALLY WILD.

(JONAS) I THINK IF I WAS TO JUST WALK THROUGH THIS FOREST NOT KNOWING ANYTHING ABOUT THIS I PROBABLY WOULDN'T HAVE YOU KNOW PAID TOO MUCH ATTENTION TO IT EXCEPT FOR THESE BEAUTIFUL,PURPLE FLOWERS.

I WOULD NOT HAVE REALIZED HOW RARE THEY ARE.

I WOULD NOT HAVE REALIZED HOW SENSITIVE THIS WHOLE AREA IS BUT IT IS KNOWING A LITTLE BIT ABOUT THIS MAKES IT IT MAKES IT REALLY SPECIAL TO GET HERE.

(GEORGE) SO THIS ALGIFIC TALUS SLOPE IS YET ANOTHER EXAMPLE OF HOW THE UNIQUE GEOLOGY HERE IN THE DRIFTLESS REGION CREATES THESE NATURAL COMMUNITIES THAT ARE INCREDIBLY RARE.

IF WE DIDN'T HAVE THE SEDIMENTARY ROCK LAYERS IN THE SEQUENCE THEY ARE AND IF WE DIDN'T HAVE TWO MILLION YEARS OF STREAMS CUTTING DOWN THROUGH THIS ROCK TO CREATE A VALLEY AND THEN THE GLACIERS MISSING ALL THIS TO LEAVE IT HERE, WE WOULDN'T HAVE ALGIFIC TALUS SLOPES.

WITH THE BLUFFS ACTUALLY BREATHING AIR IN THE MIDDLE OF SUMMER JUST A LITTLE OVER 20 DEGREES FAHRENHEIT.

(JONAS) AS MUCH AS THESE HABITATS ARE UNIQUE BECAUSE THEY'RE COLD.

THE OPPOSITE ALSO EXISTS.

WE REMEMBERED A STRANGE OBSERVATION WE MADE FROM THE AIRPLANE.

ON SEVERAL OF THE STEEP BLUFF SLOPES THERE WERE EXPOSED PATCHES OF WHAT LOOKED LIKE CLEAR-CUT FORESTS.

BUT CONTRARY TO THE HIDDEN ALGIFIC TALUS SLOPES, THIS AREA SEEMED TO BAKE IN SUNLIGHT.

SO WE TOOK TO THE GROUND WITH LOCAL EXPERTS SCOTTY LEDDY AND KAITLYN O'CONNOR.

IT TURNS OUT THESE CLEAR PATCHES ARE ACTUALLY NOT CLEARED AT ALL.

INSTEAD THEY'RE ANOTHER NATURAL YET SOMEWHAT ODD HABITAT.

THE BLUFF PRAIRIES AND KNOWN BY MANY LOCALS AS GOAT PRAIRIES.

SIMILAR TO THE ALGIFIC TALUS SLOPES, THEY'RE ALSO HOME TO SOME VERY INTERESTING WILDLIFE.

(KAITLYN) OFTENTIMES WHEN YOU'RE JUST DRIVING THROUGH THE DRIFTLESS AND YOU LOOK AT THE BLUFF LAND REGIONS GOAT PRAIRIES KIND OF LOOK LIKE BALD SPOTS IN AN OTHERWISE FORESTED HABITAT.

BUT THESE BALD SPOTS ARE VERY ECOLOGICALLY UNIQUE.

THERE'S A COUPLE OF CHARACTERISTICS THAT DEFINE THE GOAT PRAIRIES AND THE MOST IMPORTANT ONE BEING THE ASPECT OR THE DIRECTION THAT THESE PRAIRIES FACE.

SO YOU'RE ONLY GOING TO FIND GOAT PRAIRIES ON SOUTHERN AND WESTERN SLOPES ON THE BLUFFS.

THE SECOND CHARACTERISTIC IS REALLY SHALLOW ROCKY SOILS.

IN THE SUMMERTIME THE SUN BEATS DOWN AND IT MAKES IT VERY HOT AND VERY DRY.

SIMILARLY IN THE WINTERTIME THE SUN IS GOING TO BEAT DOWN AND IT MELTS THE SNOW OFF OF THESE STEEP SLOPES AND IT MAKES THIS AREA EXPOSED TO THE VERY HARSH WINTER CONDITIONS THAT WE HAVE UP IN THE DRIFTLESS REGION.

SO ANYTHING THAT THRIVES HERE IS IS A REALLY TOUGH COOKIE.

THEY'RE ADAPTED TO VERY HARSH CONDITIONS.

(JONAS) NOT ONLY ARE THE BLUFF PRAIRIES HOME TO HUNDREDS OF SPECIES OF PLANTS, THIS HOT AND DRY HABITAT IS ALSO PERFECT FOR SOME OTHER RARE SPECIES.

MOST PEOPLE WOULD NOT ASSOCIATE RATTLESNAKES WITH MINNESOTA BUT EVEN IF THEY ARE HARD TO FIND THE STEEP BLUFFS ARE IN FACT HOME TO A POPULATION OF TIMBER RATTLESNAKES.

THIS IS OBVIOUSLY A GREAT SIGN THAT THEY ARE HERE.

SO LET'S SEE IF WE CAN ACTUALLY FIND A LIVE ONE.

I'M GONNA PUT THIS ONE BACK WHERE I FOUND IT.

BUT AS THEY ARE VERY WELL CAMOUFLAGED FINDING ONE REQUIRES SOME WORK.

AND AS THE SUN STARTED TO HEAT UP THE ROCKS WE GOT LUCKY.

THERE'S ONE IN THAT BUSH.

THERE'S A SECOND ONE.

IT RATTLED AT ME.

AND IT'S RIGHT NOW, OUT THERE.

TIMBER RATTLESNAKES ARE GENERALLY FOUND MUCH FURTHER SOUTH BUT BECAUSE OF THE UNIQUE HABITAT THIS SOMEWHAT ISOLATED POPULATION STILL REMAINS UP HERE.

TIMBER RATTLESNAKES ARE ACTUALLY QUITE DOCILE AND NOT AGGRESSIVE AT ALL.

UNFORTUNATELY THEIR NUMBERS HAVE DECLINED A LOT MOSTLY DUE TO HABITAT LOSS AND THE GENERAL PUBLIC FEARING THESE ACTUALLY GENTLE SNAKES.

IN THE EARLY 1900'S THIS LED TO A BOUNTY ON TIMBER RATTLESNAKES IN MINNESOTA AND WISCONSIN.

A BOUNTY THAT HAS NOW FORTUNATELY BEEN REPEALED.

NOW WORK IS FOCUSED ON RESTORING THE PRAIRIES SUCH AS THROUGH THE REMOVAL OF INVASIVE SPECIES AND RESTORING FIRES TO THIS HABITAT.

THIS PROVIDES IDEAL PLACES FOR BIRDS LIKE THE MEADOWLARKS, BOBOLINKS, AND HENSLOW SPARROW.

IN ADDITION TO THE AMAZING FLOWERS AND RARE REPTILES, ANOTHER INTERESTING REPTILE THAT LIVES UP HERE IS THE SIX-LINED PRAIRIE RACE RUNNER.

AFTER GETTING HEATED UP THEY'RE EXTREMELY FAST AND VERY SHY.

THE SLIGHTEST MOVEMENT AND THEY'RE GONE.

LUCKILY WE MANAGED TO FIND A COUPLE THAT HAD OTHER THINGS ON THEIR MIND THAN WORRYING ABOUT US.

A RARE THING TO WITNESS FOR SURE.

AS ALL REPTILES THESE SNAKES AND LIZARDS NEED HEAT FROM THE SURROUNDING ENVIRONMENT TO KEEP THEM ACTIVE.

TO SURVIVE WINTERS, THEY LOCATE ROCK CREVICES OR BURROWS BELOW THE FROST LINE AND GO INTO A STATE OF HIBERNATION.

TO CONSERVE HEAT EVEN MORE, SEVERAL SNAKES EVEN DIFFERENT SPECIES OFTEN SHARE WINTER DENS, LIKE THIS MOLTING BULLSNAKE.

AS THE WEATHER WARMS UP IN SPRING AND PROVIDES ENOUGH HEAT THE REPTILES EMERGE FROM THEIR LONG WINTER SLEEP.

BECAUSE OF THE LONG WINTERS UP HERE AND THE ABUNDANCE OF NATURAL DENS BENEATH THE GROUND, THE HABITAT THAT IS FAVORED BEFORE ALL OTHERS BY THESE REPTILES ARE THE HEATED SOUTH-FACING HILLSIDES OF THE BLUFF PRAIRIES.

(SCOTT) YOU KNOW IT'S ALL ABOUT HABITAT.

DON'T HAVE IT AND YOU'VE GOT NOTHING.

IT'S ALL ABOUT PLACES LIKE THIS.

(JONAS) FOR US IT IS ANOTHER EXAMPLE OF HOW THESE BLUFFS PROVIDE UNIQUE OPPORTUNITIES FOR LIFE THIS FAR NORTH THAT OTHERWISE WOULD NOT HAVE BEEN POSSIBLE.

(ERIC) WITH THE CYCLES OF GLACIERS THAT CAME AND WENT, WE'RE ACTUALLY SEEING FEATURES THAT HAVE WITHSTOOD THOSE ICE AGES.

WE'RE SEEING EXAMPLES OF PLACES WHERE THERE'S WHAT WE CALL REFUGIA, WHERE THEY'RE SPECIES THAT LIVED HERE DURING THE COLDER CLIMATE AND THEY'VE ACTUALLY HUNG ON HERE IN LITTLE POCKETS BECAUSE IT IS AN OLD LANDSCAPE AND BECAUSE IT WASN'T OVERRUN BY ICE.

(JONAS) BUT TO CLAIM THAT WE ARE JUST NOW FIGURING THIS OUT AND HOW SPECIAL THIS AREA IS COULDN'T BE MORE WRONG.

THE TRUTH IS THAT THESE BLUFFS WERE THE CAVES AND THE CAVERNS, GREEN VALLEYS, AND COOL FRESHWATER STREAMS HAD BEEN SACRED PLACES FOR HUMANS AND WILDLIFE ALIKE FOR A VERY LONG TIME.

ROCK PAINTINGS HAVE BEEN FOUND IN CAVES DEEP UNDERGROUND AND ROCK SHELTERS BY THE SOFT SEDIMENT BLUFFS DISPLAY ROCK CARVINGS THOUSANDS OF YEARS OLD.

(WILLIAM) IF YOU LOOK AT THE UNDERSIDE OF A HAWK OR AN EAGLE OR OTHER BIRDS OF PREY- IF YOU'VE EVER SEEN THE WAY THAT THEY FAN OUT- PERHAPS THAT'S WHAT YOU HAVE HERE.

AS FOR THE ROCK ART, SPECTACULAR ROCK ART.

WE HAVE BOTH ROCK ART THAT'S BEEN DONE WITH PIGMENTS AS WELL AS ROCK ART THAT'S INCISED INTO THE ROCK ITSELF.

SO WE HAVE DIFFERENT WAYS WE HAVE THESE VERY ELABORATE COMPOSITIONS.

SOME OF WHICH CAN BE LINKED UP TO HO CHUNK ORAL TRADITIONS FOR EXAMPLE.

AND SO THE OVERALL CONTEXT OR PACKAGE IS SOMETHING THAT'S ABSOLUTELY UNIQUE ANYWHERE.

(JONAS) THE HO CHUNK WERE ONE OF THE EARLIER INHABITANTS OF THE AREA AND ONE OF SEVERAL NATIVE AMERICAN TRIBES THAT RESIDED HERE.

THE BLUFFS OF THE DRIFTLESS MADE FOR GREAT NATURAL ROCK SHELTERS, PROTECTING THE EARLY INHABITANTS FROM THE FORCES OF NATURE.

THEIR IMPORTANCE IS DISPLAYED BY THE DIVERSITY AND NUMBER OF ROCK ART FOUND ACROSS THE REGION.

THE SEDIMENTARY SANDSTONE WAS EASY TO CARVE, YET STRONG ENOUGH TO PRESERVE THE ARTWORK GIVING US A GLIMPSE INTO THE CULTURAL HISTORY OF THE AREA.

BUT THE MOST IMPRESSIVE AND MYSTERIOUS REMAINS OF EARLY HUMANS MAY STILL BE THE SEVERAL HUNDREDS OF SO-CALLED EFFIGY MOUNDS FOUND ALL THROUGHOUT THE DRIFTLESS REGION.

FROM ILLINOIS TO MINNESOTA.

(MARK) WE ARE STANDING ON SACRED GROUND.

THIS IS INDISPUTABLE TO ME.

AND IF YOU STAND AT THE HEAD OF THE BIRD MOUND ON THE FIRST DAY OF SPRING, THE VERNAL EQUINOX, AND LOOK TO THE EAST AT SUNRISE, THERE'S A SMALL NOTCH IN THE FAR RIDGE AND THAT'S WHERE THE SUN RISES.

AND IT LOOKS LIKE THIS BIRD IS GIVING BIRTH TO THE SUN.

IT'S AN ABSOLUTELY INCREDIBLE SIGHT.

BUT IF YOU CAN IMAGINE A THOUSAND YEARS AGO IF YOU WERE ON THIS SITE, THERE WOULD HAVE BEEN MANY FEWER TREES AND THERE WOULD HAVE LITERALLY BEEN HUNDREDS OF MOUNDS VISIBLE.

YOU WOULD HAVE PROBABLY SEEN A LARGE CENTRAL VILLAGE SITE, PERHAPS SOME SATELLITE VILLAGE SITES.

SMOKE RISING FROM CAMPFIRES AND THE HUMAN ACTIVITIES GOING ON THAT WOULD HAVE BEEN PART OF DAILY LIFE.

AND IT WOULD HAVE BEEN QUITE AN INCREDIBLE SIGHT TO SEE.

(STEVE) WE KNOW THE EARLIEST PEOPLE IN THIS AREA CAME TO THIS RESOURCE-RICH PART OF THE WORLD.

SO THIS WAS A HABITATION SITE FOR THE EARLIEST AMERICANS.

THINK ABOUT HOW YOU WOULD MOVE ABOUT THE LANDSCAPE WITHOUT VEHICLES OR HORSES OR ANY OTHER WAY TO GET AROUND.

YOU'D BE USING THE CORRIDORS OF THE WATER.

BEING NOMADIC, THEY'RE LOOKING FOR WAYS THAT THEY CAN GET TO PLACES WHERE THERE'S RICH GAME AND RICH LAND IN THE FALL.

AND PROTECTED AREAS IN THE WINTER.

SO A LOT OF THESE RUGGED BLUFFLANDS AND DRIFTLESS AREA PROVIDED BOTH OF THOSE THINGS IN CLOSE PROXIMITY.

(JONAS) THE MOUND BUILDING CULTURES LIVED AROUND A THOUSAND YEARS AGO.

THE PURPOSE AND SHAPE OF THE MOUNDS VARIED.

SOME WERE BUILT AS BURIAL MOUNDS AND OTHERS WERE MADE FOR DIFFERENT CEREMONIAL AND SPIRITUAL PURPOSES.

USING LIDAR TECHNOLOGY A TECHNIQUE OF SCANNING THE GROUND WITH LASER WE NOW KNOW THAT THERE ARE MANY MORE EFFIGY MOUNDS THAN ANYONE EVER KNEW.

IN FACT THERE ARE MORE OF THEM HERE THAN ANYWHERE ELSE IN THE WORLD.

AND BECAUSE OF THAT THE EFFIGY MOUNDS NATIONAL MONUMENT WAS ESTABLISHED HERE IN 1949.

(MARK) YOU HAVE TO RECOGNIZE THAT THE BUILDING MOUNDS IS NOT AN EASY TASK.

YOU HAVE BUFFALO SCAPULA HOES AND REED BASKETS AND IT TAKES A LOT OF CALORIES AND ENERGY TO BUILD A MOUND.

SO YOU HAVE TO HAVE A CHARISMATIC ENOUGH LEADER THAT SAYS WE'RE GONNA BUILD A MOUND TODAY AND THEN YOU HAVE TO HAVE THE BUY-IN FROM THE PUBLIC, OR YOUR PEOPLE.

OK WE'LL BUILD A MOUND.

(ROB) WERE THEY TAKING THAT DIRT FROM HERE AND JUST PUTTING IT THERE OR WERE THEY BRINGING IT FROM DOWN IN THE RIVER VALLEY?

(MARK) IN SOME CASES, THEY WOULD ACTUALLY DIG SUBSURFACE INTO THE SHAPE THEY WERE SEEKING TO IDENTIFY.

AND THEY WOULD LAYER SPECIAL SOILS IN SOME CASES BROUGHT FROM SOME DISTANCES.

IN SOME CASES PERHAPS CLEAN SANDY SOILS FROM SPRINGS.

YOU KNOW YOU GIVE THAT VERY SUGAR-SAND LOOK.

AND IN SOME CASES, THEY WOULD SCRAPE SOIL UP FROM AROUND THE MOUNDS AND IN OTHER CASES THEY MAY INDEED TOTE THEM WITH BASKETS FROM THE NEARBY WETLAND OR WHEREVER.

AND THEN THE ENGINEERING ACUMEN TO SAY A THOUSAND YEARS AFTER THEY'VE BEEN BUILT THEY'RE STILL HERE ON THE LANDSCAPE TELLING US A STORY THAT WE WANT TO KNOW MORE ABOUT.

BUT THEY'RE STILL HERE AS PART OF THEIR CULTURAL LANDSCAPE.

AND THEN OF COURSE THE KNOWLEDGE OF THE SKIES, THE SUN, THE STARS, AND THE MOON, TO HAVE ALIGNMENTS WHERE THOSE ALIGNMENTS DO OCCUR.

IT'S REALLY INCREDIBLE.

(ROB) THAT'S INCREDIBLE.

THANKS FOR SHOWING THIS ALL TO ME.

(JONAS) THAT THE EFFIGY MOUNDS ARE OFTEN MADE IN SHAPES OF SYMBOLIZED ANIMALS.

WHY THERE'S SUCH A HIGH CONCENTRATION OF THEM HERE IS STILL NOT FULLY UNDERSTOOD, BUT MAYBE NOT SO SURPRISING.

THE COMPLEX TOPOGRAPHY AND VEGETATION CONTAIN A RANGE OF HABITATS THAT IN TURN SUPPORT A RICH DIVERSITY OF LIFE.

BUT THE BIG QUESTION IS STILL HOW IT IS POSSIBLE THAT THIS AREA GOT LEFT UNTOUCHED BY THE GLACIERS, ALLOWING THIS COMPLEX TOPOGRAPHY TO REMAIN WHEN EVERYTHING AROUND IT GOT LEVELED.

YEAH THIS IS THE PLACE.

THIS IS A NICE SPOT.

(JONAS) THIS IS DEVIL'S LAKE, ONE OF ONLY TWO LAKES IN THE DRIFTLESS AND A BODY OF WATER CREATED BECAUSE OF THE ADVANCING GLACIERS.

IT ALSO MARKS THE EASTERN EDGE OF THE DRIFTLESS REGION.

AND SO RIGHT HERE THIS IS JUST A REALLY QUIRKY FORTUITOUS PLACE THAT THE ICE CAME FAR ENOUGH, THAT IF YOU LOOK OFF HERE, WE CAN SEE, THE EDGE OF THE DRIFTLESS AREA THERE.

AND THEN IT EXTENDS BEHIND US TO THE WEST ALL THE WAY DOWN TO THE MISSISSIPPI RIVER AND BEYOND.

(JONAS) I THOUGHT ABOUT THIS SO MANY TIMES.

THAT THE GLACIERS MISSED THIS PART OF NORTH AMERICA.

IT IS UNIQUE AND THERE'S DIFFERENT EXPLANATIONS FOR WHY THE ICE STOPPED IN DIFFERENT AREAS.

OFF TO THE WEST THE ICE WAS FLOWING DOWN OUT OF THE CANADIAN ROCKIES.

AND IT FLOWED TO DIFFERENT DISTANCES OVER DIFFERENT ICE AGES.

AND IT'S PARTLY A FUNCTION OF HOW FAR THE ICE WAS ABLE TO FLOW WITH THE SUPPLY OF ICE AND PARTLY IT WAS PROBABLY STEERED BY THE WAY THE BEDROCK OUT CROPS IN IN IOWA IN MINNESOTA.

IF YOU GO TO THE NORTH OF US THE ICE WAS TRYING TO FLOW ACROSS THE LAKE SUPERIOR LOWLAND WHICH IS A TREMENDOUSLY DEEP HOLE IN THE GROUND.

AND SO THAT WAS IN ITSELF JUST A NATURAL IMPEDIMENT TO ICE COMING DOWN TOWARDS THE DRIFTLESS AREA FROM THE NORTH.

AND THEN OFF TO THE EAST OF US THERE'S THE GREEN BAY LOWLAND AND THE LAKE MICHIGAN LOWLAND WHICH ARE TROUGHS THAT ARE ORIENTED NORTH-SOUTH AND KIND OF STEERED THE ICE STRAIGHT TO THE SOUTH OFF TO THE EAST OF US.

AND IN ADDITION THE BEDROCK IN CENTRAL WISCONSIN HAS BOWED UP INTO AN ARCH THAT DEFLECTED THE ICE AROUND THE DRIFTLESS AREA.

AND FARTHER NORTH THE HARD ROUGH CRYSTALLINE ROCK WAS A FURTHER IMPEDIMENT TO STOPPING THE ICE FROM FLOWING ANY FARTHER SOUTH.

CORES SHOW THAT THERE WERE FLUCTUATIONS THAT INDICATE THERE WERE AS MUCH AS A COUPLE DOZEN ICE AGES OVER THE LAST TWO AND A HALF MILLION YEARS.

SO YEAH WHEN WE TALK ABOUT THE ICE AGE WE'RE THINKING OF THE LAST ONE.

BUT THERE WERE A COUPLE DOZEN THAT PRECEDED IT AND ALL OF THEM MISSED THE AREA.

(JONAS) THERE ARE A COUPLE OF IMPORTANT RESULTS FROM THIS WE HAVE ALREADY SAID THAT THE DRIFTLESS EXISTS BECAUSE IT WASN'T COVERED BY GLACIAL ICE.

BUT IT'S NOT EXACTLY RIGHT TO SAY GLACIERS LEFT THE AREA UNTOUCHED.

SIMPLY PUT THE DRIFTLESS REGION IS NOT WHAT IT IS ONLY BECAUSE IT GOT SPARED BY THE GLACIERS, BUT ALSO BECAUSE THERE WERE GLACIERS NEARBY.

AT THE CENTER OF THE WHOLE DRIFTLESS LIKE A MIGHTY ARTERY THROUGH THE REGION CONNECTING THE VEINS OF WATER THAT CARVES THROUGH THE BLUFF LANDSCAPE IS THE MIGHTY MISSISSIPPI RIVER.

(♪ ) JUST LIKE THE REST OF THE LAND THIS WAS ONCE FLAT GROUND COMPOSED OF LAYERS OF ANCIENT MARINE SEDIMENT.

THE HUGE AMOUNT OF MELTWATER COMING FROM NEARBY GLACIERS IS WHAT STARTED THE FORMATION OF THIS IMPRESSIVE RIVER VALLEY.

ROB AND I HAVE HAD A CHANCE TO SEE IT FROM ABOVE SEVERAL TIMES AND EVERY TIME IT'S JUST AS AMAZING.

JUST THE THOUGHT THAT WATER ALONE HAS CARVED ALL THIS OUT IS SOMEWHAT MIND-BLOWING.

THE MISSISSIPPI RIVER WAS IMPORTANT ALREADY TO EARLY SETTLERS USING THE WATERS TO GET AROUND.

AND IT'S JUST AS IMPORTANT TO THE PEOPLE OF THE DRIFTLESS TODAY.

AND THE REST OF THE COUNTRY TOO FOR THAT MATTER.

AS IT IS ONE OF THE LARGEST RIVER SYSTEMS IN THE WORLD CONNECTING THE NORTH OF THE U.S.

WITH THE GULF OF MEXICO.

250 MILES OF THE UPPER MISSISSIPPI RUNS THROUGH THE DRIFTLESS AREA.

BUT THERE'S ALSO BEEN TIMES IN HISTORY WHEN THE RIVER WAS A LOT DEEPER.

GEOLOGISTS HAVE MEASURED THAT THE ACTUAL BOTTOM OF THE RIVER LIES ANOTHER 300 FEET DEEPER THAN THE BOTTOM OF THE RIVER TODAY.

(DYLAN) WHEN THE GLACIERS WERE MELTING AND CARRYING SEDIMENT, THAT SEDIMENT ENDED UP IN THIS RIVER VALLEY.

AND IT ACTUALLY FILLED IT UP TO A LEVEL MUCH HIGHER THAN IT IS RIGHT NOW WITH GLACIAL OUTWASH SEDIMENT.

(JONAS) THE SAME GLACIAL WATER THAT CARVED IT OUT ALSO REFILLED IT WITH MASSIVE AMOUNTS OF SEDIMENT THAT CAME WITH THE WATER.

THE HUGE AMOUNT OF GLACIAL SEDIMENTS ALSO RESULTED IN MAKING THE UPPER MISSISSIPPI UNIQUE IN SOME OTHER RATHER ODD WAYS.

(DYLAN) SO WE'RE AT LAKE PEPIN RIGHT NOW.

IT'S ACTUALLY A REALLY UNIQUE FEATURE BECAUSE IT'S THE WIDEST PART OF THE MISSISSIPPI RIVER AND IT'S ALL NATURAL.

THE LAKES ARE VERY RARE IN THIS AREA.

WELL HERE WE HAVE A NATURAL RIVERINE LAKE.

IT'S BEEN IN EXISTENCE SINCE THE SINCE THE GLACIERS WORK CLOSE BY HERE A LITTLE OVER 10,000 YEARS AGO.

AND WE HAVE THIS NATURAL SYSTEM WHERE THE CHIPPEWA RIVER IS DAMMING THE MISSISSIPPI RIVER CREATING LAKE PEPIN.

AND IT'S A PRETTY RARE RARE AND INTERESTING PHENOMENON.

(JONAS) WE CAN SEE HUGE AMOUNTS OF GLACIAL SEDIMENTS AND SAND THAT ARE STILL PARTIALLY DAMMING UP THE MISSISSIPPI TODAY.

AND FUN FACT IF NONE OF THIS HAD HAPPENED THERE'S A RISK WE WOULDN'T HAVE WATERSKIING TODAY.

(ROB) IT SAYS“LAKE CITY, THE BIRTHPLACE OF WATERSKIING.” WELL WE COULDN'T REALLY PASS THAT UP SO WE GOT TO GET OUT ON THE RIVER.

(♪ ) (JONAS) CAN YOU IMAGINE?

WHO WOULD HAVE GUESSED WE WOULD HAVE THE LAST ICE AGE TO THANK FOR ALL THIS?

NOW THERE'S A FUN FACT TO SHARE AT DINNER TONIGHT.

OKAY SO NOW LET'S GET BACK TO THE MAIN STORY.

(ROB) EVERYBODY IN.

HOPEFULLY WE CAN SEE SOME COOL THINGS WE'RE OUT HERE YOU POINT OUT YOUR FAVORITE BITS.

I'M EXCITED TO JUST BE OUT HERE AND SEE SOME OF THE DIVERSITY IN HABITATS.

(♪ ) (KENDRA) PEOPLE ARE ALREADY SETTING UP FOR THE WEEKEND.

STARTING TO USE THE BEACHES.

THE MISSISSIPPI IS A WETLAND OF INTERNATIONAL IMPORTANCE.

WE CALL "RAMSAR" WETLAND.

SO THAT MEANS GLOBALLY IT'S BEEN RECOGNIZED AS BEING THAT IMPORTANT.

(ROB) REALLY?

(KENDRA) YEP.

(ROB) SO WE'RE IN A NATIONAL WILDLIFE REFUGE RIGHT NOW.

SO WHAT DOES THAT MEAN FOR THE RIVER.

(KENDRA) YEAH WHAT THAT MEANS IS PROTECTION FOR CONSERVATION.

SO REFUGES ARE MANAGED FOR WILDLIFE FIRST.

WE ALSO DO HAVE RECREATION YOU KNOW PEOPLE CAN COME AND FISH AND HUNT BUT PREDOMINANTLY MOST OF WHAT WE'RE DOING OUT HERE IS MANAGING IT FOR WILDLIFE.

(JONAS) THAT ALSO INVOLVES INFORMING THE PUBLIC ABOUT THE SENSITIVE ANIMALS IN THE RESERVE LIKE THE MANY SPECIES OF TURTLES THAT COME AND NEST ON THE SANDY BEACHES.

(ROB) COME ON UP HERE.

OH IT'S HOT!

OH!

OW THAT'S HOT!

YOU CAN SEE ALL OF THE EGGS THOUGH.

RIGHT HERE.

THEY'VE BEEN PREDATED.

EATEN BY SOMETHING.

WHAT DO YOU THINK ATE THESE THINGS?

SNAKES OR RACCOONS?

ONE THING YOU YOU CAN ACTUALLY SEE RIGHT AT THE MOMENT THOUGH AS YOU CAN SEE THE DUG OUT NEST AND THEN AND OCCASIONALLY YOU CAN SEE THE SLIDE MARKS OF THE TURTLES COMING BACK DOWN.

(JONAS) BUT THE MAIN ATTRACTION WHEN IT COMES TO VIEWING WILDLIFE HERE MUST BE THE BIRDS.

(ROB) OH MY GOODNESS!

LOOK AT THAT, WE'RE SO CLOSE.

I'VE NEVER BEEN THAT CLOSE TO TO A FALCON BEFORE.

(JONAS) THIS IS FOR EXAMPLE, THE SUMMER DESTINATION FOR OVER A HUNDRED SPECIES OF MIGRATORY NEOTROPICAL SONGBIRDS.

LIKE THE CHESTNUT-SIDED WARBLER, NORTHERN PAULA, AND AMERICAN GOLDFINCHES.

WINTERS ARE SPENT FURTHER SOUTH BUT IN THE SUMMER THEY COME UP HERE TO NEST AND BREED.

IN ADDITION THE MISSISSIPPI RIVER IS ALSO A MAJOR FLYWAY FOR MIGRATORY BIRDS.

THAT MEANS THE RIVER FUNCTIONS AS A GUIDANCE FOR THE AERIAL HIGHWAY USED BY MILLIONS OF BIRDS ON THEIR WAY BETWEEN SUMMER NESTING GROUNDS IN NORTHERN CANADA AND THE SOUTHERN PARTS OF THE FLYWAY WHERE THEY SPEND WINTER.

IN FACT MORE THAN 320 BIRD SPECIES HAVE BEEN RECORDED USING THE MISSISSIPPI FLYWAY EACH YEAR.

IT IS NOW MID-JUNE WHICH MEANS RIGHT IN BETWEEN MIGRATION TIMES.

NOW LET'S FAST-FORWARD SIX MONTHS.

(♪ ) IT IS SAID THAT OVER 40% OF THE TOTAL POPULATION OF WATERFOWL IN THE U.S.

PASSED THROUGH THIS MIGRATORY FLYWAY.

DURING PEAK MIGRATION HUNDREDS OF THOUSANDS OF TUNDRA SWANS AND OTHER WATERFOWL CAN BE SEEN FEEDING AND RESTING IN THE POOLS OF THE RESERVE.

AND THE ABUNDANCE OF FOOD HERE MAKES IT A GIVEN STOPOVER.

AS A PHOTOGRAPHER VIDEOGRAPHER THIS IS SOMETHING YOU'VE GOT A DREAM ABOUT.

YOU'RE SURROUNDED BY THIS ENVIRONMENT, THE COLORS OF THE BLUFFS, THE WHITE SWANS, THE CONTRASTS OF WATER.

THIS IS WHY I BECAME A WILDLIFE FILMMAKER, PHOTOGRAPHER.

(THOMAS) THE DRIFTLESS AREA IS AN EXTREMELY UNIQUE AREA AND BIRDWATCHERS HAVE TAKEN NOTE FROM ALL OVER THE COUNTRY AND EVEN THE WORLD.

BIRD WATCHERS LOVE TO KEEP A LIFE LIST WHERE THEY KEEP TRACK OF HOW MANY DIFFERENT SPECIES THEY'VE SEEN KIND OF CHECKING OFF EACH SPECIES AND THE DRIFTLESS AREA IS A GREAT PLACE FOR BIRD WATCHERS THAT COME TO SEE A VARIETY OF SPECIES IN WINTER, SPRING, SUMMER, AND FALL.

(JONAS) I REALIZE IT MAY LOOK LIKE WE'RE PAINTING A PICTURE OF A WILDLIFE REFUGE FREE FROM PROBLEMS, BUT THE REALITY IS NOT THAT EASY AND IT'S NOT WITHOUT HELP.

FOR EXAMPLE, PROGRAMS LIKE THE DRIFTLESS AREA TROUT UNLIMITED RESTORATION EFFORTS ARE WORKING TO RESTORE COLDWATER SPRINGS DAMAGED BY EROSION.

(DUKE) WHERE WE CAN DO RESTORATION, WE CAN REALLY RESTORE THEM TO SOMETHING THAT IS REALLY RARE IN THE WORLD.

(JONAS) BLUFF PRAIRIES HAVE BEEN DISAPPEARING DUE TO LACK OF WILDFIRES AND THE INTRODUCTION OF INVASIVE SPECIES.

THROUGH PRESCRIBED BURNS AND THE REMOVAL OF NON-NATIVE VEGETATION, GROUPS LIKE THE PRAIRIE ENTHUSIASTS HAVE MANAGED TO RESTORE AND PROTECT A LOT OF THIS RARE HABITAT, ALLOWING SOME OF THE UNIQUE BIODIVERSITY TO REMAIN.

AND EVEN PRIVATE LANDOWNERS ARE SIGNING UP TO PROTECT THEIR LAND FROM FURTHER DEVELOPMENT.

(MICHAEL) WE FEEL STRONGLY THAT WE WANT TO BE GOOD STEWARDS OF THE LAND.

AND THERE'S FEATURES ON THIS LAND RANGING FROM ROCK ART THAT'S UP TO 2,000 YEARS OLD TO VIRGIN RED OAK FORESTS.

AND WE WOULDN'T EVER WANT TO SEE THAT DEVELOPED.

SO WE WANT TO PROTECT IT.

(JONAS) UNIQUE HABITATS ARE OFTEN ALSO SENSITIVE TO CHANGE, WHETHER IT BE CHANGING CLIMATES, NEW DEVELOPMENTS, OR THINGS WE DO THAT AFFECT THE ENVIRONMENT EVEN IF OUR INITIAL INTENTIONS WERE GOOD.

THE STORY OF THE PEREGRINE FALCON IS ONE EXAMPLE.

THESE TOP OF THE FOOD CHAIN PREDATORS ARE THE FASTEST ANIMALS ON THE PLANET.

NESTING ON THE STEEP BLUFF SITES, PEREGRINE FALCONS HAVE HAD A GREAT SYMBOLIC IMPORTANCE TO THE DRIFTLESS FOR THOUSANDS OF YEARS.

BUT RECENTLY ALMOST DISAPPEARED COMPLETELY.

(STATIC) THE GREATEST POTENIALITY OF DDT LIES IN DISPERSAL FROM PLANES.

(JONAS) THE USE OF THE PESTICIDE DDT THAT WAS DEVELOPED IN THE 1940S TO HELP FIGHT THE SPREAD OF DISEASES LIKE MALARIA AND TYPHUS, ALMOST CAUSED THEM AND OTHER RAPTORS LIKE THE BALD EAGLE TO GO EXTINCT FROM THE AMERICAN CONTINENT.

AND THE DRIFTLESS WAS NO EXCEPTION.

THE ORGANIZATION RAPTOR RESOURCE PROJECT WAS FOUNDED IN 1988 BY BOB ANDERSON WHO SUCCESSFULLY MANAGED TO BREED FALCONS AND RETURN THEM TO THE WILD BY RELEASING THEM ON THE CLIFFS.

ARTIFICIAL NEST BOXES WERE ALSO PUT UP ALONG THE UPPER MISSISSIPPI BLUFFS AND TODAY THE PEREGRINE FALCONS ARE BACK IN NUMBERS WHERE THEY ARE NO LONGER CONSIDERED CRITICALLY ENDANGERED.

BUT THE CONTINUED WORK PROTECT AND MONITOR THEM AND THEIR HABITAT IS STILL CRUCIAL.

WHICH BRINGS US BACK TO WHERE THIS STORY STARTED TO THE STEEP CLIFFS OF THE DRIFTLESS BLUFFS.

(ROB) SO WE'RE ON A BIG SOYBEAN FIELD UP ON THE TOP OF THIS BLUFF, BUT OVER THERE IS A BIG CLIFF THAT OVERLOOKS THE MISSISSIPPI RIVER AND WE THINK THAT OVER THERE MAY BE THE NEST OF A PEREGRINE FALCON.

NOW WHETHER OR NOT THIS ONE ACTUALLY HAS CHICKS IN IT IS YET TO BE DISCOVERED.

WE HAVE ALL OF OUR CLIMBING GEAR AND YOU'LL FIND OUT.

(♪ ) (DAVE KESTER) CLIMBER TO TOPSIDE OVER.

FOUR LIVE BABIES.

(AMY) I COULDN'T BELIEVE IT WHEN SHE FLEW INTO THAT POTHOLE I WAS LIKE “OH MY GOD YOU KNOW SHE WENT IN”.

THAT'S MUSIC TO MY EARS.

(ROB) THERE ARE PEREGRINE FALCONS RIGHT IN THAT NEST.

HOW COOL IS THAT?

(JONAS) TODAY IS AN ABSOLUTE SUCCESS.

ON THE THREE BLUFFS WE VISITED, A TOTAL OF SEVEN HEALTHY FALCON EYASS WERE FOUND AND TAGGED.

(AMY) NEXT, MALE BAND.

K OVER 37.

(CLIMBER) WITH WITH THE COLOR MARK THE WAY IT IS AND THE BIG LETTERS YOU KNOW THAT K OVER 42 FOR EXAMPLE, THAT'S READ MORE READILY VISIBLE IN A TELESCOPE.

(JONAS) THE THING THAT GOT US EXTRA EXCITED, WAS THAT THE EYASIS WE FOUND WERE IN NATURAL NEST SITES ON THE ROCK.

SO THIS IS WHAT'S REALLY COOL THERE'S ACTUALLY A NEST BOX MOUNTED ON THE ROCK FACE JUST MAYBE 40 YARDS DOWN THAT WAY.

BUT THIS IS WHAT THEY CHOSEN IS NATURAL CREVASSE RIGHT ON THE ROCK.

(DAVE) THEY'VE NEVER USED THIS HOLE BEFORE AND IT'S A BEAUTIFUL EYRIES.

IT'S IT'S IT'S DRY.

IT'S OUT OF THE ELEMENTS.

IT'S PREDATOR FREE.

COONS CAN'T GET HERE IT'S JUST IT'S ONE OF THE BEST IRIES I'VE SEEN IN A LONG TIME.

(JOHN) YOU KNOW THIS IS A GREAT STORY TO LET PEOPLE KNOW.

I THINK IT'S REALLY NEEDED BECAUSE WE WE SEE THAT THEY'RE OFF THE ENDANGERED SPECIES LIST.

YOU KNOW PEOPLE ARE MONITORING THEM.

THEY APPEAR TO BE HEALTHY.

WE'VE GOT THEM IN URBAN AREAS WE'VE GOT THEM ON NATURAL CAVITIES AND THINGS LIKE THAT.

AND SO THIS REALLY WAS THE ULTIMATE GOAL WAS TO GET BACK TO FALCONS ON ON THE BLUFFS.

AND WE ARE SO, IT'S SUCH A GREAT FEELING TODAY TO HAVE OUR SECOND SITE THAT WE'RE OUT HERE TODAY THAT WE'VE ACTUALLY FOUND FOUR YOUNG FALCONS.

THEY'RE IN A REALLY NICE LITTLE POTHOLE.

IT'S IT'S REALLY WHAT WE WERE LOOKING FOR.

(JONAS) HE'S SO CALM.

(ROB) THAT WAS FRIGGIN AWESOME.

(JONAS) THIS IS A SUCCESS STORY THAT REALLY TOUCHED US.

BUT MAYBE MORE IMPORTANTLY IT IS REMINDEDER THAT WE SHOULDN'T TAKE WHAT WE HAVE FOR GRANTED.

THE FALCONS AS WELL AS OTHER BIRDS OF PREY WERE ALMOST GONE.

AND SEEING FALCONS UP CLOSE IN THEIR NATURAL HABITAT IS SOMETHING I WAS DREAMING OF AS A KID.

NOW ROB AND I HAVE BROUGHT OUR KIDS HERE TO THE DRIFTLESS.

WE WANT OUR GROWING FAMILIES TO SEE WHAT IT MEANS TO LOVE A LAND AS SPECIAL AS THIS.

I WANT MY KIDS TO GET TO EXPERIENCE THE THINGS I DREAMT UP WHEN I WAS GROWING UP.

IN SMALL PLACES LIKE THIS ECOSYSTEMS ARE VERY SENSITIVE TO CHANGE.

THE DRIFTLESS REGION MAY HAVE SURVIVED MANY CHALLENGES IN THE PAST BUT THAT IS NO PROMISE IT CAN DO IT EVERY TIME.

IT IS UP TO US TO MAKE SURE THESE STORIES LIVE ON FOR FUTURE GENERATIONS.

FOR OUR KIDS.

IT SHOULDN'T ONLY BE SOMETHING THEY JUST LEARNED ABOUT FROM A BOOK OR FROM WATCHING A MOVIE, BUT TO SET FEET ON THE LAND AND FLOAT THE WATERS.

SEE THE BIRDS MIGRATE.

TRAVEL BACK IN TIME AND WALK IN THE FOOTSTEPS OF EARLY EXPLORERS.

OR FIND SECRET WORLDS THAT NO ONE KNEW EXISTED.

AND TO CONTINUE TO PASS ON THE DREAMS TO THEIR CHILDREN.

BUT MAKING SURE THAT CAN HAPPEN IS UP TO US.

WE CAN MAKE A DIFFERENCE NOW AND IT STARTS WITH A KNOWLEDGE OF HOW SPECIAL THIS PLACE REALLY IS.

I SAID IN THE BEGINNING THAT I HAD A HARD TIME PUTTING MY FINGER ON WHY THE DRIFTLESS REGION FELT SPECIAL AND I STILL CAN'T GIVE AN EASY ANSWER.

IT IS BOTH VERY SIMPLE AND AT THE SAME TIME VERY COMPLEX.

ON THE ONE HAND ITS NATURAL BEAUTY SHOULD SIMPLY BE ENOUGH OF AN ANSWER.

BUT LEAVING IT AT THAT DOESN'T SEEM ENOUGH.

WHAT WE HAVE SEEN AND WHAT WE HAVE EXPERIENCED DURING OUR TIME IN THE DRIFTLESS CAN BE SUMMED UP AS A WILD RIDE OF FASCINATING DISCOVERIES.

NOW ROB AND I ARE ACTING AS THE GUIDES FOR OUR FAMILIES IN THIS AREA WE ONLY RECENTLY FOUND OUT EXISTED.

A RELATIVELY SMALL AREA PERHAPS BUT NEVERTHELESS FILLED WITH HIDDEN STORIES.

THE STORIES OF THE LAND THAT THE GLACIER SPARED.

(♪ ) (ROB) RIVER RAT FOREVER (TIM) IT WAS SO FREAKY, THAT CAVE, TRYING TO SQUEEZE THROUGH THAT LITTLE OPENING ♪ I DANCED AND RAN ♪ THROUGH THE TALL GRASS ♪ AND FLOWERS ♪ IN THE DAYLIGHT, ♪ I FELT HEAVEN'S RAIN SHOWERS ♪ I WAS YOUNGER ♪ I SAW THOSE LOVING ♪ SPIRITS PLAY ♪ I WAS YOUNGER ♪ LIVING AND BREATHING ♪ AND DREAMING BIG ♪ AT THE END OF THE DAY ♪ END OF THE DAY