NARRATOR: SOME NATURAL WONDERS ARE SIMPLY THE MOST EXTREME PLACES ON EARTH IN WHICH TO LIVE.

IN THE GREATEST MOUNTAIN RANGE ON EARTH, A HERDER MUST GUIDE HIS YAKS DOWN A TREACHEROUS GORGE TO GET THEM TO THEIR SUMMER PASTURES.

[SINGING IN NATIVE LANGUAGE] DEEP IN THE AMAZON RAINFOREST, AN INDIGENOUS VILLAGE MUST LEARN HOW TO SAVE THEIR BEAUTIFUL HOME FROM THE THREAT OF FIRE; WHILE IN THE ARCTIC, A GRANDMOTHER MUST SLIP BELOW THE SEA ICE TO COLLECT FOOD FOR HER FAMILY.

THIS IS THE STORY OF THESE WONDERS AND OF THE PEOPLE FIGHTING TO SURVIVE... MAN: GO!

AND EVEN TRIUMPH... [SPEAKING NATIVE LANGUAGE] IN THESE ASTONISHING PLACES.

EARTH'S NATURAL WONDERS ENCOMPASS A HUGE VARIETY OF LANDSCAPES-- LUSH, TROPICAL FORESTS...

SPECTACULAR ISLANDS...

SOARING MOUNTAIN RANGES... OR FROZEN POLAR WORLDS.

AND FOR THE PEOPLE WHO CALL THESE EXTRAORDINARY PLACES HOME, SURVIVAL REQUIRES SKILL...

INGENUITY... OK. AND BRAVERY.

OHH!

[SINGING] THIS PROGRAM WAS MADE POSSIBLE IN PART BY CONTRIBUTIONS TO YOUR PBS STATION FROM VIEWERS LIKE YOU.

THANK YOU.

NARRATOR: THE CANADIAN ARCTIC... AN EXTRAORDINARY NATURAL WONDER THAT MAKES UP ALMOST 40% OF CANADA'S ENTIRE LANDMASS.

THIS COASTAL LANDSCAPE IS FROZEN SOLID FOR OVER HALF THE YEAR.

[WIND WHISTLING] IN WINTER, TEMPERATURES AVERAGE MINUS 4 DEGREES FAHRENHEIT.

BUT, UNBELIEVABLY, PEOPLE LIVE HERE.

[WOMAN SPEAKING INUKTITUT] 63-YEAR-OLD MINNIE NAPPAALUK HAS LIVED IN THE REMOTE VILLAGE OF KANGIQSUJUAQ ALL HER LIFE.

SURVIVAL FOR THIS COMMUNITY OF 700 STILL MEANS GETTING MOST OF THEIR FOOD FROM THE LAND.

BUT IN WINTER, MINNIE HAS A VERY SPECIAL PLACE TO FIND CALORIES.

AND TOMORROW, SHE'LL BE SHOWING HER GRANDDAUGHTER EVA HOW TO CARRY ON A TRADITION THAT, WHILE INCREDIBLY DANGEROUS, IS AN IMPORTANT PART OF KANGIQSUJUAQ'S DIET THIS TIME OF YEAR.

[MINNIE SPEAKING INUKTITUT] 7 A.M. MINNIE AND HER SISTER SIASSIE ARE UP EARLY... AND HEADING OUT ONTO THE SEA ICE WITH EVA.

THIS IS SOMETHING THE WOMEN OF KANGIQSUJUAQ HAVE DONE FOR GENERATIONS.

[EVA SPEAKING INUKTITUT] THEY ARE NOW 10 MILES OUT FROM CONTINENTAL LAND UPON FROZEN SEA ICE.

IT MIGHT LOOK LIKE THERE'S NOTHING HERE, BUT MINNIE KNOWS OTHERWISE.

[MINNIE SPEAKING INUKTITUT] THIS SEARCH IS ONLY POSSIBLE WHEN TIDES ARE AT THEIR MOST EXTREME.

[ICE CRUNCHING] AND NOW, AROUND THE EQUINOX, BOTH HIGH AND LOW TIDES CAN BE UP TO 60% GREATER THAN NORMAL.

FOR MINNIE, IT IS THE EXTREME LOW TIDE THAT PROVIDES HER OPPORTUNITY.

[CRUNCHING] AS THE TIDE GOES OUT, THE FROZEN SEA ICE DROPS BY OVER 40 FEET, AND UNDERNEATH, THE SEA BED IS NOW FULLY EXPOSED.

IT'S HERE THAT MINNIE WILL FIND HER SECRET PANTRY, BUT IT'S A RACE AGAINST TIME.

[CHOPPING ICE] THE WOMEN HAVE JUST 45 MINUTES TO DIG A HOLE THROUGH 6 FEET OF SOLID ICE... [SPEAKING INUKTITUT] AND HEAD UNDER BEFORE THE TIDE TURNS AND REFLOODS THE SEA BED.

THEY'RE THROUGH.

BUT WITH TONS OF CONSTANTLY SHIFTING ICE DOWN THERE, THEY NEED TO MAKE SURE IT'S SAFE BEFORE THEY GO IN.

THEY NEED TO LOOK ELSEWHERE.

THIS ONE'S GOOD...

BUT THE TIDE WILL BE BACK IN LESS THAN HALF AN HOUR.

THEY NEED TO MOVE FAST.

[WATER DRIPPING] THERE ARE FEW PLACES ON EARTH WHERE YOU CAN WALK UNDER THE SEA LIKE THIS.

IT'S A PERILOUS PLACE TO BE.

BECAUSE THE ICE ABOVE THEM IS NO LONGER SUPPORTED BY SEA WATER...

IT IS EXTREMELY UNSTABLE.

THE RISK OF IT COLLAPSING AT ANY MOMENT IS HIGH.

BUT FOR MINNIE, IT'S WORTH IT, FOR SHE HAS FOUND THE PRIZE SHE IS SEEKING: MUSSELS... THOUSANDS OF THEM.

IT'S A SEAFOOD BONANZA, BUT MINNIE IS ON CONSTANT GUARD.

THEY'VE BEEN UNDER FOR 20 MINUTES.

AND WHEN THESE SEA CAVES START TO REFILL, IT HAPPENS QUICKLY.

TIME TO GO.

THESE ARE ACTUALLY THE MOST DANGEROUS MOMENTS FOR THE WOMEN.

AS THE TIDE BEGINS TO REFILL THESE CAVES WITH WATER, ITS MOVEMENT SHIFTS THE HUGE ICE BLOCKS SITTING ABOVE THEIR HEADS.

THE RISK IS THAT THE HOLE THEY HAVE ENTERED BY CLOSES AS THE ICE MOVES, LEAVING THEM TRAPPED UNDERNEATH.

THEY'VE MADE IT...

BARELY.

THIS WAS ONE OF AROUND 12 DAYS IN THE YEAR WHEN THEY CAN ACCESS THE CAVES.

FOR THESE MUSSEL GATHERERS, THIS RISKY EXPEDITION IS WORTH IT, AND EVA HAS LEARNED SOME IMPORTANT SKILLS THAT WILL LAST HER A LIFETIME.

GATHERING FOOD LIKE THIS IS A CENTURIES' OLD TRADITION THAT PROVIDES REMOTE COMMUNITIES LIKE MINNIE'S WITH IMPORTANT CALORIES AT A DIFFICULT TIME OF YEAR.

BUT THE CLIMATE IS CHANGING IN THIS NATURAL WONDER.

FOR NOW, AT LEAST, ANCIENT SKILLS STILL ALLOW NORTHERN CANADA'S INUIT PEOPLE TO SURVIVE IN A MODERN WORLD.

BUT FOR OTHERS, CHANGE IN THEIR ENVIRONMENT IS ALREADY HAVING A MAJOR IMPACT.

THE HIMALAYA-- POSSIBLY THE MOST ICONIC NATURAL WONDER OF THEM ALL.

IT'S THE GREATEST MOUNTAIN RANGE ON EARTH, HOME TO THE WORLD'S HIGHEST PEAK--MT.

EVEREST.

FORMED AROUND 50 MILLION YEARS AGO, THIS IS ONE OF THE YOUNGEST RANGES ON THE PLANET... AND IT'S STILL GROWING, BY AROUND 1/3 OF AN INCH EVERY YEAR.

THE DISTRICT OF MUSTANG SITS HIGH IN THE NEPALESE HIMALAYA.

THE THIN AIR AND EXTREME TERRAIN MAKE THIS A HARSH PLACE IN WHICH TO LIVE.

AND FOR THE HERDERS WHO CALL THESE MOUNTAINS HOME, YAKS ARE THE KEY TO SURVIVAL.

[MAN WHISTLING] [YAK GRUNTING] [SPEAKING NATIVE LANGUAGE] 49-YEAR-OLD THOKMAY LOWA LOOKS AFTER A HERD OF 200 YAKS.

HE IS HALFWAY THROUGH THE SPRING MIGRATION, MOVING THE HERD FROM WINTER TO SUMMER PASTURES.

TOMORROW, THEY FACE THE MOST DANGEROUS PART OF THE JOURNEY... GETTING THE HERD DOWN A TREACHEROUS 2,000-FOOT NEAR-VERTICAL PASS.

ALONG WITH HIS SISTER UTEN AND A SMALL GROUP OF HERDERS, THOKMAY SPENDS ALL WINTER HIGH IN THE MOUNTAINS IN SHELTERED GRAZING GROUNDS.

BUT NOW IT'S SPRING.

AND WITH MANY OF THE FEMALE YAKS PREGNANT AND FOOD SUPPLIES RUNNING LOW, THEY NEED TO REACH FRESH GRAZING AS QUICKLY AS POSSIBLE.

THAT MEANS A GRUELING 27-MILE TREK DOWN 5,000 FEET THROUGH SOME OF THE HIMALAYAS' MOST EXTREME MOUNTAIN TERRAIN.

WITH 4 DAYS LEFT, THE GOING ONLY GETS TOUGHER.

[MEN SPEAKING NATIVE LANGUAGE] EVERYONE IS EXHAUSTED, AND SUPPLIES ARE RUNNING DANGEROUSLY LOW.

AND NOW THERE'S ANOTHER PROBLEM.

THE UNPREDICTABLE WEATHER MEANT YAKS MATED LATER THAN USUAL THIS YEAR.

NOW THEY'RE CALVING HALFWAY THROUGH THE MIGRATION.

THOKMAY CAN HARDLY REMEMBER THIS EVER HAPPENING BEFORE.

THE CALVES, SOME JUST A DAY OLD HAVE TO RUN THE GAUNTLET OF THIS TAXING MIGRATION.

AND THE DESCENT THROUGH THIS TREACHEROUS PASS IS THE MOST DANGEROUS SECTION OF THE ENTIRE TRIP.

THERE IS NO VIABLE ALTERNATIVE.

TO AVOID THE PASS WOULD MEAN A LENGTHY DETOUR THAT COULD KILL HALF THE HERD.

IN THE MORNING, THOKMAY WILL PUT EVERYTHING HE'S GOT ON THE LINE.

DAWN.

THE HERDERS ARE UP, PREPARING FOR THEIR BIG DESCENT.

BEFORE THEY SET OFF, THEY ENGAGE IN A TIMELESS RITUAL... [SPEAKING NATIVE LANGUAGE] THE PUJA.

THOKMAY CAREFULLY UNROLLS A PRAYER FLAG... AND STRETCHES IT OUT ACROSS THE MOUTH OF THE GORGE THEY'RE ABOUT TO ENTER.

[THOKMAY SHOUTING; ECHOING] BY MARKING THE GORGE WITH THESE FLAGS AND OFFERING UP PRAYERS, HE HOPES TO BE BLESSED WITH STRENGTH AND ULTIMATELY A SAFE PASSAGE.

PRAYER'S OVER.

TIME FOR A LEAP OF FAITH.

THE FIRST YAKS BEGIN TO HEAD DOWN THE TOP OF THE PASS.

[MAN GRUNTING] IT'S NARROW AND VERY STEEP... AND THE GROUND IS INCREDIBLY UNSTABLE.

SOME OF THE YAKS HAVE MADE THIS DESCENT BEFORE, BUT THEY'RE STILL RELUCTANT.

WITH A LITTLE PERSUASION, UTEN GETS THEM MOVING DOWN.

[UTEN SHOUTS] AND NOW A BANK OF DENSE FOG IS CLOSING IN.

FINALLY, AFTER 2 HOURS, ALL THE YAKS ARE THROUGH THE MOST DANGEROUS PART OF THE GORGE.

BUT THE DESCENT HAS TAKEN ITS TOLL ON SOME OF THE HERD.

ONE OF THE CALVES IS BADLY INJURED.

BUT YAKS ARE SO VALUABLE, LEAVING IT BEHIND IS UNTHINKABLE.

IT WILL BE CARRIED FOR THE REMAINDER OF THE JOURNEY.

AND THEY STILL HAVE TO NEGOTIATE THEIR WAY ACROSS SEVERAL MILES OF ROUGH TERRAIN.

[BELL CLANGING] IT TAKES A FURTHER 3 DAYS OF HARD TREKKING.

FINALLY, HOME IS IN SIGHT.

[WHISTLES] THIS YEAR'S LONG MIGRATION IS OVER.

FOR UTEN, IT'S AN EMOTIONAL REUNION AFTER 6 MONTHS AWAY FROM HER YOUNG SON.

WHILE THE HERD ENJOY THE SUMMER GRAZING... THOKMAY ENJOYS SOME OF THE COMFORTS OF HOME WITH HIS WIFE AND DAUGHTER.

IT MIGHT BE SLOW, BUT CHANGE IS COMING TO THESE MOUNTAINS.

THOKMAY WILL HAVE TO DEAL WITH NEW CHALLENGES ON THESE GRUELING MIGRATIONS IF HE AND HIS FAMILY ARE TO CONTINUE LIVING HERE.

BUT IN OTHER NATURAL WONDERS, THE ENVIRONMENT HAS ALREADY CHANGED, AND IT IS NOW THREATENING NOT JUST PEOPLE AND THEIR WAY OF LIFE, BUT THE VERY WONDER ITSELF.

THE AMAZON BASIN-- HOME TO THE LARGEST RAINFOREST ON EARTH.

[BIRDS CALLING] OVER 380 BILLION TREES...

COVERING AROUND 1/3 OF SOUTH AMERICA'S ENTIRE LANDMASS.

A UNIQUE NATURAL WONDER, HOME TO A DIZZYING ARRAY OF PLANTS, ANIMALS, AND INSECTS, WHERE NEW SPECIES ARE STILL BEING DISCOVERED.

BUT NOW SWATHES OF THIS RAINFOREST ARE BEING DESTROYED... BY FIRE.

IT IS THE HEIGHT OF FIRE SEASON, AND HUNDREDS OF THEM ARE BURNING ACROSS THE AMAZON.

[SPEAKING PORTUGUESE] EDIMAR DOS SANTOS ABREU IS CHIEF OF THE ALIANCA FIRE BRIGADE.

HE AND HIS TEAM OF 8 FIREFIGHTERS ARE RESPONSIBLE FOR PROTECTING A PART OF THE MATA GROSSO REGION, LYING IN THE WEST OF BRAZIL.

IT'S A HUGE AREA, THE SIZE OF FLORIDA.

MOST OF THE FIRES THEY DEAL WITH ARE SET BY FARMERS CLEARING LAND THAT BECAUSE OF CHANGING CLIMATIC CONDITIONS OFTEN RAGE OUT OF CONTROL.

THE FIRES ARE NOW ENDANGERING THE XINGU NATIONAL PARK.

MUCH OF THIS REGION IS MADE UP OF VIRGIN RAINFOREST.

[PROPELLER WHIRRING] TODAY, EDIMAR AND HIS TEAM ARE FLYING INTO THE XINGU.

THEY'RE WORKING WITH A GROUP WHOSE VERY EXISTENCE IS NOW THREATENED BY THE FIRES.

[BELLS JINGLING] [CHANTING] THE KAMAIURA ARE ONE OF 14 INDIGENOUS GROUPS WHO LIVE HERE.

THEY RELY ON THE FOREST FOR EVERYTHING... FROM THE MATERIAL THEY USE TO BUILD THEIR HOUSES TO THE FOOD THEY EAT.

NOW THE FIRES ARE PUTTING THEIR LIVELIHOOD AT RISK... AND THEY DON'T HAVE THE TOOLS TO CONTROL THEM.

AS EDIMAR FLIES OVER THE AREA, THE SHEER SCALE OF THE PROBLEM IS ALL TOO CLEAR.

DEFORESTATION HAS BECOME SO WIDESPREAD, IT'S UPSET THE DELICATE MICROCLIMATE.

WITHOUT THE DENSE CANOPY OF TREES, HUMIDITY ACROSS THE REGION HAS DROPPED DRAMATICALLY, AND THE GROUND IS NOW TINDER BOX DRY.

LIKE MANY INDIGENOUS PEOPLES AROUND THE WORLD, THE KAMAIURA HAVE FOR CENTURIES USED FIRE TO CLEAR LAND FOR THEIR CROPS, BUT THIS ENVIRONMENT IS CHANGING FAST.

THE EVER-DRIER GROUND MEANS FIRES THAT FORMERLY STAYED CONTAINED CAN NOW QUICKLY SPIRAL OUT OF CONTROL.

[ALL SPEAKING NATIVE LANGUAGE] EDIMAR AND HIS TEAM ARE TRAINING THE KAMAIURA TO BE FIREFIGHTERS, AND IT'S NOT LONG BEFORE THEY ARE ALL CALLED INTO ACTION.

A FIRE IS SWEEPING THROUGH THE FOREST JUST A FEW MILES AWAY.

[MOTORCYCLE ENGINES] IF THE WIND CHANGES DIRECTION, IT COULD THREATEN THE VILLAGE.

WITH THE GROUND THIS DRY, THE FIRE WILL SPREAD RAPIDLY.

[FLAMES CRACKLING] THEY CREATE A FIREBREAK, CLEARING A LINE OF LAND OF ANY COMBUSTIBLE MATERIAL.

THIS BARRIER IS A SIMPLE BUT EFFECTIVE WAY OF STOPPING A FIRE IN ITS TRACKS.

IT TAKES SEVERAL HOURS...

BUT THEY EVENTUALLY MANAGE TO GET THE BLAZE UNDER CONTROL.

IN THE PAST, THE KAMAIURA DIDN'T NEED THESE FIREFIGHTING SKILLS.

THE MORE HUMID ENVIRONMENT MEANT FIRES DIDN'T SPREAD.

BUT NOW MATA GROSSO'S FIRES ARE GROWING STEADILY WORSE WITH EACH PASSING YEAR.

AND AS EDIMAR LEAVES THE KAMAIURA, A CALL COMES IN THAT ANOTHER FIRE HAS TAKEN HOLD 200 MILES AWAY, AND IT'S ENORMOUS.

10 SQUARE MILES OF VIRGIN RAINFOREST IS ABLAZE.

[SPEAKING NATIVE LANGUAGE] BY THE TIME EDIMAR AND HIS TEAM REACH THE SITE, IT'S BEEN BURNING FOR 12 HOURS.

THE SHEER SCALE OF THE TASK FACING THIS SMALL TEAM IS DAUNTING.

BY DAYBREAK, ONE SECTION OF THE FIRE IS FINALLY UNDER CONTROL.

THE TEAM HAVE MANAGED TO STOP IT SPREADING ANY FURTHER.

THEY HAVE NOW BEEN WORKING FOR 14 HOURS STRAIGHT.

BUT DURING THE HEIGHT OF FIRE SEASON, THIS IS A NORMAL SHIFT.

[EDIMAR SPEAKING PORTUGUESE] THE RATE OF CHANGE IN THE FORESTS OF THE AMAZON IS SOBERING.

AND TRADITIONAL COMMUNITIES WILL HAVE TO LEARN NEW SKILLS IF THEY'RE TO CONTINUE TO LIVE HERE.

IN ONE NATURAL WONDER, PEOPLE HAVE DONE JUST THAT BY USING TECHNOLOGY AND LEARNING NEW SKILLS TO SURVIVE AND EVEN THRIVE IN AN AREA THAT ONCE SUPPORTED LITTLE LIFE.

AUSTRALIA... AND IN QUEENSLAND, A NATURAL WONDER 4 TIMES THE SIZE OF ARIZONA...

THE OUTBACK-- A HUGE, UNBROKEN EXPANSE OF WILDERNESS, ONE OF THE PLANET'S GREAT SEMI-ARID LANDSCAPES.

SCORCHED BY TEMPERATURES OF MORE THAN 100 DEGREES FAHRENHEIT... ONLY THE HARDIEST SPECIES CAN SURVIVE IN THIS SEARING HEAT.

[CATTLE LOWING] BUT IN RECENT YEARS, THANKS TO TECHNOLOGY, A NEW USE HAS BEEN FOUND FOR THIS EXTREME LANDSCAPE-- SUPER-SIZED CATTLE FARMS.

AROUND 10 MILLION BEEF CATTLE ROAM THE OUTBACK HERE.

BUT TO SURVIVE IN THIS HOSTILE TERRAIN, THE COWS NEED A HUGE AREA TO GRAZE ACROSS.

VEGETATION IS SPARSE, AND THEY MUST COVER ENORMOUS DISTANCES IN SEARCH OF FOOD AND WATER.

AS A RESULT, THE CATTLE FARMS ARE VAST.

ROUNDING UP ALL THE ANIMALS FOR MARKET IS A MASSIVE TASK, AND IT TAKES A VERY SPECIAL KIND OF COWBOY... [HELICOPTER BLADES WHIRRING] ONE THAT CAN FLY A HELICOPTER.

IT'S DANGEROUS WORK.

[MAN TALKING OVER RADIO] MAN: A LOT OF THE UNFORTUNATE ACCIDENTS THAT HAPPEN WHERE THE PILOTS DON'T GET HOME TO THEIR FAMILIES.

AND, YEAH, WE DO SEE A LOT OF THEM EVERY SEASON.

NARRATOR: 24-YEAR-OLD CHRIS WEYAND IS AN OUTBACK RANCHER BORN AND BRED.

[WHISTLES] GO, SHELLY.

[CATTLE LOWING] NARRATOR: HE HAS WORKED AS A COWBOY SINCE THE AGE OF 15.

CHRIS: I'VE ALWAYS LOVED THE BUSH AND JUST THE WAY OF LIFE THAT'S OUT HERE.

STILL, THE LAST FRONTIER IN SOME AREAS THAT ISN'T SO DEVELOPED.

AND THE JOB'S NOT YOUR 9-5.

IT'S YOUR LIFE.

NARRATOR: BUT LAST YEAR, CHRIS SWITCHED FROM HORSES TO HELICOPTERS.

AND TODAY, HE'S FACING HIS BIGGEST TEST YET: ROUNDING UP OVER 300 HEAD OF CATTLE AND DRIVING THEM ACROSS THE BUSH TO THEIR HOLDING PENS READY FOR MARKET.

HE'S BEING MENTORED BY SENIOR HELI MUSTERER LES PAYNE.

BASICALLY, WHEN WE GET OUT THERE, IF YOU JUST FOLLOW ME AROUND FOR A WHILE, AND I'LL SHOW YOU FROM THE AIR THE AREAS WE'RE GONNA WORK.

YEAH, NO WORRIES.

SOUNDS GOOD.

NARRATOR: BUT IN THE HELI MUSTERING BUSINESS, THERE'S NO ROOM FOR ERROR.

LES: GOOD TO GO?

CHRIS: YEAH, GOING ALL RIGHT.

NARRATOR: THE PRESSURE IS ON.

CHRIS, VOICE-OVER: I THINK IT'S DANGEROUS IN A LOT OF WAYS.

YOU KNOW, IF SOMEONE MAKES A MISTAKE, IT COMES UP PRETTY QUICKLY, AND THERE'S NOT MUCH MARGIN FOR ERROR.

LES: YOU SEE WHERE WE GOTTA GO UP THERE?

CHRIS: YEAH, I THINK I SEE THE DUST UP ON THE ... NARRATOR: THE FIRST CHALLENGE IS FINDING THE CATTLE.

LES: ALERT YOU UP ON THIS RANGE HERE.

HOW YOU GONNA HANDLE 'EM?

CHRIS: GOOD TO GO.

NARRATOR: CHRIS NEEDS TO DRIVE THE CATTLE OUT FROM UNDER THE TREES AND INTO THE OPEN, SO HE PERFORMS A MANEUVER MOST PILOTS WOULD NEVER NORMALLY ATTEMPT: DROPPING FROM 2,000 FEET TO AROUND 30 FEET IN A MATTER OF SECONDS.

HE'S AIMING TO SPOOK THE CATTLE AND FLUSH THEM OUT FROM AMONG THE TREES.

LES: ANY TROUBLE OVER THERE, MATE?

CHRIS: YEAH, GOIN' ALL RIGHT.

NARRATOR: BY FLYING THIS LOW AND SLOW, HELI MUSTERERS PUT THEMSELVES IN WHAT THEY CALL THE DEAD MAN'S CURVE.

IT'S A RISKY PLACE TO BE.

CHRIS, VOICE-OVER: BEING IN THAT HEIGHT, YOU'VE GOT A LOT LESS TIME TO REACT TO OBSTACLES.

IF SOMETHING GOES WRONG, YOU COULD BE ON THE GROUND IN JUST A MATTER OF SECONDS.

NARRATOR: WITHIN A COUPLE OF HOURS, HE'S FORCED THE BIG HERD INTO THE OPEN BUSH.

THE DAY IS WEARING ON.

THERE'S STILL 5 MILES TO COVER IF THEY'RE TO REACH THE HOLDING PEN BEFORE NIGHTFALL.

THEY'RE NOW JOINED BY A GROUND SUPPORT TEAM.

BUT AS A KEY PART OF THE MUSTER, CHRIS AND LES MUST MAKE SURE THAT THE HERD ARE HELD TOGETHER AND GUIDED HOME.

CHRIS, VOICE-OVER: YOU GOTTA BE A GOOD STOCK MAN AND UNDERSTAND WHAT'S HAPPENING-- THE CATTLE, THE LANDSCAPE.

YOU GOTTA BE ABLE TO READ THAT.

NARRATOR: ON THE OPEN GROUND, THEY'RE MAKING GOOD PROGRESS.

BUT STANDING BETWEEN THEM AND THE HOLDING PEN IS A FINAL OBSTACLE, ONE FEARED BY EVERY HELI MUSTERER: WATER.

LES: YOU SEE WHERE WE GOTTA GO UP THERE?

CHRIS: YEAH, I THINK I SEE THE WATER.

NARRATOR: IT'S POTENTIALLY A CATASTROPHIC HAZARD.

AT THIS HEIGHT, SPRAY IS WHIPPED UP BY THE ROTARY BLADES AND CAN EASILY BE SUCKED INTO THE FUEL INTAKE.

THAT WOULD BRING CHRIS' HELICOPTER DOWN INSTANTLY.

CHRIS, VOICE-OVER: WHEN YOU'RE ABOVE WATER, AND THE FACT THAT THE WATER'S MOVING, IT CAN DISORIENTATE PILOTS.

AND UNFORTUNATELY, SOME PEOPLE CAN END UP DIVING INTO THE WATER OR STRIKING A BIT OF THE WATER.

LES: YOU GOOD, EH?

CHRIS: YEAH.

NO WORRIES HERE.

NARRATOR: CHRIS NEEDS TO STAY THIS LOW TO KEEP THE HERD MOVING... AND IT'S WORKING.

LES: A BIT SLOW TO GET THEM GOING WITH ALL THAT WATER SPREAD.

YOU KNOW, THEY'RE ALL OVER THE SHOW.

NARRATOR: FINALLY, THEY GET ALL THE HERD SAFELY ACROSS THE RIVER.

AFTER HOURS OF FLYING IN GRUELING 104-DEGREE HEAT... CHRIS AND LES MAKE IT TO THE HOLDING PEN.

[CATTLE LOWING] WHETHER OR NOT YOU HAVE MODERN TECHNOLOGY AT YOUR FINGERTIPS, SURVIVING IN SOME OF EARTH'S NATURAL WONDERS MEANS ADAPTING TO RAPIDLY CHANGING ENVIRONMENTS AND MAKING THE MOST OF THEM, AND THAT INCLUDES SPOTTING A NEW OPPORTUNITY IN ONE OF THE MOST UNLIKELY PLACES...

THE SIBERIAN TUNDRA, A NATURAL WONDER SHAPED BY THE WINDS AND GLACIERS OF THE LAST ICE AGE.

THIS LANDSCAPE STRETCHES AROUND A MILLION SQUARE MILES ACROSS NORTHERN RUSSIA.

YAKUTIA, IN THE EASTERN CORNER OF THIS REGION, IS ONE OF ITS MOST REMOTE PARTS.

IN WINTER, IT'S A FROZEN WILDERNESS BLASTED BY ARCTIC WINDS, WHERE ALMOST NOTHING SURVIVES.

BUT IN SUMMER, THIS LANDSCAPE IS COMPLETELY TRANSFORMED.

FROZEN TUNDRA BECOMES A VAST, COLORFUL ECOSYSTEM AWASH WITH FLORA AND FAUNA.

AND THE LANDSCAPE IS PEPPERED WITH A MAGNIFICENT TAPESTRY OF LAKES AND POOLS.

ANTON MALARDAROV LIVES IN MOSCOW, BUT HE WAS BORN AND RAISED IN THIS WILDERNESS.

[ANTON SPEAKING NATIVE LANGUAGE] EVERY SUMMER, HE RETURNS AND REUNITES WITH OLD FRIENDS TO SEARCH FOR BURIED TREASURE...

ANCIENT MAMMOTH TUSKS.

BUT FINDING THEM IS LIKE LOOKING FOR A NEEDLE IN A HAYSTACK.

ANTON AND THE TEAM HAVE BEEN HERE FOR A WEEK, LIVING ALMOST ENTIRELY OFF THE LAND.

THEY'VE BEEN SCOURING VAST AREAS OF THIS TUNDRA, LOOKING FOR MAMMOTH TUSKS.

BUT THE SEASON IS NOW COMING TO AN END, AS THE SIBERIAN WINTER APPROACHES.

THE KEY TO THEIR SEARCH IS A LAYER OF FROZEN SUBSOIL KNOWN AS PERMAFROST.

STRETCHING TO A DEPTH OF 4,500 FEET, IT HAS EXISTED FOR MILLENNIA.

BUT IN RECENT TIMES, RISING TEMPERATURES HAVE MEANT THAT EVER MORE OF IT IS THAWING IN THE SUMMER MONTHS.

AND THE REMAINS OF MAMMOTHS BURIED DEEP IN THE PERMAFROST FOR THOUSANDS OF YEARS ARE NOW BEING EXPOSED, INCLUDING THEIR TUSKS.

WITH THE SALE OF IVORY BANNED ACROSS MUCH OF THE WORLD, MAMMOTH TUSK HUNTING IS CONTROVERSIAL.

WHILE SOME SEE THIS AS AN ALTERNATIVE THAT COULD LIMIT ELEPHANT POACHING, OTHERS BELIEVE IT ONLY ENCOURAGES THE GLOBAL TRADE IN IVORY.

BUT FOR NOW, ANTON'S SEARCH IS A LEGAL ACTIVITY IN ACCORDANCE WITH THE CONVENTION ON INTERNATIONAL TRADE AND ENDANGERED SPECIES... AND THERE ARE A LOT OF ANCIENT TUSKS OUT THERE SOMEWHERE.

EARLY MORNING.

AFTER A QUICK BREAKFAST, THE MAMMOTH HUNTERS BEGIN THEIR SEARCH.

THEY START BY LOOKING ALONG THE BANKS OF THE RIVER BENEATH THE PERMAFROST LAYERS.

ANTON HOPES THAT THE THAWING PERMAFROST MAY HAVE EXPOSED TUSKS OR CAUSED THEM TO COLLAPSE ONTO THE BANK.

BEFORE LONG, ONE OF THE TEAM SPOTS SOMETHING ON THE RIVERBANK.

THE TEAM CAREFULLY EXCAVATE THE AREA.

IT'S A MAMMOTH TUSK AND A DECENT-SIZED ONE, BUT IT'S NOT IN GOOD CONDITION.

MAMMOTH TUSKS COME IN 3 GRADES DETERMINED BY HOW WELL-PRESERVED THE IVORY IS.

THIS IS GRADE 3, THE LOWEST QUALITY.

IT'S STILL WORTH AROUND $2,000.

BUT TO MAKE THIS TRIP WORTHWHILE, ANTON NEEDS TO COLLECT AT LEAST 30 TIMES THIS AMOUNT.

AND AS MAMMOTH REMAINS ARE OFTEN FOUND IN GROUPS, HE'S CONFIDENT HE'LL FIND MORE HERE.

JUST DOWNSTREAM, THEY SPOT SOMETHING POKING OUT OF THE WATER.

THIS TIME, IT LOOKS LIKE IT IS FRESHLY EMERGED FROM THE PERMAFROST.

THE QUALITY APPEARS EXCELLENT.

IT'S NOT AS BIG AS THE TUSK THEY FOUND PREVIOUSLY, BUT IF IT'S CONFIRMED TO BE GRADE 1, IT'LL BE WORTH AROUND $5,000.

AND THAT WOULD BE A BIG STEP TOWARDS COVERING THE COST OF THIS TRIP.

MUCH OF THIS IVORY IS CARVED INTO ORNAMENTS AND JEWELRY AND SOLD LEGALLY TO CUSTOMERS IN CHINA.

BUT PRESSURE IS MOUNTING TO BAN THE SALE OF ALL IVORY THROUGHOUT THE WORLD IN ORDER TO REDUCE DEMAND.

TRIPS LIKE ANTON'S COULD SOON BECOME A THING OF THE PAST.

LIFE IN MANY OF EARTH'S NATURAL WONDERS IS CHANGING FASTER THAN EVER BEFORE.

AND IN ORDER TO SURVIVE, PEOPLE ARE HAVING TO ADAPT.

FOR SOME, IT MEANS DEVELOPING NEW SKILLS TO DEAL WITH VERY NEW PROBLEMS, WHILE IRONICALLY FOR OTHERS, IT MEANS PASSING ON ANCIENT SKILLS TO PUT FOOD ON THE TABLE.

BUT AS THESE NATURAL WONDERS CONTINUE TO CHANGE, THERE'S LITTLE DOUBT THAT PEOPLE WILL NEED AS MUCH INGENUITY, SKILL, AND COURAGE AS EVER IF THEY ARE TO GO ON LIVING IN THESE EXTRAORDINARY PLACES THEY CALL HOME.

THE TEAM THAT HEADED OUT TO THE CANADIAN ARCTIC TO CAPTURE THE LIVES OF THE INUIT MUSSEL HUNTERS KNEW THAT THEY WOULD FACE A LOT OF CHALLENGES.

THE TRIP WAS PLANNED TO COINCIDE WITH THE SPRING TIDES THAT ARE THE KEY TO THE HUNT.

THEY WOULD BE AT THEIR MOST EXTREME IN A FEW DAYS' TIME.

BUT FIRST, THE TEAM HAD TO MAKE SURE THAT THEY AND THEIR KIT COULD ADAPT TO THE ARCTIC CONDITIONS.

EVEN MOVING AROUND HERE WAS A CHALLENGE.

I'M STILL IN ONE PIECE, WILL.

OH!

HA HA HA!

[LAUGHTER] I JUST FELL OFF.

NARRATOR: WITH THE WEATHER THIS UNPREDICTABLE, PROGRESS WAS PAINFULLY SLOW.

MAN: VISIBILITY IS PRETTY...

PRETTY POOR TODAY.

I WANT TO TRY AND GET A REVEAL SHOT OF THE TOWN.

[DRONE BUZZING] NARRATOR: THE TEAM WERE HERE FOR JUST A FEW DAYS.

IF CONDITIONS HAD REMAINED THIS BAD, THEY'D HAVE HAD NO CHANCE OF GETTING OUT ON THE SEA ICE TO FILM THE SEQUENCE THEY'D COME TO CAPTURE.

PETER: CAN'T REALLY SEE ANY DEFINITION AT THE MOMENT.

I JUST SEE THE WHITE FRAME.

NARRATOR: THEY WERE HOPING FOR BETTER WEATHER THE NEXT DAY.

MUSSEL HARVEST DAY.

PETER: OH, WE CAN GO, THOUGH.

IT'S FINE.

YOU GUYS CAN GO.

NARRATOR: AND THE WEATHER WAS PERFECT.

THE CREW FOLLOWED THE WOMEN OUT INTO THE BAY AHEAD OF LOW TIDE.

IT WOULD BE AT ITS LOWEST IN JUST 2 HOURS' TIME, BUT THE TEAM HAD FIRST TO FIND A SAFE SPOT TO FILM UNDER THE ICE.

[CHOPPING ICE] WHILST THE WOMEN DUG THEIR HOLE, THE CREW NEEDED A PARALLEL ONE SO THEY COULD CAPTURE ALL THE ACTION FROM BELOW.

I HOPE IT'S STRONG.

NARRATOR: DESPITE THE FIXER'S REASSURING WORDS, IT WAS VERY UNSTABLE UNDER THE ICE PACK, AND ONLY TWO OF THE CREW COULD GO UNDER.

DIRECTOR RUSSELL LEVEN AND CAMERAMAN WILL EDWARDS WOULD BE ON THEIR OWN.

THE TIDE WAS NOW FULLY OUT, AND THE CLOCK TICKING.

[WATER DRIPPING] RUSSELL: WE'VE JUST HEADED UNDER.

GOT ABOUT HALF AN HOUR, 45 MINUTES, MAYBE, TO SHOOT THE SEQUENCE THAT WE NEED.

IT'S VERY CRAMPED IN HERE.

EVERYBODY'S KIND OF STEPPING DOWN.

IT'S NOT UNLIKE POTHOLE, EH?

NARRATOR: THEY HAD A VERY SHORT WINDOW TO GET ALL THE ACTION BEFORE THE TIDE RETURNED.

BUT AS SOON AS THEY WERE IN, WILL IDENTIFIED A PROBLEM.

WILL: JUST GOT IN, AND WHAT WE'RE TRYING TO DO IS TRYING TO ACCLIMATIZE THE CAMERA.

SO WE'VE BEEN WRAPPING THE CAMERAS IN HEAT WARMERS SO THEY DON'T STEAM UP, 'CAUSE OUTSIDE'S MINUS 20, IN HERE'S 4.

SO WE GOT BIG CONDENSATION PROBLEMS.

SO WE'RE TRYING TO FIND A POSITION WHERE WE'RE NOT DRIPPING.

SO WE GOT A NICE DRY BIT HERE.

23 MINUTES.

NARRATOR: THEY NEEDED TO START FILMING.

MINNIE'S COMING IN NOW.

OH... NARRATOR: AS THE WOMEN STARTED COLLECTING MUSSELS, THE CRAMPED AND SLIPPERY CONDITIONS MADE IT HARD FOR EVERYONE.

WOMAN: AAH!

WILL: WHOA.

YOU ALL RIGHT?

YOU OK?

WOMAN: YES.

HOW MUCH TIME DO YOU THINK WE HAVE?

THEY'RE WORRIED ABOUT THE TIME.

NARRATOR: THE WOMEN HEADED DEEPER INTO THE CAVES, AND WILL HAD TO FOLLOW THEM.

WOMAN: AAH!

WILL: YOU'RE AT THE EDGE OF MY DISTANCE-- RUSSELL: SWITCH LENSES, WILL!

NARRATOR: RUSSELL HAD TO SHOUT HIS DIRECTIONS TO HIM, WHICH CREATED ITS OWN PROBLEMS.

RUSSELL: SIGNAL TO GET IT ROLLING.

MINNIE WAS JUST TELLING ME OFF THERE FOR SHOUTING.

'CAUSE WHEN YOU SHOUT, IT REVERBERATES AGAINST THE ICE.

WELL, IT MAKES THE ICE PACK UNSTABLE, WHICH IS OBVIOUSLY BAD NEWS, SO LESS LOUD.

[WATER DRIPPING] NARRATOR: WITH THE WATER COMING IN FAST, IT WAS TIME TO LEAVE.

RUSSELL: COME ON, WILL, LET'S GO.

OK, GUYS, FOR SAFETY, WE'RE GONNA COME OUT HERE.

CAN YOU HELP ME OUT?

WHOO!

NARRATOR: WILL WAS THE LAST ONE OUT.

THAT WAS ABSOLUTELY MENTAL.

UH...IT'S FLAT-OUT CRAWLING IN WATER.

WITH THE ICE AGAINST YOUR HEAD.

EVA TOOK ME DOWN SOME MAD, NARROW CHAMBERS.

SHE IS ONE BRAVE WOMAN.

ABSOLUTELY AMAZING.

AH!

RUSSELL: EVERYBODY'S SOAKING WET, SO THE PLAN NOW IS TO LEG IT HOME AND GET SOMETHING-- GET SOME DRY CLOTHES AND SOME HOT TEA INSIDE US.

[SNIFFS] BUT A GREAT SESSION.

NARRATOR: IT WAS TOUGH WORK, BUT THE "EARTH'S NATURAL WONDERS" TEAM MANAGED TO CAPTURE A UNIQUE FOOD HARVESTING TRADITION PRACTICED IN FEW OTHER PLACES ON THE PLANET.

STAY TUNED FOR MORE "EARTH'S NATURAL WONDERS" NARRATOR: NEXT TIME...

IN "EARTH'S NATURAL WONDERS" HOW ANIMALS CAN MAKE THE DIFFERENCE BETWEEN LIFE... AND DEATH AS PEOPLE STRUGGLE TO SURVIVE IN SOME OF THE PLANET'S MOST EXTRAORDINARY PLACES.

OHH!

THIS PROGRAM WAS MADE POSSIBLE IN PART BY CONTRIBUTIONS TO YOUR PBS STATION FROM VIEWERS LIKE YOU.

THANK YOU.

"EARTH'S NATURAL WONDERS" LIFE AT THE EXTREMES IS AVAILABLE ON DVD AND BLU-RAY.

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