"[ DINOSAURS ROARING ]" "Narrator:" "OUR WORLD WAS ONCE DOMINATED BY DINOSAURS." "THEY WALKED WHERE WE WALK." "THEY DRANK THE SAME WATER BREATHED THE SAME AIR AND FOUGHT ON THE SAME BATTLEFIELDS." "BUT THEN THEY FACED A DAY" "THAT NONE OF US CAN IMAGINE SOME OF THE MOST CRITICAL HOURS" "IN THE HISTORY OF LIFE ON EARTH." "THIS IS THE STORY OF THE DAY THEIR WORLD ENDED " "THE LAST DAY OF THE DINOSAURS." "CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS" "EARTH, 65 MILLION YEARS AGO." "[ THUNDER CRASHING ]" "ALONG THE WEST COAST OF WHAT'S NOW NORTH AMERICA," "MOUNTAINS TOWER OVER A LUSH, FORESTED VALLEY." "IT'S THE DOMAIN OF THE ULTIMATE FORMS OF PREHISTORIC EVOLUTION." "AT MORE THAN 350 POUNDS, WITH A WINGSPAN OF 40 FEET," "QUETZALCOATLUS IS THE LARGEST FLYING CREATURE OF ALL TIME." "A MILE DOWN, A BREAKFAST NO CARNIVORE CAN RESIST." "[ EGGSHELL CRACKING ]" "IT WILL TAKE THIS TINY HATCHLING 18 YEARS" "TO BECOME THE AGE'S MOST FEARSOME PREDATOR." "FOR NOW, TYRANNOSAURUS REX" "IS JUST A FEW INCHES TALL AND COMPLETELY EXPOSED..." "[ GROWLING ] ...BUT NOT COMPLETELY UNPROTECTED." "THE FATHER, A FULLY GROWN T. REX, IS ON THE HUNT." "HIS ACUTE SENSE OF SMELL" "HELPS HIM SNIFF OUT PREY FROM GREAT DISTANCES." "AND IT ALSO SERVES HIM WELL AS A PARENT." "HE KNOWS WHEN SOMETHING IS WRONG." "[ ROARS ]" "[ SCREECHES ]" "[ GRUNTS ]" "QUETZALCOATLUS' METABOLISM" "DEMANDS THAT IT EAT REGULARLY." "AND POWERING THIS STREAMLINED BODY" "MEANS FINDING RICH SOURCES OF PROTEIN," "LIKE A THREE-POUND BABY T. REX." "[ SCREECHES ]" "[ SCREECHES ]" "[ ROARS ]" "QUETZALCOATLUS IS LUCKY..." "THIS TIME." "OF THE ENTIRE CLUTCH OF T. REX EGGS," "ONLY ONE CHICK SURVIVES." "AND IF IT GROWS UP," "IT WILL GROW TO BE 17 FEET TALL" "AND WEIGH MORE THAN SEVEN TONS." "BUT SURVIVING TO ADULTHOOD," "EVEN FOR TYRANNOSAURUS REX," "ISN'T WRITTEN IN STONE." "THIS IS THE ASTEROID BELT BETWEEN MARS AND JUPIT " "BILLIONS OF ROCKS ALL HURTLING THROUGH SPACE" "IN THE SAME DIRECTION," "LIKE TRAFFIC ON A FREEWAY ALL EXCEPT THIS ONE." "IT'S GOING 22,000 MILES AN HOUR" "ON A COMPLETELY DIFFERENT COURSE." "THE TWO ASTEROIDS SHATTER INTO MILLIONS OF FRAGMENTS." "BUT THIS FRAGMENT," "OVER SIX MILES ACROSS," "HAS A SPECIAL DESTINY." "IT'S A ROCK POISED TO CHANGE HISTORY." "THE PLANET'S REPTILIAN LORDS" "LIVE COMPLETELY UNAWARE OF WHAT'S HEADING THEIR WAY." "[ TRICERATOPS GRUNTING ]" "IN THE PACIFIC NORTHWEST," "MALE TRICERATOPS VIE FOR MATING RIGHTS." "[ TRICERATOPS ROARING ]" "INTIMIDATION DOES THE TRICK." "BUT THERE'S ANOTHER ENEMY WAITING IN THE WINGS." "[ DINOSAURS ROARING ]" "THE TRICERATOPS IS FAST AND WELL-ARMORED ENOUGH" "TO STAND A CHANCE AGAINST T. REX BUT NOT AGAINST TWO OF THEM." "THERE'S ENOUGH MEAT HERE TO FEED THEM BOTH FOR WEEKS," "BUT THEY MAY NOT HAVE THE TIME TO ENJOY IT." "A QUARTER OF A MILLION MILES UP" "IS THE EARTH'S LAST HOPE OF DEFENSE." "THE MOON HAS SAVED THE PLANET BEFORE." "ITS POCKMARKED SURFACE BEARS" "THE SCARS OF COUNTLESS COLLISIONS." "THIS CRATER, KNOWN AS TYCHO," "IS MORE THAN 50 MILES WIDE," "CREATED BY A ROCK" "ONLY HALF THE SIZE OF THE ONE THAT'S ON ITS WAY." "BUT THE MOON IS RARELY IN THE RIGHT PLACE AT THE RIGHT TIME." "NOTHING CAN STOP THE ASTEROID NOW." "IN WHAT IS TODAY CENTRAL MEXICO," "A HERD OF ALAMOSAURUS" "IS WANDERING THE PLAINS IN SEARCH OF FOOD." "EVEN BY DINOSAUR STANDARDS, THEY'RE HUGE." "70 FEET LONG AND A STAGGERING 40 FEET TALL," "ALAMOSAURUS WEIGH UP TO 30 TONS." "TO MAINTAIN THAT BULK," "THEY NEED TO EAT UP TO A TON OF LEAVES EVERY DAY." "BECAUSE SHE'S ON A CONSTANT SEARCH FOR FOOD," "WHEN IT'S TIME TO LAY HER EGGS, SHE DOESN'T NEST." "SHE SIMPLY LAYS EGGS IN GROUPS OF FIVE OR SIX" "TO IMPROVE THE CHANCES THAT SOME WILL SURVIVE." "UNDER NORMAL CONDITIONS," "ONLY ONE IN 3,000 WILL PRODUCE A MATURE ALAMOSAURUS." "BUT THE ODDS STACKED AGAINST THESE EGGS" "ARE ABOUT TO GET ASTRONOMICAL," "BECAUSE 2 TRILLION TONS OF ROCK IS RACING RIGHT AT THEM." "AS IT GETS CLOSER TO THE PLANET," "THE EARTH'S GRAVITATIONAL PULL GETS STRONGER," "AND THE ASTEROID ACCELERATES," "PAST 40,000 TO 45,000 MILES PER HOUR." "AS THE ASTEROID ENCOUNTERS ATMOSPHERE," "FRICTION TURNS IT INTO A FIREBALL" "SWOOPING OVER THE ATLANTIC AND AIMED AT MEXICO." "IT TAKES JUST FOUR MINUTES TO CROSS THE OCEAN." "IT CRUSHES AND SUPERHEATS THE AIR SURROUNDING IT," "TRANSFORMING GAS AND DEBRIS INTO WHITE-HOT PLASMA." "AT 35,000 DEGREES," "IT'S BURNING BRIGHTER THAN A MILLION SUNS." "THE DAY OF RECKONING IS HERE." "[ ALAMOSAURUS GROWLING ]" "Narrator:" "AFTER A JOURNEY LASTING 100 MILLION YEARS," "AN ENORMOUS CHUNK OF COSMIC ROCK" "IS APPROACHING THE END OF THE LINE." "AND THE END OF THE LINE IS EARTH." "THE ASTEROID'S TRAJECTORY IS SHALLOW." "IT FLIES IN AT ABOUT A 30-DEGREE ANGLE TO THE SURFACE." "THIS MEANS THE FULL BRUNT OF ITS DESTRUCTIVE POWER" "WILL BE THROWN TO THE NORTH OF THE IMPACT POINT." "500 MILES FROM GROUND ZERO," "THE ALAMOSAURUS HAVE NO WAY OF SEEING WHAT'S HEADED THEIR WAY." "[ ALAMOSAURUS ROARING ]" "THE SCORCHING LIGHT SEARS THEIR EYEBALLS," "BLINDING THEM." "AN EXPLOSIVE FORCE MORE POWERFUL" "THAN ALL THE NUCLEAR WEAPONS EVER BUILT" "HITS THE SHALLOW WATERS OF THE GULF OF MEXICO." "EARTH AND ROCK ARE HURLED SKYWARD" "AT 100,000 MILES AN HOUR." "IN A FRACTION OF A SECOND," "THE ENTIRE ASTEROID DISINTEGRATES INTO THE PLANET." "500 MILES FROM THE CRASH SITE," "THE AIR TEMPERATURE NOW REACHES 600 DEGREES " "HOT ENOUGH TO BOIL AWAY THE WATER IN THE DINOSAURS' SKIN." "ANYTHING DIRECTLY EXPOSED TO THE BLISTERING HEAT..." "IS SIMPLY BROILED ALIVE." "ON IMPACT, BOULDERS THE SIZE OF BUILDINGS BLAST INTO THE AIR." "BUT WHAT GOES UP..." "MUST COME DOWN." "HUNDREDS OF SURVIVING ALAMOSAURUS" "ARE BOMBARDED FROM ABOVE." "THE BLAZING PLUME BLASTS 100 MILES OVER THE IMPACT ZONE," "HIGH ENOUGH AND BRIGHT ENOUGH TO BE SEEN OVER THE HORIZON" "AN EIGHTH OF THE WAY AROUND THE WORLD." "FROM THEIR CLIFF-TOP ROOST," "A BREEDING PAIR OF QUETZALCOATLUS" "CAN SEE THE GLOW OF THE FIREBALL 3,000 MILES AWAY." "THE BODY COUNT BACK NEAR THE CRASH SITE IS IMMENSE." "MANY OTHER SPECIES OF DINOSAUR IN THE REGION" "SHARE THE ALAMOSAURUS' FATE." "MOST OF THE EGGS, TOO, HAVE BEEN DESTROYED." "AND YET THE EARTH IS A POWERFUL PROTECTOR." "BURIED IN THE COOL GROUND, SOME EGGS HAVE SURVIVED." "ON THE OTHER SIDE OF THE PLANET," "MONGOLIA IS 8,000 MILES FROM THE IMPACT." "FOR A FAMILY OF KRONOSAURUS," "IT'S BUSINESS AS USUAL AT A FAVORITE WATERING HOLE." "THEY CAN WEIGH 4 TONS AND GROW TO 40 FEET IN LENGTH." "BUT THEY'RE VEGETARIANS AND DOCILE," "EXCEPT WHEN THEY HAVE TO DEFEND THEMSELVES OR THEIR OFFSPRING." "[ GROWLING ]" "ARMED WITH A RAZOR-SHARP, OVERSIZED CLAW ON ITS HIND FEET," "SAURORNITHOIDES IS THE JACKAL OF THE CRETACEOUS PERIOD." "ITS BRAIN-TO-BODY-WEIGHT RATIO" "IS AMONG THE HIGHEST OF ANY DINOSAUR." "IT KNOWS BETTER THAN TO TAKE ON A FULL-GROWN KRONOSAURUS NOT WHEN THERE ARE EASIER TARGETS." "[ GRUNTING ]" "[ BELLOWS ]" "THE THIEF DOESN'T GET AS FAR AWAY FROM THE ENRAGED MOTHER" "AS IT SHOULD." "BUT KRONOSAURUS ISN'T MADE FOR FIGHTING." "AND THAT'S EXACTLY WHAT THE SAURORNITHOIDES IS COUNTING ON," "ESPECIALLY WHEN HE'S GOT BACKUP." "SPEED AND STRATEGY GIVE THESE SMALL HUNTERS THE EDGE." "BUT NEITHER GREAT SIZE NOR GREAT INTELLIGENCE" "IS ANY GUARANTEE OF SAFETY" "FROM THE KIND OF ENEMY THAT IS NOW APPROACHING." "[ DINOSAURS ROARING ]" "Narrator:" "AN IMMENSE BOULDER THE SIZE OF MOUNT EVEREST" "CRASHES INTO THE GULF OF MEXICO," "DRIVING ENTIRE SPECIES OF DINOSAURS TO EXTINCTION" "IN LESS THAN FIVE MINUTES." "BUT THE WORST IS STILL TO COME." "A FIREBALL RISES 100 MILES ABOVE GROUND ZERO." "70 BILLION TONS OF PULVERIZED STONE AND EARTH" "FILL THE UPPER ATMOSPHERE" "WITH A CLOUD OF MICROSCOPIC DUST AND GLASS," "AND IT'S SPREADING FAST." "THIS IS THE EJECTA CLOUD." "AS THE DUST SPREADS AT HIGH ALTITUDE," "TRILLIONS OF TINY PARTICLES RE-ENTER THE ATMOSPHERE." "THE FRICTION CREATES INTENSE HEAT " "A 15,000-DEGREE DUST CLOUD" "HEATING UP EVERYTHING BENEATH IT." "[ SCREECHES ]" "FROM THEIR CLIFF-TOP PERCH IN THE PACIFIC NORTHWEST," "THE MALE AND FEMALE QUETZALCOATLUS" "HAVE A CLEAR VIEW OF THE APPROACHING CLOUD." "MILLIONS OF VOLTS OF STATIC ELECTRICITY" "CHARGE THE CLOUD LIKE A GIANT BATTERY," "CREATING A VAST ELECTRICAL STORM." "SUPERHEATED ROCKS SHOWER THE VALLEY." "THERE'S NO WAY TO HIDE FROM A RAIN OF FIRE." "[ QUETZALCOATLUS SCREECHING ]" "THE MALE'S TATTERED WINGS CAN NO LONGER KEEP HIM ALOFT." "IF HIS MATE DOESN'T FIND SHELTER, SHE'LL BE NEXT." "THE EJECTA CLOUD CONTINUES TO SPREAD AT HIGH ALTITUDE." "8,000 MILES AWAY IN ASIA," "THE CLOUD ROLLS IN FROM THE EAST." "IN MONGOLIA, TEMPERATURES ON THE GROUND" "TICK UPWARDS A FEW DEGREES HOTTER EVERY SECOND." "AS THE AIR REACHES 120 DEGREES," "THE ONLY HOPE IS SHELTER." "[ GRUNTS ]" "[ BELLOWS ]" "AT 160 DEGREES," "SURVIVAL IS MEASURED IN MINUTES " "OVER 200 DEGREES, JUST SECONDS." "90 MINUTES AFTER IMPACT," "THE TEMPERATURE ON THE GROUND IN MONGOLIA" "PEAKS AT 300 DEGREES." "THE MICROCLIMATE OF A CAVE" "CAN KEEP A HANDFUL OF SURVIVORS COOL ENOUGH TO BREATHE," "BUT IT'S A REFUGE THAT HAS TO BE SHARED," "FORCING AN UNEASY PEACE BETWEEN SWORN ENEMIES..." "[ DINOSAURS GROWLING ] ...ONE THAT'S ALREADY FRAYING AT THE EDGES." "BACK IN THE PACIFIC NORTHWEST," "SMALL POCKETS OF DINOSAURS HANG ON." "FOR THE TRICERATOPS HERE," "THE HIGH TEMPERATURES AND HUMIDITY" "FORCE THEM TO KEEP MOVING." "FOR SCAVENGERS, THERE'S NO SHORTAGE OF FOOD." "[ SCREECHES ]" "BUT MOST ANIMALS CAUGHT BY THE EJECTA CLOUD" "AREN'T SO LUCKY." "AND THE AFTEREFFECTS OF IMPACT ARE JUST GETTING STARTED." "THE INTENSE HEAT OF THE EJECTA CLOUD" "HAS IGNITED FIRES " "BLAZES SO INTENSE THEY GENERATE THEIR OWN WINDS." "THE AIR PRESSURE PLUMMETS," "CREATING A VACUUM THAT SUCKS IN THE FLAMES." "THE FRONT OF THE FIRE BURNS HOTTEST AND FASTEST MOVING ACROSS THE VALLEY FLOOR AT NINE MILES AN HOUR." "T. REX CAN RUN TWICE THAT SPEED," "BUT IT CAN'T KEEP THE PACE UP FOREVER." "THE VALLEY BASIN IS NOW A FIRE STORM 1,800 DEGREES " "HOT ENOUGH TO MELT SOLID ALUMINUM." "THE PANICKED ANIMALS RACE UP THE VALLEY SLOPES." "BUT LARGE DINOSAURS HAVE NO PLACE TO HIDE." "[ DINOSAURS ROARING ]" "TIME IS RUNNING OUT." "Narrator:" "TWO HOURS AFTER THE ASTEROID IMPACT," "THE ENTIRE PLANET IS COVERED IN DUST AND SMOKE." "FIRES RAGE ACROSS THE WESTERN HEMISPHERE." "ANIMALS THAT FLY CAN ESCAPE THE FLAMES," "BUT THERE ARE FEW PLACES TO LAND AND ALMOST NOTHING TO EAT." "FROM ABOVE, WHAT WAS ONCE A LUSH VALLEY IS NOW A LIVING HELL." "8,000 MILES AWAY IN MONGOLIA," "THE TEMPERATURES ARE FINALLY DROPPING." "A HANDFUL OF ANIMALS REMAIN SAFELY HOLED UP IN THEIR CAVE." "THE RAVENOUS SAURORNITHOIDES" "CAN'T RESIST THE SIGHT OF AN EASY MEAL." "SOON, THE BRAVER KRONOSAURUS FOLLOW," "MAKING THEIR WAY BACK TOWARDS THE WATERING HOLE." "ONE STAYS NEAR THE PROTECTION OF THE CAVE." "[ BELLOWS ]" "IT SEEMS THE WORST IS OVER." "AS THE EJECTA BEGINS TO CLEAR," "THE PARTING CLOUDS REVEAL THE SHIFT IN TEMPERATURE" "IS THROWING EARTH'S WEATHER SYSTEMS INTO TURMOIL." "AND IN MONGOLIA," "POWERFUL WINDS ARE GATHERING" "BILLIONS OF TONS OF DUST AND SAND." "A DUST STORM FORMS AS HOT AIR RISES." "THERMAL IMAGING SHOWS HOW IT BUILDS," "WHIPPING UP LOOSE PARTICLES OF SAND AND DUST" "AND GAINING ENERGY FROM THE HEAT OF THE SAND ITSELF." "THE 300-DEGREE TEMPERATURES THAT BAKED MONGOLIA" "TURN A COMMON WEATHER PHENOMENON INTO A SUPERSTORM." "AS IT HITS," "THE SAURORNITHOIDES ARE SMALL ENOUGH TO CROUCH FOR COVER." "BUT THE KRONOSAURUS ARE OUT IN THE OPEN." "THE HARDER THEY STRUGGLE" "AND THE DEEPER THEY GASP FOR OXYGEN," "THE MORE SAND FILLS THEIR LUNGS UNTIL FINALLY THEY CAN'T BREATHE." "THE SUPERSTORM ENGULFS MUCH OF THE CONTINENT." "IT'S HOURS BEFORE THE WINDS DIE DOWN." "THE LAST KRONOSAURUS, PROTECTED ONCE AGAIN BY THE CAVE," "HEADS TO THE WATERING HOLE ON HER OWN." "HALFWAY THERE, SHE FINDS SHE'S THE LAST OF THE HERD." "BUT SHE'S NOT THE LAST REMAINING DINOSAUR IN THE NEIGHBORHOOD." "[ BELLOWS ]" "HUDDLED CLOSE TO A KRONOSAURUS CORPSE," "THE SAURORNITHOIDES WAS SHELTERED" "FROM THE WORST OF THE STORM." "[ SAURORNITHOIDES SNIFFING, GRUNTING ]" "BUT THE SAND HAS SWALLOWED THEIR MEAL." "INSTINCT DRIVES THEM" "BACK TO THEIR PRIME HUNTING SPOT " "THE WATERING HOLE," "WHERE THE LAST SURVIVING KRONOSAURUS" "IS TAKING IN THE MUCH-NEEDED FLUID." "THE SAURORNITHOIDES ARE DESPERATE FOR FOOD." "ONE HAS THE CONFIDENCE TO ATTACK." "ITS PREY IS STILL TOO EXHAUSTED TO RUN." "BUT THIS TIME, SIZE DOES MATTER." "THE REMAINING SAURORNITHOIDES MOVES IN." "BUT IT HAS NO INTENTION OF MAKING A RUN" "AT THE KRONOSAURUS NOT WHEN FATE OFFERS IT A MEAL THAT CAN'T FIGHT BACK." "A WEEK AFTER IMPACT," "FOOD IS IN VERY SHORT SUPPLY ACROSS THE ENTIRE PLANET." "LIFE IS HARDEST FOR THE PLANT EATERS." "[ TYRANNOSAURUS REX ROARING ]" "THE CARNIVORES ARE MORE FORTUNATE." "THEY CAN EAT THE HERBIVORES." "[ ROARS ]" "BUT TWO TRICERATOPS ARE A LITTLE TOO MUCH TO TAKE ON." "HUNGER DRIVES THE GIANT HERBIVORES" "TOWARD THE PACIFIC COAST." "THE DEVASTATION REACHES ALL THE WAY TO THE SEA." "BUT GEOGRAPHY HAS A WAY OF PROTECTING CERTAIN PLACES" "FROM CATACLYSMIC EVENTS " "IN THIS CASE, AN ISLAND," "APPARENTLY UNTOUCHED BY THE SURROUNDING DESOLATION." "THERE MAY STILL BE FOOD HERE." "THE FEMALE QUETZALCOATLUS HAS BEEN FLYING FOR THREE DAYS." "[ SCREECHING ]" "SHE'S WEAK AND IN DESPERATE NEED OF FOOD." "FROM 1,000 FEET UP, THE ISLAND COMES INTO VIEW." "BUT ALL IS NOT AS PEACEFUL AS IT SEEMS." "DEEP BELOW THE SURFACE," "THE OCEAN FLOOR WAS SHAKEN BY THE ASTEROID'S INITIAL IMPACT." "SEDIMENTARY ROCK DISINTEGRATES UNDER THE STRAIN" "AND COLLAPSES HUNDREDS OF FEET INTO THE OCEAN FLOOR." "SEA LEVEL PLUNGES, TRIGGERING A MASSIVE SWELL." "AT THE COAST, THE OCEAN IS DRAGGED BACK HUNDREDS OF FEET." "THE PATH TO THE ISLAND IS SUDDENLY DRY LAND." "SHELTERED FROM THE EJECTA BY SEA MIST" "AND PROTECTED FROM FIRES BY THE SURROUNDING OCEAN," "THE ISLAND HAS ALL THE FOOD THEY NEED." "IT SEEMS TOO GOOD TO BE TRUE." "[ GRUNTS ]" "THE ASTEROID HAS AWAKENED" "THE OCEAN'S MOST DESTRUCTIVE FORCE " "A MEGA TSUNAMI." "Narrator:" "A MONSTER WAVE 300 FEET HIGH," "ONE OF THE TALLEST IN THE HISTORY OF THE PLANET " "THIS IS A MEGA TSUNAMI." "[ DINOSAURS ROARING ]" "THE AVALANCHE OF WATER LEAVES COUNTLESS DEAD IN ITS WAKE." "[ GRUNTING ]" "BUT AS DEVASTATING AS THE FIRST WAVE OF DISASTERS IS," "THERE'S MORE TO COME..." "BECAUSE WHEN A ROCK SIX MILES ACROSS" "SLAMS INTO THE EARTH AT 45,000 MILES PER HOUR," "IT SHOOTS A MILLION MEGATONS OF ENERGY" "STRAIGHT INTO THE GROUND." "SEISMIC SHOCK WAVES RIPPLE THROUGH THE PLANET." "TECTONIC PLATES SHEAR AND TEAR." "DEEP INSIDE THE PLANET," "THEY TRIGGER MOLTEN ROCK TO FORCE ITS WAY TO THE SURFACE" "THROUGH NEWLY FORMED FRACTURES UNTIL IT EXPLODES FROM THE EARTH'S CRUST" "IN VIOLENT VOLCANIC ERUPTIONS." "THE SEISMIC WAVES AWAKEN DORMANT VOLCANOES AROUND THE WORLD," "ADDING TO THE DEBRIS CLOUDS OF DUST AND TOXIC GASES" "THAT SURROUND THE GLOBE." "THE SHROUD IS ALREADY MANY MILES DEEP," "STOPPING LIGHT AND WARMTH REACHING THE EARTH'S SURFACE." "THE PLANET PLUNGES FURTHER INTO A NUCLEAR WINTER." "IN THE DAYS AND WEEKS THAT FOLLOW," "FEW SIGNS OF DINOSAURS REMAIN." "HERE IN MONGOLIA," "THE STARVING KRONOSAURUS STAYS NEAR THE CAVE" "THAT HAS SAVED IT TWICE IN THE PAST." "BUT THE LAST KRONOSAURUS DOESN'T FALL VICTIM TO STARVATION." "BUBBLING TO THE SURFACE" "IS ONE OF NATURE'S MOST TOXIC GASES " "HYDROGEN SULFIDE." "RELEASED FROM DEEP UNDERGROUND BY VOLCANIC ACTIVITY," "THE GAS PARALYZES THE LUNGS, MAKING ESCAPE IMPOSSIBLE." "THEN IT KILLS BY SUFFOCATION." "WHAT WAS ONCE A REFUGE..." "IS TRANSFORMED INTO A DEATH TRAP." "THE LAST DINOSAUR IN THIS PART OF MONGOLIA IS DEAD." "IN THE PACIFIC NORTHWEST," "JUST A HANDFUL OF DINOSAURS PATROL THE GRAY WASTELAND." "AN ANKYLOSAURUS, SEVERELY WEAKENED BY HUNGER," "SEARCHES THE CHARRED TERRAIN FOR SOMETHING TO EAT." "25 FEET LONG AND WEIGHING 4 TONS," "THIS HEAVILY ARMORED HERBIVORE" "IS USED TO GETTING NEARLY 300 POUNDS OF FOOD EVERY DAY." "ALL IT CAN FIND NOW IS A SMALL BUSH." "[ DINOSAURS ROARING ]" "AND EVEN THAT WON'T COME WITHOUT A FIGHT." "SUDDENLY, HUNGER ISN'T THEIR BIGGEST PROBLEM." "HE IS." "[ DINOSAURS ROARING ]" "Narrator:" "IN THE PACIFIC NORTHWEST," "WITH FOOD SOURCES DISAPPEARING," "STARVING GIANTS FIGHT FOR EVERY CALORIE." "IT'S TWO OF THIS WORLD'S BEST ARMORED WARRIORS" "VERSUS A HUNGRY CARNIVORE THAT WON'T TAKE NO FOR AN ANSWER." "THE ANKYLOSAURUS'S MAIN DEFENSE WEAPON IS A HEAVY TAIL CLUB." "BUT IT'S TOO WEAK TO GET IN A GOOD SHOT." "THE DINOSAURS THAT OUTLAST" "THE EJECTA, FIRE STORMS, AND POISON GAS" "ULTIMATELY FALL VICTIM TO THE DEMANDS" "OF THEIR OWN MASSIVE BODIES." "MEXICO, 500 MILES FROM THE POINT OF IMPACT " "THE VERY FIRST LANDMASS TO FEEL THE FORCE" "OF THE ASTEROID'S STRIKE A REGION THAT HAS SUFFERED WAVE UPON WAVE OF VIOLENCE YET EVEN NOW, LIFE REMAINS " "A LAST SURVIVING ALAMOSAURUS EGG." "BURIED SAFE WITHIN THE SOIL," "A CHICK HAS SURVIVED THE BARRAGE OF DESTRUCTION." "AND HE'S NOT ALONE." "[ GRUNTING ]" "ALL AROUND THE WORLD," "SMALL HANDFULS OF DINOSAURS TRY TO START OVER." "BUT THEIR SPECIES ARE ALREADY DEAD BECAUSE TO SURVIVE," "ANY SPECIES NEEDS TO MAINTAIN A CRITICAL MASS OF POPULATION." "FALL BELOW THAT THRESHOLD," "AND THERE'S NO WAY TO CLIMB BACK FROM CERTAIN EXTINCTION." "OUT OF THE RUINS, NATURE STARTS OVER." "NEW GROWTH EMERGES," "AND ONE PLANT IN PARTICULAR -- FERNS." "THEY CARPET THE PLANET IN GREEN," "THEN GIVE WAY TO FORESTS," "BREATHING OXYGEN AND LIFE INTO THE PLANET," "SETTING THE STAGE FOR A NEW ERA BECAUSE WAITING IN THE WINGS" "ARE CREATURES WHOSE DEVELOPMENT" "HAD LONG BEEN THWARTED BY THE DINOSAURS MAMMALS." "THEY MULTIPLY AND DIVERSIFY 10,000 SPECIES EXPLODING ACROSS THE PLANET." "[ DOGS BARKING ]" "BUT ONE VERY IMPORTANT SPECIES BRANCHES OFF FROM ITS RELATIVES" "AND COMES DOWN FROM THE TREES." "THEY WALK ON TWO LEGS," "EVOLVE BIGGER BRAINS," "AND EVENTUALLY..." "RULE THE PLANET." "THEY'LL RESHAPE THE WORLD," "BUILDING CITIES THAT TOUCH THE SKY VEHICLES THAT CAN LEAVE THE PLANET..." "AND WEAPONS THAT CAN DESTROY IT." "BUT NONE OF IT COULD HAVE BEEN POSSIBLE" "IF A CHANCE COLLISION IN SPACE 165 MILLION YEARS AGO" "HADN'T SENT AN ASTEROID HURTLING TOWARD EARTH" "AND DOOMED THE DINOSAURS TO EXTINCTION." "ONLY BECAUSE THEY DIED CAN HUMAN BEINGS LIVE."