>> WHAT WOULD HAPPEN IF EVERY HUMAN BEING ON EARTH DISAPPEARED? THIS ISN'T THE STORY OF HOW WE MIGHT VANISH. IT IS THE STORY OF WHAT HAPPENS TO THE WORLD WE LEAVE BEHIND. IN THIS EPISODE OF<i> LIFE AFTER PEOPLE:</i> INVASIVE PLANTS AND PREDATORS ARE READY TO STRIKE. PYTHONS AND ALLIGATORS CLASH IN DEADLY TURF BATTLES. WATER WEEDS GROW LIKE CANCERS, STEALING VITAL SUPPLIES OF OXYGEN. AND DUST STORMS THE SIZE OF MOUNTAINS HOBBLE DEFENSELESS CITIES. THIS IS JUST PART OF THE JOURNEY THAT WILL TAKE US TO THE FUTURE OF CITIES ON THE EDGE OF CIVILIZATION, AS WELL AS HAUNTING SIGHTS ALREADY DEVOID OF MAN. WELCOME TO EARTH: POPULATION ZERO. HUMANS HAVE ALWAYS BATTLED INVADERS FROM NATURE, KEEPING THOUSANDS OF INVASIVE PLANTS AND ANIMALS AT BAY. BUT WITHOUT PEOPLE TO FIGHT THEM, THEY OVERRUN OLD HABITATS. HOW LONG WILL IT BE UNTIL THESE INVASIVE SPECIES CONQUER THE WORLD? >> WITHOUT US, THE IMMEDIATE CHANGE IN THE NATURAL WORLD WOULD BE-- YOU'D HAVE TO CALL IT EXPLOSIVE. IT'S ALMOST DIFFICULT TO IMAGINE THE SCALE AND THE MAGNITUDE AT WHICH IT WOULD TAKE PLACE. ONE DAY AFTER PEOPLE. THE INVADERS ARE ON THE MOVE. IN THE MORE THAN 2,500 SQUARE MILES OF MARSHES AND SWAMPS OF FLORIDA'S EVERGLADES, THE ANCIENT DOMAIN OF THE ALLIGATORS IS ATTACKED BY OTHER COLD-BLOODED GIANTS: BURMESE PYTHONS. IN 2008, MORE THAN 300 PYTHONS WERE CAPTURED IN THE EVERGLADES, JUST A SMALL FRACTION OF THE ESTIMATED 30,000 OF THEM BELIEVED TO BE SLITHERING THROUGH THE SWAMPS. BURMESE PYTHONS WERE FIRST BROUGHT TO FLORIDA AS EXOTIC PETS. BUT MANY WERE SET LOOSE BY OWNERS WHO COULD NO LONGER CONTROL THE RAPIDLY GROWING SNAKES. >> YOU START OFF FEEDING THEM MICE, THEN RATS, THEN RABBITS, AND THEN YOU HAVE TO FIGURE OUT WHAT YOU WANT TO FEED THEM-- 5 OR 6 RABBITS, OR WHERE DO YOU GET FOOD FOR YOUR SNAKE? >> THE FLESH-EATING INVADERS, SOME AS LONG AS 25 FEET, STEAL PREY FROM THE NATIVE ALLIGATORS. IN THE TIME OF HUMANS, TEAMS OF GOVERNMENT TRAPPERS TRIED TO CATCH AND REMOVE THEM. >> WITHOUT PEOPLE, THERE'LL BE NO, NO CHECK. >> WITH NO HUMANS TO CONTROL THEIR SPREAD, CAN ANYTHING STOP THE PYTHONS? THERE ARE MORE THAN 4,000 INVASIVE SPECIES IN THE UNITED STATES ALONE. NOT JUST ANIMALS, BUT KILLER PLANTS AS WELL. >> AN INVASIVE SPECIES IS AN ORGANISM, WHETHER IT'S A PLANT OR AN ANIMAL, THAT COMES FROM ANOTHER REGION, USUALLY ANOTHER CONTINENT. AND THEY HAVE NO NATURAL PREDATORS, COMPETITORS, OR PARASITES IN THE NEW HABITAT THAT THEY OCCUPY. AND SO THEY'RE ABLE TO EXPAND VERY QUICKLY AND BECOME INVASIVE. >> JUST ONE WEEK AFTER PEOPLE, RIVERS AND LAKES FROM FLORIDA TO TEXAS ARE DYING, AS INVASIVE WEEDS FROM SOUTH AMERICA MULTIPLY WITH NO HUMANS TO CLEAR THEM AWAY. ONE PLANT, THE WATER HYACINTH, IS A PRETTY PURPLE FLOWER, WITH A DARK SIDE. >> IT SUCKS THE OXYGEN OUT OF THE WATER, WHICH DOESN'T ALLOW NATIVE SPECIES, ESPECIALLY FISH, TO SURVIVE AND THRIVE, SO IT COULD DOUBLE ITS POPULATION IN ANY GIVEN HABITAT IN A WEEK TO TWO WEEKS. >> ONLY PEOPLE COULD CONTROL THEIR SPREAD. SO NOW THE INVASIVE SPECIES ARE WINNING THE BATTLE-- BY FORFEIT. SOME OF THE MOST AGGRESSIVE INVADERS ARE ALSO THE SMALLEST. AS MANY AS 400,000 SPECIES OF MICROSCOPIC BACTERIA AND MOLD SPORES ATTACK EVERYTHING THAT WAS ONCE ALIVE. MANY OF THESE ORGANISMS ARE SO SMALL, 250,000 COULD FIT ON THE HEAD OF A PIN, AND THEY LIVE EVERYWHERE. THEY BEGIN TO DEVOUR THE ORGANIC MATTER: THE FOOD, THE WOOD, THE CARCASSES OF ANIMALS LEFT BEHIND IN THE ABSENCE OF MAN. PREDATORS OF THE DEAD, LARGE AND SMALL, ARE FEASTING. >> USUALLY THE FIRST INSECTS THAT'LL BE ATTRACTED TO THE BODY WITHIN A MATTER OF MINUTES ARE FLIES. THEY CAN SMELL A DEAD BODY FROM MILES AWAY. AFTER A FEW DAYS, YOU START HAVING OTHER INSECTS THAT ARE MORE CARNIVOROUS. >> OTHER VERMIN ATTACK LIVING ANIMALS, INCLUDING MILLIONS OF DOGS WHO DEPENDED ON HUMANS TO KEEP THEM HEALTHY AND WHO NOW MUST FEND FOR THEMSELVES. SOME BREEDS FARE BETTER THAN OTHERS. 10 DAYS... INTO A LIFE AFTER PEOPLE, SOME GREYHOUNDS HAVE ESCAPED FROM THE MORE THAN 40 DOGTRACKS AROUND THE UNITED STATES. IN FLORIDA, ONE GROUP OF THE HOUNDS NOW ROAMS FREE. OFTEN FED RAW MEAT TO INCREASE THEIR COMPETITIVE INSTINCT WHEN CHASING MECHANICAL RABBITS, ESCAPED GREYHOUNDS NOW HUNT REAL RABBITS... AS WELL AS RATS. THESE DOGS TRACK WITH THEIR EYES, NOT THEIR NOSES. >> WELL, GREYHOUNDS ARE SIGHT HOUNDS. AND THEY'RE USED TO HUNTING DOWN THEIR PREY BY RUNNING. [DOGS BARK] >> THEY ALSO SCAVENGE FOR FOOD. BUT THIS OFTEN REQUIRES COOPERATION. AND GREYHOUNDS HAVE BEEN TRAINED TO BEAT THEIR COMPETITORS, AT ANY COST. >> THE DOGS WOULD BEGIN TO COMPETE FOR THAT RESOURCE BETWEEN EACH OTHER. SO THERE'S GOING TO BE AGGRESSION, LOTS OF FIGHTING. >> THE STREAMLINED GREYHOUNDS HAVE THIN SKINS AND ARE EASILY INJURED. FOR THEM, THE RACE TO SURVIVE WILL BE SHORT-LIVED. WHILE GREYHOUNDS CLASH IN FLORIDA, TINY INVADERS ATTACK NEW YORK. THE ASIAN LONGHORN BEETLE ARRIVED IN NEW YORK FROM CHINA IN THE MID 1990s, PROBABLY STOWING AWAY IN SOME CARGO. THEY QUICKLY STARTED CHOMPING ON THE TREES OF NEW YORK CITY, REQUIRING A MASSIVE ERADICATION EFFORT. >> THEY'VE GOT THE BEETLE CORNERED, THEY'VE GOT IT DOWN ON ITS LAST OF ITS SIX LEGS. BUT, IF PEOPLE SUDDENLY DISAPPEARED, THAT BEETLE WOULD AGAIN BEGIN TO SPREAD. AND OF THE 5 MILLION TREES PRESENTLY IN NEW YORK CITY, 2.4 MILLION OF THEM ARE SUSCEPTIBLE TO THE ASIAN LONGHORN BEETLE. >> THE LARVA OF THESE INCH-AND-A-HALF-LONG INSECTS ARE MINIATURE BIOFUEL FACTORIES. FUNGUS IN THEIR GUT SOMEHOW HELPS THEM CONVERT WOOD INTO ENERGY, AN ATTRIBUTE SO UNIQUE THAT HUMAN SCIENTISTS STUDIED THEM FOR CLUES ABOUT HOW TO DERIVE ETHANOL FROM TREES. >> ONCE THEY GET INTO THE HEART OF THE TREE, THEY START BORING ALONG THE LENGTH OF THE BRANCHES, AND THEY CREATE THESE DIME-SIZED HOLES RUNNING ALONG THE LENGTH. NOW YOU CAN IMAGINE, IF YOU'VE GOT ONE DIME-SIZED HOLE THROUGH A 12-INCH BRANCH OR TRUNK, IT'S NOT A BIG DEAL. YOU GET 30 OF THEM, AND ALL OF A SUDDEN, THAT TRUNK IS A LOT WEAKER. YOU GET 50 OR AND IT'S HANGING ON BY A FEW SHREDS OF WOOD, AND THE FIRST SNOWSTORM OR WINDSTORM THAT COMES ALONG KNOCKS YOUR TREE DOWN. >> INVASIVE SPECIES AND EXTREME FORCES BEGIN TO RESHAPE CITIES AROUND THE WORLD. FROM INDIA TO CHINA, FROM THE BEACHES OF MIAMI TO THE OUTER REACHES OF THE FLORIDA KEYS, AND RIGHT OVER THE EDGE OF THE GRAND CANYON. ACROSS THE DESERT, PHOENIX, ARIZONA, WILL FACE A CASCADING SERIES OF DISASTERS. ONE MONTH AFTER PEOPLE. THE DISASTER BEGINS AS PHOENIX IS INVADED BY A HEAT WAVE SET IN MOTION BY THE PEOPLE WHO ONCE LIVED HERE. BY PAVING THE DESERT, THE BUILDERS OF PHOENIX INCREASED THE AREA'S AVERAGE TEMPERATURE BY 15 DEGREES FAHRENHEIT. >> IT'S BEEN AS HOT AS 122 DEGREES HERE, IN PHOENIX, AT OUR AIRPORT, WITH THE TARMAC JUST BLAZING. >> CONCRETE ABSORBS ABOUT 60% OF THE SUN'S HEAT AND LIGHT. BUT ASPHALT CAN ABSORB 95%, AND BECAUSE OF ITS DENSITY, RETAINS MUCH OF THAT HEAT EVEN AFTER DARK. >> WE HAVE WHAT WE CALL AN URBAN HEAT ISLAND. WHEN THE SUN GOES DOWN AND THAT AIR IS TRYING TO LIFT FROM THE PAVEMENT, IT STILL STAYS REALLY, REALLY WARM. >> THAT HEAT SPEEDS UP THE EVAPORATION OF THE AREA'S PRECIOUS SUPPLY OF WATER. IN THE TIME OF HUMANS, PEOPLE MADE THE DESERT BLOOM WITH TREATED WASTE WATER. >> THIS LAKE BEHIND US IS A MANMADE LAKE, BUILT BY BULLDOZERS COMING IN LAYING DOWN RUBBER OR PLASTIC MATERIALS, AND THEN ADDING MORE WATER TO KEEP THE LAKE AT A CONSTANT LEVEL. SO THIS IS THE WATER THAT COMES FROM YOUR DISHWASHERS, YOUR SHOWER, YOUR SINKS. IT GOES TO THE TREATMENT PLANT, AND THEN IT IS TREATED AND THEN USED FOR LANDSCAPING, FOR IRRIGATION, AND DISCHARGED ALSO TO MANY OF THE RIVERS. >> BUT WITHOUT PEOPLE, THE WASTE-WATER PLANTS HAVE ALL SHUT DOWN. >> THINGS ARE GOING TO DIE, AND IT'S GOING TO GET PRETTY BROWN AROUND HERE VERY QUICKLY. >> IF THE WASTE-WATER TREATMENT PLANTS STOPPED OPERATING, IN A PHOENIX WITHOUT PEOPLE, THOUSANDS OF THESE MANMADE LAKES WOULD DRY UP WITHIN A MATTER OF WEEKS. >> 6 MONTHS AFTER PEOPLE. THE PHOENIX LAKES HAVE EVAPORATED. AND THE RIVERS FOLLOW. >> THE RIVERBEDS WILL BE SO DRY THAT THE SAND WILL BLOW AWAY AND THE RIPARIAN VEGETATION, THE TREES, THE ANIMALS, WOULD DIE FROM LACK OF WATER. IN A WORLD WITHOUT PEOPLE, THE DESERT WILL REGAIN ITS TERRITORY. INTO A LIFE AFTER PEOPLE. ALLIGATORS STILL RULE THE EVERGLADES. BUT THE INVASION OF BURMESE PYTHONS IS HEATING UP. AND AS HISTORY SHOWS, PYTHONS HAVE THE ADVANTAGE OF UNUSUAL SIZE. >> THE PYTHONS CAN GET VERY LARGE, 25 FEET IN LENGTH. THEY EAT JUST ABOUT ANYTHING THEY CAN CATCH. >> ANYTHING INCLUDES ALLIGATORS. IN 2005, RESEARCHERS IN THE EVERGLADES DISCOVERED THE AFTERMATH OF A GRISLY ATTACK, IN WHICH AN 8-FOOT ALLIGATOR WAS EATEN BY A 14-FOOT BURMESE PYTHON. >> THAT SAYS SOMETHING. IF THIS PYTHON IS SO HUNGRY THAT IT'S GONNA EAT AN 8-FOOT ALLIGATOR, ONLY 6 FEET LESS THAN ITS LENGTH, THEN IT'S PRETTY HUNGRY. >> BUT ALLIGATORS AREN'T GIVING UP WITHOUT A FIGHT. >> WHAT HAPPENED IN THAT IMAGE WAS THE ALLIGATOR WAS EATEN. IT WAS SUCH A HUGE AND UNCHARACTERISTICALLY LARGE MEAL, THIS PYTHON COULDN'T MOVE AFTER HE ATE IT. AND ANOTHER ALLIGATOR CAME ALONG AND BIT A HOLE IN THE PYTHON. >> A YEAR AFTER PEOPLE, THE 500,000 NATIVE ALLIGATORS STILL OUTNUMBER THE 30,000 INVASIVE PYTHONS. BUT THEY WILL NOT DO SO FOREVER. >> EVENTUALLY THE PYTHONS WILL OUTGROW THE ALLIGATOR AND BECOME OUR TOP PREDATOR. >> ALL AROUND THE WORLD, INVASIVE PREDATORS AND EXTREME FORCES TRANSFORM OUR CITIES. IN SHANGHAI, CHINA, THE ORIENTAL PEARL TOWER RISES 1,535 FEET INTO THE SKY ALONG THE HUANGPU RIVER. IT IS THE THIRD TALLEST TV AND RADIO TOWER IN THE WORLD. IT HOUSED A HOTEL, A SHOPPING MALL, AND A REVOLVING RESTAURANT. IN THE TIME OF HUMANS, MORE THAN 3,000 HIGH-RISES WERE BUILT IN SHANGHAI IN LESS THAN 20 YEARS. BY 2003, THE WEIGHT OF THE BUILDINGS WAS MAKING SHANGHAI SINK BY MORE THAN 1/2 INCH A YEAR. IN A LIFE AFTER PEOPLE, AN INVASION OF WATER FROM THE RIVER MAY BE THE TOWER'S GREATEST THREAT. 5 YEARS AFTER PEOPLE. LIKE SHANGHAI, MIAMI'S FATE IS TIED TO AN INVASION OF WATER. BENEATH THE WAVES THAT ARE EATING AWAY AT MIAMI'S COASTLINE, DOLPHINS THAT ONCE SWAM AMONG HUMANS WILL LEARN TO USE REMNANTS OF HUMAN CIVILIZATION IN THEIR NEW LIVES. >> DOLPHINS HAVE USED HUMAN DEBRIS THAT THEY FIND TO GO FISHING THROUGH THE BOTTOM MUD, LOOKING FOR CRUSTACEANS. >> THEY MAY USE OUR DEBRIS AS TOOLS, BUT WILL THEIR EXPERIENCE WITH HUMANS LIVE ON IN OTHER WAYS? MEANWHILE, DOWNTOWN MIAMI HAS A LOT OF NEW TENANTS. BIRDS HAVE TAKEN OVER APARTMENT BUILDINGS, SEEKING SECURE PLACES TO LAY THEIR EGGS. CHIMPANZEES HAVE ESCAPED FROM A LOCAL ZOO AND HAVE FOLLOWED THE BIRDS INTO THE TOWER, WHERE THEY FEAST ON THEIR EGGS. THIS MAY SET THE STAGE FOR A STARTLING EVOLUTIONARY BREAKTHROUGH. WHILE MOST CHIMPANZEES MIGHT GREEDILY EAT EVERY EGG, A FEW COULD TAKE A MORE LONG-RANGE APPROACH. >> ALL YOU'D NEED IS ONE LITTLE BREAKTHROUGH, A BRILLIANT CHIMP, WHO SAID... LET'S LET THE BIRDS KEEP ONE SET OF EGGS. >> BY DOING THIS, THE CHIMPS ENSURE THAT NEW GENERATIONS OF BIRDS WILL HATCH AND CONTINUE TO SUPPLY THEM WITH EGGS. THE CHIMPS ALSO PROTECT THEIR BIRDS FROM THE FERAL CATS WHO HUNT IN THE BUILDING'S HALLWAYS. [CHIMPANZEE SCREECHING] >> IF THEY PASSED ON THAT TRAIT OF DEFENDING THE TOWERS AND PROTECTING THE BIRDS AND ONLY TAKING AS MUCH AS THEY NEEDED WHILE LETTING THE BIRDS THRIVE, THEN THIS TRIBE MIGHT START DOWN A ROAD THAT COULD RAPIDLY EVOLVE. >> AND SO APES TAKE THE FIRST STEPS TOWARD ANIMAL HUSBANDRY, ONE OF THE BASIC ASPECTS OF HUMAN CIVILIZATION, AND A KEYSTONE TO THE DEVELOPMENT OF HIGHER INTELLIGENCE. 10 YEARS AFTER PEOPLE. PHOENIX IS BONE-DRY. AND THE SURROUNDING DESERT THREATENS TO WIPE IT OFF THE MAP. THIS MAY HAVE HAPPENED BEFORE AND LED TO THE END OF ANOTHER CIVILIZATION. MODERN PHOENIX WAS BUILT ON A 600-MILE COMPLEX OF IRRIGATION DITCHES LEFT BY NATIVE AMERICANS CALLED THE HOHOKAM, WHO DISAPPEARED AROUND THE YEAR 1400. >> THE DISAPPEARANCE OF THE HOHOKAM PEOPLE STILL REMAINS A MYSTERY. WHAT IS BELIEVED IS THAT THERE WAS EITHER A DROUGHT, A MASSIVE FLOOD, OR A FAMINE THAT HAPPENED AND COMPLETELY WIPED THESE PEOPLE OFF THE FACE OF THE PLANET. >> A POPULATION THAT MAY HAVE BEEN AS HIGH AS 50,000 PEOPLE COMPLETELY DISAPPEARED. NOW, THE REMNANTS LEFT BY PHOENIX' 1.5 MILLION PEOPLE ARE VULNERABLE TO THE SAME EPIC FORCES. PHOENIX FACES RECURRENT INVASIONS FROM SUMMERTIME TORRENTS OF SOIL, SAND, AND DUST CALLED BY THE ARABIC NAME FOR SANDSTORM: HABOOB. >> A HUGE DUST STORM, LIKE WHAT YOU ONLY SEE IN THE MOVIES, BUT IT HAPPENS HERE IN PHOENIX. >> A HABOOB CAN BE AS WIDE AS 60 MILES AND AS TALL AS 3,500 FEET. IMAGINE CLEAR SKIES, LOOKING OFF IN THE DISTANCE, AND SEEING A WALL OF BROWN. AND THEN, ALL OF A SUDDEN, YOU FIND YOURSELF IN THE MIDST OF DARKNESS. YOU HAVE DUST, ROCKS, SAND, WHAT LOOKS LIKE A BROWN CLOUD. >> MANMADE RIVERS AND IRRIGATION CANALS HAVE LONG VANISHED. THE TOPSOIL IS DRY AND LOOSE, WHICH ADDS MORE DUST TO THE WIND AND MAKES DUST STORMS IN A LIFE AFTER PEOPLE MORE DAMAGING THAN BEFORE. >> IMAGINE PHOENIX WITHOUT PEOPLE WHEN ONE OF THESE DUST STORMS COME THROUGH. WE HAVE THESE MASSIVE BUILDINGS IN CENTRAL PHOENIX. THEY STAND HUNDREDS OF FEET TALL. THE BUILDINGS WOULD BE BLOWN OUT BY ROCKS. >> ACRES OF DUST INVADE THE BROKEN BUILDINGS. [GLASS SHATTERING] OFFICE FLOORS BECOME DESERTS. BUT THEY'RE ONLY DRY FOR A LITTLE WHILE, BECAUSE AFTER THE DUST STORMS... COME THE MONSOON RAINS, TRIGGERED BY THE HEAT RISING FROM THE PHOENIX PAVEMENT. >> WHEN THE MONSOONS COME IN THE SUMMER, IT'S VERY DRAMATIC. THERE'S MINI TORNADOS, DOWNDRAFTS FROM ALL THESE BIG STORMS, THAT CAN RIP OUT ALL OF THESE TREES IN A MATTER OF MOMENTS. >> THE DRIVING RAINS MIX WITH THE SAND AND DUST... FILLING THE BROKEN BUILDINGS WITH MUD. IN THE TIME OF HUMANS, EMERGENCY SERVICES WOULD'VE CLEARED THE DEBRIS. WITH PEOPLE GONE, MUD FILLS THE OFFICES OF PHOENIX' BUSINESS DISTRICT. THIS CREATES ANOTHER PROBLEM. MUD IS HEAVIER THAN DIRT. AND IF THERE IS TOO MUCH MUD, THE BUILDINGS CAN'T SURVIVE MUCH LONGER. 20 YEARS AFTER PEOPLE. GIANT SWATHS OF MIAMI ARE BEING BURIED BY AGGRESSIVELY GROWING INVASIVE PLANTS. >> BRAZILIAN PEPPER WAS BROUGHT IN BECAUSE IT'S RED AND GREEN, FOR CHRISTMASTIME. SO IT WAS BROUGHT IN AS AN ORNAMENTAL PLANT. UNFORTUNATELY, THE BIRDS LIKE TO EAT ITS SEEDS AND DISPERSE IT. >> WITH NO PEOPLE TO STOP ITS SPREAD, THE CHRISTMAS DECORATION IS A YEAR-ROUND THREAT TO CITIES. >> IN LIFE WITHOUT HUMANS, IN 20 YEARS, YOU MAY NOT EVEN BE ABLE TO SEE THE HOUSES BEHIND THE BRAZILIAN PEPPER, WHICH GROW TALL ENOUGH TO OVERTOP HOUSES. THE MIAMI AREA WOULD REALLY LOOK LIKE A JUNGLE. >> THE BRAZILIAN PEPPER IS JOINED IN ITS ATTACK BY INVADING WAVES OF A CLIMBING VINE FROM AUSTRALIA CALLED LYGODIUM, WHICH CAN GROW TO 100 FEET. >> IN THE ABSENCE OF PEOPLE, WITH TIME, WEATHERING WOULD MAKE CRACKS IN ALL KINDS OF HUMAN STRUCTURES, AND JUST A TEENY LITTLE SPORE OF THE CLIMBING FERN COULD SEED IN THERE AND THEN GROW UP AN ENTIRE BUILDING, FOR EXAMPLE, OR ACROSS A BRIDGE. PERHAPS 50 YEARS IN THE ABSENCE OF HUMANS, YOU WOULD GET ENTIRE STRUCTURES COVERED BY VINES. OVER TIME, THEY'D BE PULLING BUILDINGS AND BRIDGES AND OTHER HUMAN STRUCTURES DOWN. >> IN A LIFE AFTER PEOPLE, THE INVADERS ARE ON THE MARCH. BUT THERE'S ONE VILLAGE ON EARTH ABANDONED 65 YEARS AGO... BECAUSE OF AN INVASION OF A DIFFERENT KIND. INTO A LIFE AFTER PEOPLE. NATURE CONTINUES TO INVADE MAN'S STRUCTURES, PULLING DOWN ROOFS AND PULLING APART WALLS. FOR PROOF, ONE NEED ONLY WALK THROUGH SOME OF THE ABANDONED PLACES OF THE EARTH, LIKE THE VILLAGE OF TYNEHAM, AN EERIE SITE HIDDEN IN THE HILLS OF SOUTHERN ENGLAND. PEOPLE HAD LIVED AND FARMED HERE FOR MORE THAN 5,000 YEARS. THEN CAME THE SECOND WORLD WAR. THE BRITISH GOVERNMENT TOOK OVER THE VALLEY AS A TRAINING GROUND FOR AMERICAN TROOPS PREPARING TO INVADE AND LIBERATE FRANCE ON D-DAY. IN THE MIDDLE OF DECEMBER 1943, THE 252 INHABITANTS OF TYNEHAM WERE GIVEN UNTIL CHRISTMAS TO LEAVE. >> THE FARMERS BASICALLY SOLD EVERYTHING, AND THEY LEFT. SO IT WAS ACTUALLY REALLY SAD. THE VERY, VERY LAST PERSON TO GO OUT WAS THE LADY OF THE MANOR, AND SHE PINNED A NOTICE ONTO THE CHURCH DOOR AS SHE LEFT. "WE HAVE GIVEN UP OUR HOMES WHERE MANY OF US HAVE LIVED FOR GENERATIONS TO HELP WIN THE WAR TO KEEP MEN FREE. WE WILL RETURN ONE DAY AND THANK YOU FOR TREATING THE VILLAGE KINDLY." IT WAS THOUGHT THAT PEOPLE WOULD BE ALLOWED BACK. BUT WITH THE ONSET OF THE COLD WAR IN THE LATE FORTIES AND FIFTIES, THE ARMIES DECIDED TO RETAIN THE LAND. >> NO ONE HAS LIVED IN TYNEHAM SINCE 1943, AND THE VILLAGE HAS BEEN INVADED BY THE NATURAL WORLD. STONE FARMHOUSES BUILT IN THE EARLY 19th CENTURY DEMONSTRATE HOW TIME AND THE SEASONS CAN DESTROY WHAT MAN HAS BUILT. >> THIS IS A TYPICAL ENGLISH FARMHOUSE THAT'S BEEN ABANDONED FOR ABOUT 6 DECADES OR SO, AND THE PROCESSES OF NEGLECT HAVE BEEN ALLOWED TO HAPPEN. YOU CAN SEE HERE HOW THE TIMBER LINTEL HAS BEEN ATTACKED BY WOODWORM, DRY ROT. IT'S SPLIT AT A CRITICAL POINT NEAR TO THE SUPPORT, AND ALREADY THE STONE ABOVE IS LEANING PRECARIOUSLY ON THE POINT OF COLLAPSE. WITHIN A FEW YEARS OR SO, THAT'LL HAVE COLLAPSED TO THE FLOOR. AND YOU CAN SEE FROM THE CONDITION OF THE LOOSE BRICKS AND STONES ON THE GROUND THAT THAT PROCESS HAS ALREADY TAKEN PLACE IN OTHER PARTS OF THE BUILDING. THE WALLS HAVE FALLEN IN AS THEY'VE LOST THEIR SUPPORT. IN ANOTHER FEW HUNDRED YEARS, THIS WILL JUST BE A MOUND OF BRICK AND STONE. >> TYNEHAM BEARS THE SCARS OF AN AGGRESSIVE INVADER. >> THE BUILDING BEHIND ME IS SEVERELY DAMAGED AS YOU CAN SEE. NOW, THIS IS NOT ROTTING WOOD OR HIGH WINDS, THE NORMAL AGENTS OF DECAY, CAUSING THIS. >> IT'S THE WORK OF A CREATURE THAT CAN CLAW THROUGH THREE FEET OF EARTH IN LESS THAN A MINUTE: THE EUROPEAN BADGER. >> WHAT THE BADGERS HAVE DONE IS BURROW UNDERNEATH THE VERY WALLS OF THE BUILDING TO SUCH AN EXTENT THAT THERE'S BEEN A SIGNIFICANT COLLAPSE IN A NUMBER OF PARTS OF THE BUILDING. >> BADGERS ARE AMONG THE WORLD'S FASTEST DIGGERS AND HAVE BEEN KNOWN TO CREATE TUNNEL SYSTEMS AS MUCH AS A THOUSAND FEET LONG. >> THIS GABLE WALL IS ABOUT 3 FEET THICK. THE ORIGINAL BUILDERS MUST'VE THOUGHT IT WOULD LAST FOREVER. AND IF THE BADGERS CONTINUE TO EXTEND THEIR PROPERTY, THEY WILL EVENTUALLY DESTROY THE PROPERTY ERECTED BY THE PREVIOUS OCCUPANTS, THE HUMANS. IT COULD LAST FOR ANOTHER 50 YEARS, 60 YEARS BEFORE THE BADGERS FINALLY CAUSE THE BUILDING TO COLLAPSE. >> CREATURES MUCH RARER THAN BADGERS ALSO CALL TYNEHAM HOME. IN THE ABSENCE OF MAN, AND MAN'S POISONS AND PESTICIDES, ANIMALS ARE THRIVING. >> IT HAS BECOME A SANCTUARY FOR MANY, MANY SPECIES OF BIRDS AND ANIMALS AND ALSO BUTTERFLIES. >> ONE ANIMAL ACTUALLY PROTECTS TYNEHAM FROM TOTAL CONQUEST. THE ARMY ALLOWS GRAZING SHEEP FROM NEARBY FARMS TO KEEP THE GRASS SHORT. WITHOUT THE SHEEP, THE VALLEY WOULD BEGIN TO RETURN TO ITS ANCIENT CONDITION. >> NATURE WOULD TAKE OVER. ALL THE SHORT GRASS WOULD REVERT TO VERY COARSE GRASSES. THAT WOULD BE SUCCEEDED BY GORSE, BRAMBLE, SCRUB, AND THAT EVENTUALLY WOULD BE SUCCEEDED BY TREES. SO WE WOULD BECOME A WOODLAND, AND MUCH OF BRITAIN, OF COURSE, A THOUSAND YEARS AGO, WAS WOODLAND. >> THE TIMBER POSTS WILL ROT AND FALL. THE BARBED WIRE WILL TAKE HUNDREDS OF YEARS TO CORRODE, BUT EVENTUALLY THE IRON AND CARBON WILL BE REABSORBED INTO THE EARTH FROM WHICH THEY CAME. IN SEVERAL THOUSAND YEARS, GEOLOGICAL PROCESSES WILL COMPLETE THE INVASION OF TYNEHAM. >> EVENTUALLY, SOIL WILL BE BLOWN IN, AND TREES WILL TAKE ROOT, AND THE ONLY EVIDENCE OF A FORMER COMMUNITY WOULD BE CAPABLE OF BEING GAINED BY EXCAVATING DOWN TO FIND THE REMNANTS OF THESE STONE BUILDINGS, BUT, OTHERWISE, IT WILL LOOK LIKE NATIVE COUNTRYSIDE. INTO A LIFE AFTER PEOPLE. THESE ARE THE LAST DAYS OF SHANGHAI'S ORIENTAL PEARL TOWER. IN THE TIME OF HUMANS, IT WAS A MAJOR PART OF THE SKYLINE OF CHINA'S BIGGEST CITY, A SKYLINE THAT HAS SUNK 35 INCHES UNDER ITS OWN WEIGHT SINCE MAN DISAPPEARED. NOW THE WATERS OF THE HUANGPU RIVER HAVE FLOODED THE STREETS, AND EVEN THOUGH THE PEARL'S THREE CONCRETE-AND-COMPOSITE SUPPORT COLUMNS ARE THRUST MORE THAN 100 FEET INTO THE GROUND, THAT FOUNDATION IS ROTTING AWAY. THE COLUMNS LEAN ONE WAY, THE SPIRE ANOTHER. UNDER THE UNBEARABLE STRAIN, THE FORMER PRIDE OF SHANGHAI CRACKS AND FALLS. 100 YEARS AFTER PEOPLE. THE SEVEN-MILE BRIDGE ONCE CONNECTED MIAMI AND THE FLORIDA KEYS. BUT A HUNDRED YEARS OF STORMS AND HURRICANES HAVE WEAKENED SOME OF THE 440 CONCRETE SECTIONS... SENDING PARTS FALLING INTO THE OCEAN, UNTIL THE SPAN LOOKS LIKE A ROW OF BROKEN TEETH. IN PHOENIX, THE 90-SQUARE-BLOCK BUSINESS DISTRICT, ONCE THE FINANCIAL CENTER OF ARIZONA, IS A CHAOS OF MUD AND DEBRIS. >> THINK ABOUT THE DUST THAT COMES THROUGH WITH OUR SANDSTORMS, AND THEN THE RAIN THAT COMES THROUGH TO FORM MUD THAT WOULD BUILD YEAR AFTER YEAR. THEN THIS PLACE WOULD CERTAINLY LOOK A LOT DIFFERENT THAN IT DOES TODAY. >> MUD-FILLED FLOORS CRASH AND TUMBLE, AND THE PILED-UP DEBRIS COLLAPSES THE TOWERS FROM WITHIN. THEIR SHATTERED GLASS WILL BE TAKEN UP BY THE NEXT GREAT SANDSTORM AND SLICE THROUGH OTHER STRUCTURES... UNTIL PHOENIX IS DESOLATE. WHILE SOME OF MAN'S STRUCTURES FALL FROM ABOVE, OTHERS ARE LITERALLY EATEN FROM BELOW. IN THE TIME OF HUMANS, MORE THAN 1,000 MILES OF MAN-MADE EARTHEN BARRIERS CONTROLLED FLOODING IN THE EVERGLADES. BUT THOUSANDS OF SAILFIN CATFISH, DESCENDANTS OF PETS BROUGHT FROM SOUTH AMERICA IN THE 1970s, HAVE INVADED THE DIKES AND LEVEES, DIGGING 3-FOOT-DEEP BURROWS TO LAY THEIR EGGS. >> SO YOU HAVE A DIKE, AND YOU HAVE THE CATFISH DOWN HERE. THIS IS THIS YEAR, THAT'S THE NEXT YEAR, THAT'S THE NEXT YEAR, AND EVENTUALLY OBVIOUSLY THE DIKE COULD FAIL. >> AS THE BARRIERS BREAK, DRY AREAS BECOME SWAMPLAND. EVEN AN OUTPOST AS SEEMINGLY PERMANENT AS THE KENNEDY SPACE CENTER TEETERS ON THE EDGE OF A MARSHY SWAMP. IN THE TIME OF HUMANS, ALLIGATORS WERE ALWAYS AT ITS GATES, AND LAUNCHPADS FROM THE DAWN OF THE ERA OF SPACE EXPLORATION ALREADY LAY ABANDONED AND RUSTING. NOW THE REMAINING STRUCTURES AND ROCKETS ARE VICTIMIZED BY REPEATED SOUTH FLORIDA HURRICANES, AND THE ONLY CREATURES WAITING TO LAUNCH FROM HERE... ARE HUNGRY VULTURES. 196 MILES DOWN THE COAST, MIAMI HAS RUN OUT OF BEACH. IT'S A REVERSAL OF FORTUNE FOR A PLACE THAT GOT ITS START AROUND 1914, WHEN DEVELOPERS BEGAN FILLING IN OVER 2,500 ACRES OF MANGROVE SWAMP AROUND A NARROW COASTAL SANDBAR TO CREATE A HIGH-END BEACH RESORT. THE CREATION OF MIAMI BEACH CONTAINED THE SEEDS OF ITS DESTRUCTION. >> AS COASTAL STRUCTURES ARE CONSTRUCTED, IT INTERRUPTS THE NATURAL FLOW OF SAND ALONG THE COASTLINE OF SOUTH FLORIDA, AND IT PRODUCES A DEFICIT OF SAND, AND THAT REQUIRES EXTENSIVE REPLENISHMENT. >> BY THE LATE 20th CENTURY, SO MUCH OF THE COAST HAD BEEN EATEN AWAY THAT SOME HOTELS LOST 80% OF THEIR BEACHFRONT. STARTING IN THE 1970s, ENGINEERS TRUCKED IN MILLIONS OF TONS OF NEW SAND IN A BATTLE AGAINST TIME AND THE ATLANTIC. NOW, A CENTURY AFTER PEOPLE, THE INVADING OCEAN IS UNOPPOSED AS IT REACHES UNDER THE FOUNDATIONS OF ONCE-LUXURIOUS HOTELS. >> YOU EXPECT AFTER 100 YEARS OR LONGER, THOSE BUILDINGS WOULD START COLLAPSE. >> THE FORMER VACATION PALACES FALL INTO EACH OTHER AND TOPPLE AT LAST INTO THE WAITING GRASP OF THE ATLANTIC. >> 150 YEARS AFTER PEOPLE. BURMESE PYTHONS DOMINATE THE EVERGLADES, AND THEY HAVE INVADED FRESH TERRITORIES. CAPABLE OF LIVING IN MORE VARIED CLIMATES THAN ALLIGATORS, EVEN ABLE TO CLIMB TREES, THE PYTHONS NOW DOMINATE THE LOWER 40% OF WHAT WAS ONCE THE UNITED STATES. 200 YEARS AFTER PEOPLE. CITIES LIKE PHOENIX BARELY EXIST. ELSEWHERE IN ARIZONA, SOME DESERT STRUCTURES STILL STAND, BUT NOT FOR LONG. THE "SKYWALK," UNVEILED IN 2007, IS A 4-INCH-THICK, 70-FOOT-LONG GLASS PLATE SET 4,000 FEET ABOVE THE GRAND CANYON, ANCHORED WITH 500 TONS OF STEEL BEAMS 2 1/2 INCHES THICK. WORKERS USED TO CHECK IT EVERY DAY FOR CRACKS AND FLAWS. BUT IN A LIFE AFTER PEOPLE, 200 YEARS OF CORROSION HAVE ROTTED AWAY THE STEEL SUPPORTS. >> THIS BRIDGE IS BEAUTIFULLY BUILT, BUT ONE WOULD EXPECT THAT WITHOUT CONSTANT MAINTENANCE, IT WOULD COME APART FROM ITS MOORINGS. >> IT TAKES THE SKYWALK ONLY 15 SECONDS TO FREEFALL TO THE CANYON FLOOR. IN MIAMI, THE SKYLINE IS GONE. ONLY A FEW RUSTED GIRDERS STILL POINT SKYWARD. NOW LIVING IN FLORIDA'S SUB-TROPICAL JUNGLE, THESE CHIMPANZEES ARE THE DESCENDENTS OF THOSE THAT FOR 20 GENERATIONS OCCUPIED ONE OF THE CITY'S MAN-MADE TOWERS, WHERE THEY LEARNED HOW TO FARM EGGS, EATING WHAT THEY NEEDED AND ALLOWING THE REST TO HATCH, THEREFORE PRODUCING MORE BIRDS AND MORE EGGS. IT WAS ONCE THOUGHT THAT HUMANS WERE THE ONLY SPECIES THAT COULD PASS ON LEARNED BEHAVIORS AND TRADITIONS TO SUBSEQUENT GENERATIONS. BUT RESEARCH IN THE LATE 20th AND EARLY 21st CENTURIES SHOWED THAT CHIMPANZEES SHARE THIS ABILITY. THIS SETS THE STAGE FOR THE POSSIBILITY OF THESE CHIMPS TO BEGIN TO CREATE A CIVILIZATION OF THEIR OWN. >> ONE COULD ENVISION A SCENARIO IN WHICH CHIMPS, WHO RAN OUT OF THESE BUILDINGS, STARTED BUILDING THEIR OWN TOWERS AS A WAY TO PROTECT AND FARM THE BIRDS, BUILDING PLATFORMS HIGH IN TREES TO ATTRACT THE BIRDS. YOU'D HAVE THE BEGINNINGS OF CONSTRUCTION IN A NEW SPECIES. IF THEY USED WHAT WAS LEFT OF OUR CULTURE-- OUR BUILDINGS, OUR ROADS, OUR BRIDGES-- TO DEVELOP A TRICK THAT GAVE JUST ONE SMART TRIBE A LEG UP TOWARD A SOMEWHAT CIVILIZED WAY OF LIFE, IT COULD BE OUR LAST GIFT, OUR SORT OF PAYBACK. >> WHETHER OR NOT THIS CHIMPANZEE TRIBE COMPLETES THE MULTIMILLION-YEAR EVOLUTIONARY JOURNEY THAT LED TO THE FIRST HUMAN BEINGS, THE USE OF TOOLS AND DOMESTICATED ANIMALS COULD MAKE THESE APES THE DOMINANT LIFE FORMS IN FLORIDA'S FUTURE. LONG AFTER SKYSCRAPERS IN CITIES LIKE SHANGHAI HAVE CRUMBLED, OTHER SITES REMAIN. ALTHOUGH IT APPEARS ETERNAL, TIME IS RUNNING OUT FOR THE TAJ MAHAL. THIS WORLD-FAMOUS STRUCTURE IN AGRA, INDIA, WAS BUILT IN THE 17th CENTURY BY EMPEROR SHAH JAHAN IN MEMORY OF HIS WIFE. ALTHOUGH IT HAS MARBLE WALLS 15 FEET THICK IN PLACES, IT STANDS ON CLAY ABOVE PART OF INDIA'S MOST DANGEROUS SEISMIC ZONE. AS A GIANT QUAKE LIQUEFIES THE CLAY SOIL, THE MINARETS FALL AWAY, AND THE STONE AND MARBLE COLLAPSE. 2,000 YEARS AFTER PEOPLE. THE DESERT THAT HAS BURIED PHOENIX HAS ITSELF BEEN TRANSFORMED. 2,000 YEARS OF RAIN AND SNOW HAVE RECHARGED THE WATER TABLE, BRINGING THE UNDERGROUND AQUIFER TO THE SURFACE AND FEEDING THE RIVERS AGAIN. WITH NO HUMANS USING THE WATER, PHOENIX IS A VAST SAVANNAH, AS IT WAS AFTER THE LAST ICE AGE. >> IT WOULD BE A BEAUTIFUL, LUSH PARADISE OF WILD CREATURES. THEY WILL RETURN AND THRIVE IN THE DESERT. >> BEASTS THAT WOULD HAVE AVOIDED PEOPLE HUNT AS THOUGH THEY NEVER EXISTED. THE ANIMALS HAVE FORGOTTEN MAN... OR HAVE THEY? >> WOULD ANYBODY TALK ABOUT US AFTER WE'RE GONE? >> IN THE WATERS OFF FLORIDA, THE DESCENDANTS OF DOLPHINS THAT ONCE SHARED THESE WATERS WITH HUMANS NOW FROLIC. IS IT POSSIBLE THAT THEY HAVE LEGENDS AND STORIES OF THE TIMES WHEN STRANGE MAMMALS SWAM WITH THEIR ANCESTORS? >> DOLPHINS CERTAINLY COMMUNICATE USING SOUND. IF THEY TELL STORIES ABOUT US, IT'S MORE IN THE SENSE OF SONAR IMAGES, AN IMPRESSION THAT THESE PEOPLE ON LAND USED TO GIVE A MEAL OUT OF FISH. I IMAGINE THAT WE WOULD FILL THE NICHE THAT IN A LOT OF OUR TALES ARE FILLED BY THE GODS: THE LEGENDARY CREATURES WHO COULD BRIDGE THE CHASMS. IT'S AN INTERESTING NOTION. >> WHILE DOLPHINS WERE NATIVE TO THESE WATERS, MANY OF THE CREATURES THAT THRIVE IN THE ABSENCE OF HUMANS WILL BE INVADERS FROM OTHER LANDS. >> SO WHILE BUILDINGS AND INFRASTRUCTURE MIGHT DEGRADE OVER TIME, OR THE FOOTPRINT OF HUMANITY MAY DISAPPEAR, I BELIEVE THE INTRODUCTION OF EXOTIC SPECIES IS FOREVER, AND IT WILL PERMANENTLY CHANGE THE LANDSCAPE. I BELIEVE THIS IS MAN'S LEGACY. >> OLD HABITATS HAVE NEW RULERS. FAMILIAR LANDSCAPES HAVE BEEN TRANSFORMED. MAN'S WORKS HAVE FALLEN. WHEN THE INVASIONS ARE COMPLETE, THERE WILL BE NO THANKS FROM THE VICTORS OR BLAME FROM THE DEFEATED. EVERY SPECIES THAT REMAINS WILL KEEP FIGHTING FOR TURF, FOR SURVIVAL, FOR LIFE AFTER PEOPLE. IN THE NEXT EPISODE OF<i> LIFE AFTER PEOPLE...</i> THE WORLD'S MOST FAMOUS WORK OF ART FALLS VICTIM TO A PREDATOR THE SIZE OF A DROP OF PAINT, SHRINES TO LIBERTY CRACK AND CRUMBLE, AND TWIN TOWERS FALL... AS WE LEARN THE FINAL FATE OF ALL THAT HAS BEEN
