"Planet Earth: a place of constant change at the hands of powerful beings:" "us." "Hundreds of thousands of miles into space and deep beneath the earth's surface we've created an amazing world, shaping continents, creating ingenious monuments and transforming landscapes." "But the only way to fully understand the scale of our influence is to witness the world without it." "If we suddenly disappeared, what would happen to our highways, cities," "rivers, our greatest monuments?" "Enter a desolate world;" "a world without humans." "One minute from now, every single person on earth will disappear." "It doesn't matter how or that it's far fetched." "What's important is what will happen when we're gone." "Of the billions of people in the world, half live in cities." "Farms and pastures cover a third of all dry land." "We've dammed and diverted half the world's major rivers." "500 million cars clog the roads and highways." "We've affected the air, the sea" "and the land." "But have we changed the earth forever?" "If we vanished, could the planet recover, even erase all evidence that we ever existed?" "Friday, June 13th." "In Berlin, it's 1:30 in the afternoon." "Across the Atlantic, stockbrokers get an early start on Wall Street." "Las Vegas is anything but sleeping, and in Tokyo, parents tuck their kids into bed." "Then suddenly, the human race comes to an end." "Every single person in every corner of the world vanishes." "Cities transform into ghost towns." "Laughter lingers only to become a quickly fading echo." "Things come to a shocking halt." "The moment we disappear, the world starts to change." "There's an eerie silence in cities that are suddenly, a little cooler." "The average human body puts out as much heat as a 100-watt light bulb." "Take away eight million people from New York, and the entire city cools down by a fraction of a degree." "Even though we're gone, the machines we left behind keep working." "All over the world, hundreds of planes approach airport runways." "Most descend at over 100 miles an hour, and today, all with empty cockpits, every landing will end in a fireball." "Thousands of other planes fly through the sky on autopilot." "Many will stay in the air for a few more hours, but when the fuel runs out, gravity will pull them back to earth." "In a world without humans, cities continue to function on thousands of automated systems." "Computers keep in touch with hundreds of satellites, which will continue to transmit information across the globe, as long as the power stays on." "Power is generated by more than 50,000 power plants around the world." "In the US, coal-fired plants produce half of the country's electricity." "To keep the fires burning, they require a steady supply of coal." "But there will never be another delivery." "The coal plants start to fail." "The Western grid is knocked out by a rolling blackout." "The shimmering lights of Las Vegas will never shine again." "The sun breaks through the clouds in Pennsylvania, which still has power." "As temperatures rise, automatic air conditioners turn on." "The need for electricity surges." "This area relies on wind power in addition to coal." "Even without us, the wind turbines are still running, so there's enough power to meet the new demand." "But at the local power station, there's no one to decide that more power is need." "Computers detect a problem and shut down the entire system." "Pennsylvania is now without power." "Niagara Falls, Canada is home to one of the world's first commercial hydroelectric plants." "It provides power to more than 2 million homes." "A mile upstream, water surges into tunnels that snake under the city." "When it reaches the power plants, it drives the turbines and creates electricity." "Less than two hours ago, people were monitoring this powerful system." "But with no one at the controls, the turbines flood and the plant shuts itself down." "Seconds later, blackouts sweep through parts of Ontario and New York." "The world-wide loss of electricity reaches the nuclear power plants." "Automated systems detect that the electrical grid is failing and they shut off the reactors." "But this is just the beginning." "Six hours after humans disappear the sun goes down in Europe." "The last power plants go offline." "The dark ages are back." "The sun is still shining on North America and thousands of cars are still running." "Every gallon of gas they burn sends 19 pounds of carbon dioxide into the air." "This greenhouse gas can pollute the sky for the next one hundred years." "Without us, another source of man-made global warming is also disappearing." "Planes send out water vapor in their exhaust and the cold air transforms the vapor into clouds." "But as the last planes fall from the sky, these man-made clouds disappear with them." "Fuel-starved jets aren't the only disasters rolling through this new world." "All over the globe, industrial plants react to the permanent loss of power." "Some gases need electricity to keep them cold enough to be stored in liquid form." "If they don't have power, the cooling units stop working." "Eventually, the liquids come to a boil and create dangerously high pressures." "Many tanks have relief valves that vent gas to avoid explosions." "But hundreds of thousands of tanks all venting at the same time is unimaginable." "The gases spread wherever the wind blows, and some are heavier than air, a danger to any creature that roots around in the soil." "The same chemicals that made the modern world possible are now set loose to destroy it." "Emergency back-up systems are sustaing the world's nuclear power plants." "Automatic diesel generators have kicked in to prevent a catastrophic meltdown." "But the diesel fuel won't last forever." "All over the world, pets are getting hungry." "If they don't find food and water soon, they'll die." "But they're not the only animals affected." "The global power failure is also impacting zoos and safari parks." "No longer contained by electric fences, predators are free to explore their new world and its dangers." "Chlorine gas from a derailed train killed this herd of deer." "Changes are also taking place at some natural gas facilities." "With the power off, the liquid natural gas is starting to vent." "But most of it's being burned off, an automatic safety feature designed to contain gas leaks at plants." "With the tanks venting, the explosive gas can reach idling cars, left behind when their owners disappeared." "It only takes one small spark, and the new world echoes with explosions." "And this is just the start." "Fires like this will burn for days as hundreds of chemical plants around the world send dangerous toxins into the air." "In just six short hours, our disappearance has triggered a series of catastrophes around the world." "And as animals and atoms infiltrate this world without humans, a much bigger disaster could be looming." "It's been three days since humans disappeared from the Earth." "Power plants have failed." "Machines have ground to a halt." "Thousands of tons of toxic chemicals have escaped from the world's plants." "In London, England, Big Ben is due for its winding." "But without the help of a human hand, it rings for the last time." "Human time and human history have stopped." "But life on Earth continues." "Houses and apartments are still inhabited by increasingly hungry pets." "It's been three days since anyone has fed them, so they devour anything they can find." "In the US, tens of millions of dogs were trapped when their owners vanished." "Now, they either have to break out of their homes or die." "With the failure of power plants around the globe, pets inherit a dark world." "At nuclear power plants emergency diesel generators started working as soon as the electricity failed." "But without power, this building, and hundreds like it, will soon cause an unprecedented disaster." "This is the spent fuel handling building, where radioactive fuel is stored in cooling pools after it's used to generate power." "The pool is 30 feet deep and filled with 400 tons of spent nuclear fuel, the result of atoms splitting to create nuclear energy." "And split atoms keep releasing heat and radiation." "The spent fuel is contained in zircaloy tubes." "And they're dangerous." "If they're not kept under water, they'll quickly heat up to 1000 degrees." "They need to be kept in flowing, refrigerated water for years before they cool off." "Nuclear storage sites can be found all over the world." "There are 75 in the US alone." "The spent fuel is safe as long as the generators stay on and keep the water cool." "But if someone doesn't refill them, they'll grind to a stop." "And this time, no one's coming." "Pets are now learning to live off the land." "For some, life was once rich with food, water." "But now, scrounging through garbage is what provides meals." "As for water, things have changed down by the river." "Pumps at the sewage treatment plants don't work without electricity, so raw human sewage is seeping into lakes and rivers." "Abandoned pets aren't the only animals struggling to survive." "The world is filled with cattle," "1.4 billion of them, and without humans, they too have been forced to fend for themselves." "Now that we're gone, 90,000 cows a day are saved from slaughter in the US." "But dairy cows need 100 pounds of food and 25 gallons of water every day to survive." "With no electricity, their water supply is drying up." "The cows are on their own." "In a cruel twist of fate, they're safe from the slaughterhouse, but they may all die from dehydration." "And things don't look much better for zoo animals." "Trapped in their cages, many of them will die." "But those once contained by electric fences are prisoners no more." "They finally break free." "Elephants need up to 400 pounds of food a day, and finding it in the suburbs will be a struggle." "These enormous herbivores will give a serious pruning to each neighborhood they visit." "Predators also prowl the suburbs." "These hungry lions have spotted another escapee from the zoo." "But lions are skilled hunters on savannahs, not in public parks." "And climbing plastic is one challenge they can't win." "With the baboon out of reach, they need to find some easier prey." "Camels, on the other hand, are having no problem finding food." "They eat almost any vegetation, grass, leaves, even thorns that other animals avoid are on the menu." "And with food at every turn, camels easily adapt to a world without humans." "The lions have moved from the park to the porch as they continue their search for food." "On both sides of the glass, an unexpected and unusual sight." "Overhead, birds are migrating." "And without humans around, many more will survive this year." "At night, birds use the stars to navigate." "With the power on, lights and glowing skyscrapers resemble stars, so birds often circle them al night and die of exhaustion." "But in a world without humans, there is no power, so migrating birds fly more safely through major cities." "Millions will reach their destinations." "Their population will boom." "On city streets, dogs have gone from pets to predators." "Within a week of losing their human masters, they're forming packs and fighting for dominance." "Which hasn't happened since 2005, when Hurricane Katrina forced humans to evacuate New Orleans and leave many dogs behind." "The dogs started hunting in packs and threatening humans." "But not all dogs are equal." "With more than 400 different breeds, some varieties, like this poodle, don't have the size or strength to compete." "And like wolves, dogs will kill their own, so every small dog is a potential meal." "In the next few weeks, most smaller dogs will be killed." "At nuclear power plants, diesel generators are finally running out of fuel." "The power goes off for good inside the spent fuel buildings." "The cool water stops flowing." "The temperature starts to rise." "In just a few days, the water will boil and evaporate." "And without people to stop it, a nuclear disaster greater than the world has ever seen is now inevitable." "A massive dose of radiation, 500 times greater than what was unleashed on Hiroshima, will be released." "Dogs from the city are roaming the countryside looking for food." "And they're hungry enough to try just about anything, even corpses." "The fields are littered with dead dairy cows." "When we were around, dairy cows provided us with milk for 8000 years." "Now, their rotting carcasses will do nothing more than sustain hungry dogs, who just two weeks ago were probably eating comfortably from a can." "Not all cows are dead." "In the wide-open spaces of western North America, free-range cattle are thriving." "But the same can't be said for the domesticated animals trapped in pens." "1.5 billion chickens have died in the US, leaving only free-range poultry to roam among a world full of predators." "Death is in the air." "A time bomb ticks." "This world without humans is about to suffer devastating blows." "Ten days after humans disappear from the Earth, the power is off." "Cities are quiet." "Animals that escaped from zoos and safari parks roam free but fight to survive." "Predators are a problem, but we left behind other deadly forces." "For days, super-heated steam has been escaping from the spent fuel building of this nuclear power plant." "With no emergency power, there's nothing to keep the fuel from heating up." "The fuel burns through casings and sets fire to everything in the room." "Radiation equal to 500 atomic bombs is about to explode." "This is a nuclear disaster and there's no one to stop it." "A deadly mix of radioactive particles spews from the plant." "Some of them, like strontium 90, will be dangerous for 300 years." "Plutonium will be radioactive for 240 thousand years." "Pine trees near the nuclear power plant are first to die." "Radioactive particles cling to their bark and resin." "Chlorophyll, which makes the trees green, is damaged, and as a result, they turn red." "The last time a forest died like this was during the Chernobyl disaster in 1986." "Radiation contaminated an area of 50,000 square miles, the size of Alabama." "In a world without humans, this scene is repeated again and again." "Nuclear power poisons the earth we left behind." "There are 6 nuclear power plants in Illinois." "Radioactive smoke fills the streets of Chicago, the site of the world's first self-sustaining nuclear reaction." "Fires break out at many of the 30 nuclear plants located in the eastern US." "Each one is almost 20 times more radioactive than the Chernobyl disaster." "Many of Europe's 173 reactors also ignite." "Their spent fuel burns." "Carried by the wind, the radiation is an invisible poison that settles over thousands of square miles." "If we were still on the planet, it would cause cancer in millions of people." "Giant plumes of radioactive smoke and particles spread across the northern hemisphere." "Winds push radiation away from the reactors in Europe." "If conditions are right, it could reach as far as North Africa." "Radiation from some of Japan's 53 reactors drifts across the Pacific Ocean." "The world's most remote islands are in its path." "Rain washes much of the radiation from the sky, concentrating its deadly effects." "Some areas become more deadly than others." "Large animals flee areas where plants have died from radiation poisoning." "But small creatures aren't as lucky." "Many live on the forest floor where leaves and soil are coated in radioactive particles." "Radioactive beta particles can only penetrate half an inch into living tissue." "For large animals like deer, their vital organs are spared a direct assault." "But it's different for small animals." "Their organs aren't so insulated." "Radiation cripples them." "In the worst hit areas, over half of the rodents and insects die." "For animals in the cities and suburbs, they have access to food that's much less radioactive." "Grocery stores can provide enough food for city mice to last for generations." "They also make a perfect breeding ground." "A female mouse can give birth to more than 70 offspring in a year." "Since radiation has killed many of the mice outside, this cat heads indoors, where he just might get the 8 mice a day he needs to stay healthy." "Humans need a variety of foods to get all the fat, protein and vitamins we require." "Cats don't." "They can produce their own vitamin C, and they can get the rest by eating the organs and entrails of mice." "All over the planet, animals are invading the human world to find food." "And what we left behind will keep them alive, even as clouds of radiation spread." "Radiation has dissipated." "Cities are quiet and the atmosphere is improving." "The air is clearer." "In Manhattan and Toronto, the view has increased from 20 miles to 100." "City dogs still roam the countryside looking for food." "Most of these former pets are far from skilled hunters." "But if they're hungry enough, they'll try to attack anything once." "Like wolves, dogs hunt by instinct, going for the legs or neck to bring down a large animal." "But instinct is no match for a beast weighing thousands of pounds." "The dogs aren't a threat." "And without humans, the elephants are predator-free." "In just a few months, pets and zoo animals have become killers in a radioactive world." "But another challenge is on the horizon:" "winter." "Six months after humans disappear." "It's early December." "In a world without us, former zoo animals and pets either adapted or died." "In some parts of the world, animals are about to face their next challenge:" "the coming winter." "A common misconception is that cockroaches can survive almost anything." "But cockroaches are imports from the tropics and only spread north as we started to use central heating." "With the electricity gone, and the furnaces off, millions of cockroaches will be dead by the new year." "For other animals, our sudden disappearance isn't a problem, it's an opportunity." "Raccoons and squirrels already know that the best way to survive the cold is to sleep through it." "And this winter, they have many new dens to choose from, that are drier and safer than sleeping outside." "These squirrels are tree dwellers, so they camp upstairs." "Skunks, on the other hand, prefer the ground." "Hibernating animals don't need heat, even when their body temperatures drop almost to the freezing point." "It's a survival strategy their ancestors evolved long ago." "But this African elephant isn't equipped to deal with frigid temperatures." "His body evolved to get rid of heat, not keep it." "In Africa, his thin ears would have helped him keep cool." "But now, they're just getting frostbitten." "To survive, he needs to head south." "After winter comes a spring like never before." "In the forests near ruined nuclear power plants, it's a silent season." "Poisoned by radiation, these evergreens have lost their ability to grow new shoots and branches." "But further from the power plants, spring helps repair the damage we left behind." "Rain washes radioactive debris from leaves and bark." "Poisonous atoms are driven underground." "They're still a threat to anything that lives there, but our radioactive fingerprint is starting to disappear." "And that's not the only threat to animals that has vanished." "Without humans there is no one to hunt." "And a population explosion of animals takes over the empty spaces." "This new world is filled with new opportunities." "It's almost been a year since every car on Earth ran out of gas." "In their last year on the road, cars pumped 7 billion tons of carbon dioxide into the air, more than one ton for every person on Earth." "This greenhouse gas accounted for half of the impact humans had on global warming." "But now, the carbon dioxide will be cleaned up faster than ever before." "In spring, new plants and leaves need carbon to grow." "They draw it out of the air, naturally cleansing a polluted planet." "New trees soak up more carbon than old ones." "This spring, nature has many new places to grow." "For the past ten thousand years, we've been imposing our will on the planet." "In downtown Los Angeles, two thirds of the land is covered in roads and parking lots." "We made our mark in the suburbs, too." "In the US, lawns and golf courses cover an area bigger than Florida." "Now that we're gone, nature is reclaiming the Earth." "Nothing is immune." "Millions of miles of roads and highways are slowly being invaded by moss and lichen and all they usually need is water." "Cracked roads are filled in with moss and grass." "A once carefully groomed soccer field now grows wild." "Fast-growing trees take root where children once played." "All these new plants allow nature to soak up greenhouse gases like carbon dioxide faster than when humans were here." "Year after year, our grip on the land is loosening." "It's been thirty years since humans disappeared." "At night, the only light comes from the moon and the stars." "Once, Earth was so well lit it was easily seen from space." "But thirty years after the lights went out," "Earth's inhabitants watch a new kind of light show." "Hundreds of strange shooting stars fly through the sky." "A few even make it to the ground." "The fiery wreckage contains clues that these are not normal meteorites." "These shooting stars are some of the last survivors of the space age." "Humans left 25,000 objects orbiting the Earth." "Most of it was junk, clamps, pieces of rockets, remnants left from our 50 years of working in space." "And without us there's nothing to keep it from falling back where it came from." "When solar storms erupt on the surface of the sun, radiation expands the Earth's atmosphere and slows orbiting satellites and space junk." "Gravity does the rest." "Satellites in higher orbits have been slowly spiraling closer to the Earth for the last 30 years." "Now, with dead batteries, they plummet to the ground." "Back on Earth, the world continues to change." "Human homes slowly collapse." "Plants and animals help speed up the process." "For three decades animals have gnawed through roofs and walls." "Dirt and seeds have blown into houses." "Living rooms have become homes for trees." "Rain falls into dining rooms and kitchens." "Ceilings and floors rot and fall apart." "Schools once taught about human triumphs over nature." "But in just thirty years, nature reclaims much of what humans took away." "Changes are especially obvious along the world's coastlines, where we built many of our cities and homes." "Now, hurricanes wash them away as if they never existed." "From Miami to Halifax, mansions and cottages are destroyed." "Man-made global warming still affects the world's oceans, even 30 years after people stopped polluting them." "While houses collapse on land, remnants of the human world create new homes for marine life." "At least 50,000 ships are strewn along seashores or rusting on the sea bottom." "These shipwrecks are a magnet for sharks and fish, and they provide thousands of places for fish to live and breed." "Above the waves, nature's advance continues." "Humans used one third of all dry land for farms and pastures." "But now, fields originally planted with single crops have been invaded by a variety of fast-growing weeds and wildflowers." "Every year, forests expand their territory, growing closer to meadows of bushes and shrubs." "It took us 10,000 years to force our will on the planet." "Carve our mark on every continent." "Now, nature is invading civilization's citadel:" "the concrete jungle." "Welcome to a world thirty years after humans disappear." "There is no power." "The screech of cars and jets will never be heard again." "But cities are still filled with life." "Wild dogs hunt in packs, roaming the roads and sidewalks we once roamed." "Plants and trees are taking over." "New York's Central Park is actually getting bigger." "Dirt and seeds blow through the city and take root everywhere." "Manhattan turns from grey to green." "Times Square once was a hot spot for millions to celebrate the start of a new year, now, it's being engulfed by a blanket of green." "Nature is reclaiming the world, city by city." "In London, young trees sprout in Trafalgar Square." "In Berlin, a forest surrounds the Brandenburg gate, once the division of East and West Germany." "Thirty years after we disappear, glass tumbles onto deserted streets." "Once, glass-covered office towers symbolized the modern age." "There was more glass in one skyscraper than all of the glass made during the Roman Empire." "But most skyscrapers were built using caulk and metal clips to keep the windows in place." "After thirty years, the clips are rusting." "The caulking cracks." "Water gets into the cracks and the frames get weak." "The era of the gleaming skyscraper is ending." "High above them, hawks and other raptors are on patrol, keeping an eye out for scampering prey." "The concrete jungle is born." "Relics of human existence slowly disintegrate." "After years of neglect, paint peels away." "Raw metal is exposed to the elements, rust spreads." "The steady advance of nature also damages concrete." "This was once a train station crowded with commuters." "Now its concrete roof is falling apart." "Concrete is strong, but extremely porous." "Rain washes away the limestone used to make it." "Stalactites grow a centimeter every year and then break off, slowly weakening the concrete." "This roof will collapse in less than 20 years." "Humans may be gone, but we're still contributing to this destruction." "We burned fossil fuels and pumped tons of carbon dioxide into the air for more than a hundred years." "Now, the planet is slowly getting rid of our pollution." "As carbon dioxide returns to earth, it mixes with rainwater and produces carbonic acid," "which eats away at the world's concrete." "Much of our modern world rose from concrete." "Now, these soaring buildings, engineering marvels, are ready to fall." "Cities all over the world face the same fate:" "a slow disintegration." "Without windows, high-rise offices are now occupied by birds and animals." "Exposed to the elements, ceiling tiles and drywal are no match for more than half a century of wind and rain." "Rust is everywhere." "Moisture has penetrated the walls and doors, and paint peels off every surface." "But the damage goes deeper than that." "A city like Paris gets up to 25 inches of rain every year." "Now that the windows are gone, nothing can stop the rain from flooding the concrete skeleton of this office tower and creating cracks." "The cracks are caused when carbon dioxide penetrates the maze of microscopic pores in concrete." "Then, it winds in until it reaches the rebar, metal that gives reinforced concrete its strength." "Rebar is usually hidden from the outside world, but now, the carbon dioxide is causing the bars to rust." "As the rust radiates out from the steel, it expands, splitting and cracking the concrete." "The building is under attack from the inside out." "Cracks are appearing all over the world, and there's no one around to fix them." "When people were on the planet, problems like this would be repaired." "But now, cracked concrete can't be reinforced or replaced." "The damage runs unchecked." "And the changing seasons only makes matters worse." "As water turns to ice it expands and puts more pressure on the crumbling buildings." "The constant freezing and thawing makes the cracks grow." "In just one hundred years, the concrete becomes too fractured and brittle to support its load." "The upper floors collapse and their combined weight crushes the floors below." "The building crumbles to the ground." "Our cities are disintegrating." "The planet is absorbing what we left behind." "120 years after humans disappear, many modern skyscrapers have collapsed into heaps of rubble." "Concrete walls have been destroyed by a steady onslaught of air and rain." "But the new landscape has made cities a little cooler." "When we ruled the planet, heat from the sun was soaked up by black roofs and roads." "Asphalt absorbed 95 percent of the sun's light." "Black surfaces made cities up to 10 degrees hotter than surrounding areas." "But now that we're gone, asphalt is being covered by grasses and trees." "Shade keeps the ground cool." "The temperature drops." "The world's climate is changing." "Manmade global warming is finally coming to an end, thanks to oceans." "For the past 120 years, churning waves have absorbed carbon dioxide into the top layers of the seas." "Then, microscopic plankton and shellfish absorbed it into their bodies." "Many died and sunk to the bottom of the ocean, taking our carbon dioxide to the depths." "After the last cars stopped running, much of their exhaust is finally being buried." "Our impact on the climate is declining." "The changes are being felt all around this new world." "In Berlin, young trees attract new life." "The saplings growing out of the concrete provide food for animals." "But where there are deer, hunters are sure to follow." "These wolves have come in from the country." "Most of the wolves in Germany were killed by humans long ago, but these hunters are from Poland." "And wolves aren't the only predators around." "When we disappeared, millions of domesticated dogs had to fight or die." "At first, the dogs had an enormous edge in numbers, but they were facing a battle they couldn't win." "Many of the newly liberated pets were neutered." "Unable to reproduce, they lost their advantage and slowly died out." "But not all dogs disappeared." "Those that managed to survive adapted to the new reality and mated with wolves." "Now they look more like Australian dingoes, medium sized with straight hair and long snouts." "Genetically almost identical, dogs and wolves were kept apart by humans." "But in a world without us, dog and wolf genes are mixing, assuring the future of the canine species." "And this new generation is thriving in cities." "One hundred twenty years after humans disappear, thousands of wolves hunt across Europe." "They need to eat every few days, so they're lured by their prey downtown." "The urban jungle becomes a new killing ground." "There are some places getting colder and whiter than when humans were here." "With no black roads or roofs, some cities definitely suffer the chill." "In northern cities, more snow falls and stays longer." "But packs of wolves and dogs still manage to find food through these cold winters." "South of the freezing temperatures are rivers, diverted by humans for power and commerce." "This is the Thames River, in London, England." "Humans tried to tame it for more than 1000 years." "Once, the Thames was a gateway for thousands of ships." "But its high tides and storm surges often threatened to flood the city." "So, one of the world's largest systems of floodgates was built to hold the waters back." "But without people, the river is out of control." "Tides have sucked boats into bridges, creating dams and forcing the Thames to flow around them." "The banks are flooded." "London returns to the marsh that the Romans found here 2000 years ago." "In the American southwest, the problem is too little water." "This is the Imperial Valley in Southern California." "Once, it provided half of America's winter fruit and vegetables." "With 350 days of sunshine, some crops had four harvests a year." "But only three inches of rain falls annually." "The dry air helps preserve buildings, but it's deadly for crops." "People intervened to make this desert bloom." "Farmers brought in 977 billion gallons of water each year from the Colorado River," "enough to cover every surrounding field in six feet of water." "But when we disappeared, the irrigation stopped." "What was once California's farming miracle is now a barren desert." "Another manmade oasis can be found 300 miles northeast." "Las Vegas." "Built in the middle of a desert, its casinos and fountains used water brought in by electric pumps." "When the power went off, the taps went dry." "Now, with just a few inches of rain a year, the desert is reclaiming the city." "But nature hasn't erased all evidence of our presence." "This is the Colorado River." "It hasn't changed much in the 150 years since we disappeared." "But long ago, it was much deeper and stronger, it even helped carve the Grand Canyon." "Today, the Colorado is still a shadow of its former self." "Dozens of dams were built to harness its strength and keep it from reaching the ocean as a torrent." "Humans also built reservoirs to contain its massive power." "And there the waters will stay as long as the dams can hold the river back." "200 years after humans disappear, nature has taken over many of the world's cities," "but some rivers are still shackled by concrete monoliths." "Dozens of dams still hold back the Colorado River." "The largest of all is the Hoover dam, just 25 miles from Las Vegas." "It's as tall as a seventy story building with a base as thick as two football fields." "Enough concrete was poured to pave a highway from New York to San Francisco." "By blocking the Colorado River, the dam created the reservoir of Lake Mead." "There's enough water here to bury the state of New York under a foot of water." "This is the water that once fed the fountains and swimming pools of Las Vegas." "The Hoover dam is mostly made of solid concrete." "But even this mammoth monument is vulnerable." "The reason lies up the Colorado River near the border of Arizona and Utah." "This is the Glen Canyon dam." "It was created to store water for nearby cities and to generate electricity." "But this dam has a major weakness:" "its spillways, which act like an overflow drain on a bathtub." "If the river level gets too high, the excess water escapes through the spillway tunnels so it doesn't go over the top of the dam." "But the spillways can't handle sudden floods." "The threat is high in the mountains." "When winter storms produce unusually high snowfall, the heavy spring run-off creates surging floodwaters." "They rush head-on to the dam." "After rusting for two centuries, the gates that controlled the spillways have collapsed." "The water races through 700 feet of tunnels deep inside the dam." "And as it does, it creates a destructive pattern." "Low-pressure bubbles form in the water." "When they pop, they cause supersonic explosions that eat through the rock into the dam." "Once, special concrete ramps prevented this from happening." "But after 200 years without humans, erosion has taken over the tunnels." "600 billion cubic feet of water bursts through the dam and gushes downstream." "The surge is over 50 feet high." "It sweeps through the Grand Canyon toward the Hoover Dam, which was built to hold back 45,000 pounds of water per square foot." "This is its greatest test yet." "The water pours over the Hoover dam, sweeping away everything in its path." "The Colorado River rages southward at 25 miles an hour, swamping dozens of dams on its way." "18 hours later it reaches the Gulf of California." "And for the first time in centuries, the Colorado River meets the ocean as a flood, not a stream." "The release of the Colorado will transform this part of North America." "Fish from the ocean will come to this estuary to spawn." "A vast marsh, once one of the wonders of the Americas, will be revitalized." "Hundreds of species will find new homes as river and ocean combine." "Nature is reclaiming the world." "In France, parts of Paris are a marsh again." "In California, irrigated fields have reverted to deserts." "And Manhattan is a forest." "As altered rivers return to their natural state, silt creates new land." "Coastlines change." "South of New Orleans, over 200 square miles of swampland re-emerges, lost when humans dammed up the Mississippi." "Our sudden disappearance is affecting the oceans too." "Once, we took 518 million pounds of fish from the sea every day." "Now, with no trawlers to catch them, fish live longer and grow bigger." "Cod have tripled in size, growing from just a foot or two up to six feet." "Much larger creatures are also recovering in our absence." "Whales are thriving after 200 years without people." "And they've had a lot to recover from." "Before the petroleum industry, whales were a major source of oil for machines and lamps." "Most whale hunting declined when humans started extracting oil from the ground." "But many species remained on the brink of extinction for centuries to come." "The reason:" "large modern ships." "In our last 50 years on earth, the number of ships worldwide doubled." "So did the noise they generated." "Some of the sound from these vessels carried for miles under the oceans." "As a result, whales could no longer hear each other's mating calls, and they rely on sound to find mates up to a thousand miles away." "With humans gone, whales' mating songs are being heard from Canada to the Caribbean." "After 200 years, our impact here is vanishing." "The oceans once again teem with life." "But on land there are still relics of humanity that remain." "We built symbols of our power when we ruled the earth." "But how long will they last?" "It's now 230 years after humans disappear." "Few signs remain that an intelligent, creative species once lived here." "One of the grandest is also one of the world's most recognizable modern monuments:" "the Eiffel Tower." "Over a thousand feet tall, it was constructed in 1889 for a world exhibition and was meant to be torn down twenty years later." "But the French fell in love with their Tower, and it became one of the most famous landmarks in the world." "This 19th century marvel of construction was designed by bridge builders, and it's been standing now for centuries, outlasting even modern skyscrapers." "The lattice structure gives the Tower strength without using much metal." "And the entire tower weighs just 7,300 tons." "When people were still around, the Eiffel Tower was covered in 60 tons of paint to protect it from the elements." "But 230 years of weather has taken its toll." "Rain has flaked away the paint." "Rust eats away at the Tower's iron." "With every rainstorm, the entire structure erodes and becomes more brittle." "Now, the Tower is vulnerable even to moderate winds." "Normally, its support beams can withstand these winds, but now, they're too weak." "Three centuries after it was built, the Tower comes crashing down." "Paris's landscape changes forever." "Monuments and buildings can't adapt to this new world;" "they're frozen by the techniques used to create them." "But species can evolve as conditions change." "Here, in the forests of Paris, animals that we left behind have adapted." "Most of these pigs are descendants of pink pigs." "They thrive in the shadow of the ruined Eiffel Tower." "These feral pigs bred with surving domesticated ones to create a hearty, tough animal with dark fur." "They are survivors in the new world without us." "Even while the modern world collapses around them, those that adapt survive." "Another symbol of human ingenuity stands on the other side of the Atlantic." "How has it changed in the two hundred thirty years since we vanished?" "The Statue of Liberty was built in 1886 of massive copper plates." "She's three years older than the Eiffel Tower." "Since humans disappeared, some parts of her are faring better than before." "Acid rain used to eat away at her skin, stripping her of one pound of copper every year." "Pollution coated her nose and cheeks with black grime." "But cleaner skies have led to a cleaner statue." "Liberty's skin has benefited from the absence of humans, but other parts of her body haven't." "Over the centuries, a forest has grown up around her and it's littered with copper plates." "The plates are about as thick as two pennies and can last a thousand years." "So why is the Statue of Liberty losing her skin?" "After 230 years, the statue's arm has finally collapsed." "If copper is the statue's skin, iron bars are its skeleton." "And like the Eiffel Tower, these iron bars have rusted through." "The shoulder bars became too weak to hold up the arm and its torch." "Now, this symbol of freedom is only visible to wildlife." "The Statue's arm and torch were first to fall, but that was just the beginning." "More than two hundred years have taken their toll on some of our most iconic monuments." "It's only a matter of time before they disappear forever." "Signs of the human species are becoming harder to find in North America." "The eastern half of the continent is covered by immense forests." "Without us to cut them down, trees are growing 90 feet tall and blocking the sunlight." "But the trees do more than tower above old suburbs and roads, they bury them." "After two hundred thirty years, falling leaves have created three feet of new soil and cover nearly everything we left behind." "Occasionally, rain-swollen streams reveal the remains of human existence." "This is all that's left of a home, centuries after the wooden beams and floors rotted away." "Plastic from modern houses also litters the ground." "This cell phone is still intact, more than 200 years after the last phone call." "It may survive for centuries." "Most metals have rusted through, but stainless steel is truly stainless." "This kitchen sink may last for thousands of years, but for animals to last," "some need to adapt." "In the West, caribou and deer roam over millions of acres of former farm land." "And once again, so do the thunderous hooves of bison." "Their herds can grow by 30 percent a year." "From a species of half a million, their numbers are now reaching into the tens of millions." "Other creatures also dot the savannahs of the American West." "These furry beasts are the descendants of millions of beef cattle." "Their ancestors mated with Highland cows, a breed insulated with fur, not fat." "Horses evolved here long before humans arrived, and once again they run wild and free." "In just 230 years," "North America has buried human homes and lost some of its most prized monuments." "And time doesn't stop," "1000 years after every human disappeared from Earth," "the iron of the Eiffel Tower is almost gone." "It has slowly eroded and become part of the Seine." "In New York, the Statue of Liberty has fallen into the forest." "Her iron skeleton finally gave way and her body collapsed." "But her pedestal still towers above the trees around it." "Made of solid concrete and granite, it wil last thousands of years." "But time can wipe away all evidence of humanity, especially as the world turns colder." "A new ice age grips the planet." "Gradual changes in the Earth's orbit take it further from the sun." "Snow will stay on the ground in northern cities for two summers in a row." "Then, a chain reaction causes ice to cover most of the northern hemisphere." "It will stay here for the next hundred thousand years." "Once again, glaciers travel south and eventually reach Manhattan." "They'll grind down what's left of the Statue of Liberty and any other sign of human civilization left in the north." "But there is one place our imprint will remain indefinitely." "On the Moon." "Unlike Earth, the moon's landscape changes very slowly." "Craters more than 4 billion years old are still preserved." "Along with some human artifacts." "A car." "A television camera." "The only reminders of the human species that will last for millions of years aren't even found on Earth." "Planet Earth is four point five billion years old." "In that context, human civilization is just the blink of an eye." "It took us 10,000 years to cut down half of the world's forests," "but after we disappear, they grow back in just 500 years." "Once we used half of all fresh water and changed the course of half of the world's major rivers." "But some dams were washed away in just 200 years." "We pumped 13.5 billion tons of carbon dioxide into the air each year." "But in just a couple hundred years, plants and oceans were scrubbing the earth clean." "It took just over a century for our major cities to start crumbling," "for forests and swamps to cover what used to be concrete and asphalt." "The planet was even able to handle the nuclear legacy we left behind." "After we disappeared, thousands of tons of radioactive particles were released." "But nature was able to bury most of it, and some animal species not only survived, they thrived." "Earth is resilient." "And time, it cleaned up every mess we left behind" "All we had to do... was get out of the way."