The Invaders is the fifth episode of season one of Life After People: The Series. It originally aired on May 20, 2009.


After the disappearance of man, sandstorms could sweep through Phoenix, Miami and Shanghai might disappear into the ocean, and invasive plants and animals such as Burmese Pythons will spread uncontrolled. Also included is the fate of the Taj Mahal in India, the Kennedy Space Center, the Grand Canyon Skywalk, and the Seven Mile Bridge in the Florida Keys. The episode also explores Tyneham, England, which was abandoned by people in 1943 during World War II in preparation for the D-Day landings.


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 before these invasive species conquer the world?

1 day after people, the invaders are on the move. In the 2500 square miles of marshes and swamps that make up Florida's Everglades, the ancient domain of alligators is being 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 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. 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 would catch and remove them. With no humans to control their spread can anything stop the pythons? There are more than 4000 invasive species in the United States alone, killer plants as well as animals.

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. Only people could control their spread, now the invasive species are winning the battle by forfeit.

Some of the most aggresive invaders are also the smallest, 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, devouring everything in their path, organic matter, food, wood and the carcasses of animals left behind in the absence of man. Predators of the dead, large and small, are feasting. Other vermin attack living animals, including millions of dogs who depended on humans to keep them healthy and who must now 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 dog tracks around the United States. In Florida, one group is now roaming free. Often fed raw meat to increase their competitiveness instinct when chasing mechanical rabbits, the escaped greyhounds are now hunting live rabbits, as well as rats. These dogs track with their eyes, not their noses. They also scavenge for food, but this often requires co-operation and greyhounds have been trained to beat their competitors at any cost. 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 are attacking New York. The Asian long-horned beetle arrived in New York from China in the mid-1990s probably stowed away in some cargo. They quickly started chomping on the trees of New York City requireing a massive eradication effort. The larvae of these inch and a half long insects are miniature bio-fuel factories, fungus in their gut somehow helps them convert wood into energy, this is so unique that scientists have studied them to discover how we might derive ethanol from trees. Invasive species and extreme forces are beginning 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 Grand Canyon and across the desert Phoenix, Arizona will face a cascading series of disasters.

1 month after people, the disaster begins as Phoenix is invaded by a heatwave 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. Concrete absorbs 60% of the Sun's heat and light, but asphalt can absorb 90% and because of its density, retains much of that heat after dark. 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. But without people the waste water plants have all shut down.

6 months after people, the Phoenix lakes have evaporated, next will be the rivers. As Arizona dries up, water floods other cities and undermines great towers, while elsewhere alligators fight to defend their territory from the invading pythons, what will happen when these monsters clash?

It's 1 year into a life after people, alligators still rule The Everglades, but the invasion of Burmese pythons is heating up, and pythons have the advantage of size. Anything includes alligators, in 2005 researchers in The Everglades discovered the aftermath of a grisly attack in which an 8 foot alligator had been devoured by a 14 foot Burmese python. But alligators don't give up without a fight. A year after people, the half a million native alligators still outnumber the 30,000 invasive pythons, but they will not do so forever.

All around the world invasive predators and extreme forces are transforming our cities. In Shanghai, the Oriental Pearl Tower rises 1535 feet into the sky along the Huangpu River. The third tallest TV and radio tower in the world it also housed a hotel, a shopping mall and a revolving restraunt. In the time of humans, more than 3000 highrises were built in Shanghai in less than 20 years, by 2003 the weight of the buildings was making Shanghai sink by more than half an 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 civilisation in their new lives. They may use our debris as tools, but will their experience with humans live on in other ways? The centre of Miami has a lot of new tennants, 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, setting the stage for a startling evolutionary breakthrough. While most chimpanzees greedily eat every egg, a few take a more long-term approach. By doing this the chimps ensure that new generations of birds will hatch to continue supplying them with eggs, the chimps also protect their birds from the feral cats that hunt in the building's hallways. And so apes take the first steps towards animal husbandry, one of the basic aspects of human civilisation and the 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 leading to the end of another civilisation. 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. A population that may have been as high as 50,000 completely disappeared, now the remnants left by Phoenix's 1.5 million inhabitants are venerable to the same devastating forces. Phoenix faces recurrent invasions from summertime torrents of soil, sand and dust, called Habbo meaning sandstorm in Arabic. Manm-ade rivers and irrigation canals have long vanished, top soil is dry and loose adding more dust to the wind and making duststorms in a life after people more lethal than before. Acres of dust invade the broken buildings, office floors become deserts, but they're only dry for a while because after the duststorms come the monsoon rains, triggered by thr heat rising from the Phoenix pavement. The driving rains sand and dust fill derelict buildings with mud. In the time of humans emergency services would've cleared the debris, with people gone the mud fills the offices of Phoenix's business district, creating another problem, mud is heavier than soil and if there's too much mud the buildings won't survive for much longer.

20 years after people, giants suaves of Miami are being buried by aggreively growing invasive plants. With no-one to stop its spread the Christmas decoration is a year-round threat to cities. The Brazialian pepper is joined in its attack by invading waves of Lygodium, a climbing vines from Australia that can grow 100 feet. In a life after people the invaders are on the march, one village on Earth was abondoned 65 years ago because of an invasion of a different kind.

65 years into a life after people, nature continues to invade man's structures, pulling down roofs and tearing apart walls. Nestling in a Dorset valley is the lost village of Tyneham, where time has stood still. People lived and farmed here for more than 5000 years, in 1939 war broke out. In December 1943 when the War Office needed more land for firing practise the 252 residents were asked to leave, albeit temporarily and were told they could return at the end of the war. In 1948 the War Office took out a compulsory purchase on the land, the village has been empty ever since invaded by the natural world. Stone farmhouses built in the early 19th century show how time and the seasons can destroy what humans have built. Tyneham bears the scars of an aggresive invader. It's the work of a creature that can claw through 3 feet of earth in less than a minute, the European Badger. Badgers are among the world's fastest diggers and have been known to create tunnels systems as much as 1000 feet long. Creatures more rare than badgers also call Tyneham home, in the absence of humans and their poisons and pesticides animals are thriving. There's one animal that actaully protects Tyneham from complete conquest, the army allows grazing sheep from nearby farms to keep the grass short, wothout the sheep the valley would begin to return to its ancient condition. 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 where they originally came. In several thousand years geological processes will complete the invasion of Tyneham.

Around the world the forces of destruction are gaining the upper hand, as man's works are overthrown by hurricanes and invasive species.

70 years into a life after people, these are the last days of Shanghai's Oriental Pearl Tower. In the time of humans it dominated the skyline of China's largest 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 3 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 100 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 sqaure block business district, once the financial centre of Arizona is a chaos of mud and debris. Mud-filled floors crash and tumble and the piled up debris collapses the towers from within. The tower's 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, other are eaten from below. In the time of humans more than 1000 miles of man-made earthern barriers controlled flooding in The Everglades, but thousands of sailfin catfish, descendants of pets brought from South America in the 1970s have invaded the dykes and levees digging 3 foot deep burrows to lay their eggs. 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. Even in the times of humans, alligators were always at its gates and launchpads from the dawn of space exploration were already abondoned and rusting, now the remaining structures and rockets are the victims of repeated South Florida hurricanes and the only creatures waiting to launch from here are hungry vultures.

196 miles up the coast, Miami has run out of beach, it's a reversial of fortune for a place that began life around 1914 when developers began filling in over two and half thousand acres of mangrove swamp around a narrow coastal sandbar to create a high-class beach resort, but the creation of Miami beach contained the seeds of its destruction. By the late 20th century so much of the coast ha been eaten away that some hotels lost 80% of their beachfront. In a battle against time and the Atlantic, in the early 1970s engineers brought in millions of tonnes of new sand, one century after people the invading ocean is unopposed as it swallows the foundations of once luxurious hotels. The former hotels fall into each other before finally toppling into the waiting grasp of the Atlantic.

Even greater changes are in store, what does the future hold for man's most gravity defying and supposedly eternal structures? Which invaders pervail and what will be man's ultimate legacy?

150 years after people, Burmese pythons dominate The Everglades and they've invaded fresh territories, capable of living in more varied climates than alligators and even able to climb trees, the pythons now dominate the lower 40% of what was once Florida.

200 years after people, cities like Phoenix barely exist, elsewhere in Arizona some desert structures still stand, but not for long. The Skywalk, unvailed in 2007 is a 4 inch thick 70 foot long glass plate set 4000 feet above the Grand Canyon anchored with 500 tonnes of steel beams two and half inches thick. It used to be checked every day for cracks and flaws, but in a life after people 200 years of corrosion have rotted away the steel supports. It takes the Skywalk only 15 seconds to plummet to the canyon floor.

In Miami, the skyline is gone, only a few rusted girders still point skywards. Now living in Florida's sub-tropical jungle these chimpanzees are the decendants 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 to produce more birds and more eggs. It was once thought that humans were the only species that could pass on learned behaviour and traditions to subsequent generations, but research in the late 20th and early 21st centuries showed that chimpanzees share this ability, setting the stage for the possibility that these chimps may forge a civilisation of their own. Whether or not this chimpanzee tribe complete the multi-million year evolutionary journey that led to the first humans the use of tools and domesticated could make these apes the dominant lifeforms 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 building in the city of Agra 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 over India's most dangerous seismic zone. As a giant quake liquefies the clay soil, the minerettes fall away and the stone and marble collapse.

2000 years after people, the desert that has buried Phoenix has itself been transformed. 2000 years of rain and snow have recharged the water table, bringing the underground aquafer to the surface and feeding the rivers again, with no humans using the water Phoenix is a vast savannah just as it was after the last Ice Age. Beasts that once avoided people hunt as if they never existed, the animals have forgotten humans, or have they?

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? While dolphins were native to these waters many of the creatures that thrive in the absence of humans will be invaders from other lands.

Old habitats have new rulers. Familair 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 fight for land, for survival, for life after people.

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