In a post-apocalyptic future, even sealed artifacts such as the Liberty Bell and the United States Declaration of Independence in Philadelphia, Pennsylvania and the Svalbard Global Seed Vault in Norway will not survive indefinitely. Wolves and feral dogs struggle to survive. In San Francisco cables snap on the Golden Gate Bridge and the cable cars are sent careening through the streets, while the Petronas Twin Towers in Kuala Lumpur survive longer than most other modern towers. In Paris, the fate of the Mona Lisa, the prehistoric Lascaux caves, the modern Lascaux II replica, the Venus de Milo and the Notre Dame de Paris is shown. The episode also examines Centralia, Pennsylvania, which was largely abandoned in 1984 because of a coal seam fire burning beneath the town.
1 day after people, the Declaration of Independence is housed in the West Wing of Inependence Hall in Philadelphia. Of the 200 copies printed on the 4th of July 1776, just 25 survive. This one prized because it was the first to be read aloud in public is now virtually entombed. Without power, humidity will creep into the case and threaten the document, but unlike today's paper, made of celluose from trees, 18th century paper has natural cotten and linen fibres that make it stronger. Just across the street is the bell that hung above the room where the Declaration of Independence was signed in 1776, the Liberty Bell, still heavily protected by two thick marble walls. The design of the walls is a heavily guarded secret, but they've been engineered to withstand extreme shock.
Almost 4000 miles away at the Louvre Musuem, in Paris, Leonardo da Vinci's Mona Lisa faces its own risk from within. Painted on wood it can swell and shrink. The painting is protected by an airtight case that can withstand a rocket propelled grenade, sensors in the case can detect the tiniest swelling in the wood. This treasure with the famous smile is buried under layers of protection, but how long will they last?
While some icons have been left buried, others are left bound. San Francisco's cable-cars are out of service. In the time of humans, they were pulled up and down some of the world's steepest urban hills by a wire cable. 1 day after people, the pulleys stop, the world famous cable-cars are frozen in their tracks, hanging up a wire thread, for now.
Arching across the water, 2 bridges, the Golden Gate and the San Francisco Oakland Bay are strangely silent. In the time if humans, the Golden Gate was an engineering marvel, crossed by 1008 cars every day, but 2 days after people the only thing crossing the bridge is a single, silent assassin. To the East the Bay Bridge stretches more than four miles connecting San Franciso to Oakland, no single bridge could span that distance, so in 1933, engineers solved the problem by building a series of bridges, a causeway section, a cantilever in the middle and a double suspension design for the deepest part over the shipping channel. After a section of collapsed in a 1989 earthquake, the bridge was retro-fitted with new bolts, plates and steel. Studier than ever, 2 days after humans, its only traffic is dust, and that will bring its own challenges.
The only sounds to be heard from the waterfront are wavelets lapping at the hull of a cargo ship. Despite the explosion of technology, in the time of humans, ships were tied to the pier with the same piece if equipment used by ancient mariners. 2 days after people, eight ropes made of a synthetic as strong as wire secure the vessel to the deserted pier, a single line can hold fast 55 tonnes, but for how long, that remains to be seen.
It's 1 week after people, the Petronas Towers soar over the deserted city of Kuala Lumpur in Malaysia, they're the world's tallest twin buildings, connected by the highest skybridge ever built. In two separate events, human spiderman, Alain Robert tried to scale one of the 1483 foot towers with his bare hands, both times he climbed 60 floors before allowing himself to be apprehended. Now, only the sun climbs its walls.
Amid the remains of civilisation there are survivors. In North America, a pungent smell of old food left in kitchens attracts all sorts of hungry animals. 14 days after people, some of the 400,000 wolves living in the wild invade homes for an easy meal. While the wolves are moving in, dogs are trying to move out, but these animals remain bound to humans. But one kind of canine would be ideally suited to this new world, the stray dog. Belonging to no-one, they live on the outskirts of towns and are lean survival machines. For the first few months after people large populations of stray dogs live, eat and battle for the mountains of food at landfills and dumps, after that, survival becomes a riskier proposition.
It's 3 months into a life after people, the breath-taking prehistoric paintings and ingravings in the Lachaux caves in southern France, thought to have been drawn by pro-magnon man 30,000 years ago were discovered in 1940. Undisturbed again, they could survive for thousands more years, so long as they stay buried. But for how long will the other treasures of our civilisation remain secure, when will others come unbound and what will happen to a site called the Doomsday Vault?
4 months after people, in the frozen wastes of Norway's most northernly islands, a doorway in the snow leads to a mysterious crypt, known as the Doomsday Vault, it was meant to secure the world against a disaster that is now happening in a life after people. That disaster was sparked in the time of humans by the need to feed an exploding population. Agricultural companies engineered seeds to produce super-crops and maximise output. Huge tracks of farmland were planted with the single best variety of seed, but this sacrifices crop's strongest protection against pests, diversity. In the time of humans, farmers protected their crops with pesticides, 4 months after people there is nothing to stop a single species of insect from mowing down hundreds of thousands of acres. The vault in Norway, called the Svalvard Global Seed Vault was built for precisely this kind of doomsday plague, with the capacity to store a billion seeds and millions of different kinds, it can bring life back to Earth. In the time of humans, an artificial cooling system chilled the vault to -4 degrees, perfect for seed storage, since the electricity failed the vault has been warming up, it will stabilize at 25 degrees, the temperature of the surrounding permafrost, but how long can the seeds now survive?
2 years after people, a cable-car in San Francisco is about to become gravity's bullet train, the inner core of the cables that run beneath the streets is made of plain rope. After two years, it was rotted away, the car has broken free and becomes an eight-tonne mini missile of wood and steel.
Across the bay, eight high-strength lines have held the massive cargo ship fast for two years. In a howling gale, the rope will be put to the ultimate test. 50,000 tonnes rocked by wind and waves generates tremendous stress and a line snaps, once the first line snaps, the others swiftly follow, and the ship sets a course for disaster.
10 years after people, the Declaration of Indepenence in Philadelphia is exposed to an enemy far worse than the British redcoats, the windows of Indepdence Hall's wets wing were covered with panels to keep out the caustic rays of sunlight. The failure of a single window pane is all that's necessary to put the Declaration in harm's way. With nothing to stop it, the wind makes quick work of the panels, daylight streams into the building, the words of the Declaration are beginning to disappear.
Across the Atlantic Ocean, something msyterious is stating to happen to a priceless treasure. The prehistoric art in the Lachaux caves is decaying, the cave's walls are flaking, how could caves that have survived 30,000 years now be fading so fast? The answer is that this is not the original cave, the original was damaged by the effects of too many visitors, so the French built an exact replica for tourists in 1983 and called it Lachaux II. But now, just 10 years after people, its steel and plaster construction is falling apart. Just the opposite is happening to the original cave, without the body heat and daily disturbances of people, the caves that were dubbed the Sistine Chapel of the Ice Age have returned to a natural balance. What was created by prehistoric man wil far outlast the recreation built by modern man. The Ice Age paintings will endure because of their underground vault, but for one small American town that is already 25 years into a life after people, it was an underground disaster that brought about its demise.
25 years after people, in a windswept park an engraved stone marks a mysterious vault, it appears to refer to a town and yet, there's almost nothing there. Battered signs mark streets and regulate parking, but there are no cars. Graveyard walls are in disarray, streets are paved and lined with curbs, but there are no structures, except for the occasional house. A nearby road is bizarrely buckled, as if seized by a strange force of nature. This indeed was once a thriving town, called Centralia, but what happened? In 1983, Centralia hummed with more than 1000 residents, businesses, churches and a school anchored the village, Highway 61 was its main street. But something was terribly wrong, located in the heart of Pennsylvania's coal country, Centralia had always lived by mining. Now, it was about to die from it. For more than 20 years, a hellish underground fire had been burning in a maze of abandoned coal shafts that ran directly beneath the town, deadly gases seeped into the homes above the fires leaving residents little choice, but to leave. In 1984, the Federal government bought up hundreds of homes and a mass exodus began, but a handful of residents refused to leave. In many abandoned towns, the first job for nature is to tear down the structures left behind, in Centralia man gave nature a headstart, almost all the buildings were demolished and nature was left to take over. 25 years later, vines grow over a rusting trailer home, inside the debris strewen floors are chewed away by moisture, plastic Christmas ornaments have largely withstood the assault of snow and rain, but their holiday dazzle has faded. Stone walls are surrendering to gravity, trees, grass and shrubs have seized the oppurtunity presented by empty spaces, leaving just a few relics of the human past still visible. The sub-terrian inferno burned beneath the stretch of the man highway at the edge of the old town, ominous cracks erupted in the road and forced the state to reroute it. 25 years later, the fire has torn a huge fissure in the old road, sulphurous smoke and steam still rises up, moss grows in the warm vent sheltered from the bitter winters. The roadway has grotesquely buckled from the underground cave-ins caused by the blaze. 100 yards up the road, where both humans and fire have moved on, thick trees grow in the middle of the abandoned pavement. Cobwebs and dust cover the last abandoned house in the town, its destruction imminent. The basement is an underworld, strewen with the remnants of family's possessions. The windows offer a haunting view of nowhere. Centrlia is the ultimate ghost town. On the outskirts of town, pipes that were thrust into the ground in an attempt to vent the fire's lethal gases lie rusted and overgrown. The iron gates of the cemetary close to where the fire first broke out have oxidised over the years. The wooden roof of a warehouse down the road is riddled with rot and no longer provides any shelter, but the cinderblock walls will stand for several more decades until the mortar crumbles and the bricks collapse. Beneath it all, largely unseen, the fire quietly rages underground, it will continue to burn for another 250 years, long after Centralia is gone. There's one final legacy, also underground, marked by the engraved stone in what was once the centre of the town, it's a time capsule, buried nearly 50 years ago it's due to be unearthed in 2016, its contents may be the last mystery before the land returns to wilderness, forever.
It's 50 years after people, in the frozen land of Norway, plantlife is beginning to perish in a structure that was meant to preserve it. The first seeds have begun to die in the Svalbald Global Seed Vault. Scientists believe that seeds have a special anti-aging protein, when that protein fails, the seeds die, a bit like corroded rebar in a concrete column, it causes a structual break-down in the seed. In the cold dark stillness of the vault it may well be the collapse of these proteins that makes lettuce seeds the first casulty.
75 years of steamy, tropical heat have corroded a part of the Petronas Towers where steel is vital, the supports under the skybridge. The corrosion buckles a supporting leg, turning the skybridge into a one-way lift. The twin towers made of super-strength columns remain intact, but their connection to each other is severed forever.
Thousands of miles away in Philadelphia, the Liberty Bell is about to ring one last time. Made of bronze it can last thousands of years, bu the structural integrity is threatened by its large crack and a much less visible one that could be just as damaging. It's the wooden support that holds the bells where the final split will begin, made from elm, 75 years of moisture and insects have left it too weak to hold the weight of the one-tonne bell. Though split in two, the symbol of freedom remains clearly recognizable.
A kind of freedom has become the very essence of stray dogs. Once dependent on human leftovers on the streets, they've evolved back into the wild predators before domestication. Dingos were bought to Australia in around 2000 B.C as domesticated dogs, released into the Outback they soon numbered hundreds of thousands. But without humans who provided them with most of their food stray dogs have seen their population decimated. Where once there were more than 300,000,000, there are now just a few million. But as a species they will survive because of a unique running ability that distinguishes them from every other creature in the animal kingdom.
100 years after people, the crucible steel of the mighty Golden Gate Bridge has been humbled by common oxygen. Dense fogs feed the rust which threatens at the point of highest stress, the vertical cables that bear the crushing weight of the deck. The failure of one cable quickly triggers others around it. Unsupported the roadway plunges 245 feet into the chill grey waters of the bay.
Only a few miles to the east, the Bay Bridge is in a dryer and warmer location, this slows rust, but the moisture triggers another kind of growth. Without maintenance to clear the fledgling forest, dirt clogs the expansion joints. With no room for movement, one span's fate is sealed.
Inside the Louvre, the protective case entombing the Mona Lisa was built to withstand a terrorist attack, but humble dust will infiltrate the neo-preen seals, forging a path for moisture. The dampness sounds a death knell for the painting, as it creates the perfect habitat with a tiny insect called the Deathwatch Beetle. In fact the beetles have nothing to do with dying, usually. But the Mona Lisa is painted on wood, and these are wood-eating beetles. The Mona Lisa's fate is just the beginning of civilisation's demise, soon the fate of an entire city will be sealed.
It's now 200 years after people, only the skeltal spectre of the Golden Gate's soaring towers remain, but by the shallows of the Bay Bridge enough debris has built up around the piers to form a more permanent passage.
300 years after people, rain has spawned a new occupying force in historic Philadelphia, a dense forest. Amid the trees, the two blast walls rise out of the earth and surround the half-buried Liberty Bell. As the forest buries the bell, the inscription may be one of the last visible pieces.
100 yards away, the Declaration of Independence lies among the rubble of the west win still intact in its bullet-proof casing. The case, built to withstand the blow of a sledgehammer has shielded the document since the year 2000, but heat and light left the linen rag paper brittle and desiccated. Three centures after people, the first blast of air to penertrate through a worn seam of the case will cause the document to disentergrate.
500 years after people, the Petronas Towers may be the tallest manmade structure still standing on Earth, thanks to an extraordinary quirk in their design. They were the tallest buildings in the world to be supported by a frame of concrete. Five centuries of exposure to tropical sun and torrid humidity have weakened the super-strength cement. The collapse begins at where the columns are at their most narrow, at the top. Cascading debris from one tower triggers the collapse of the other. In seconds the monumental structures are reduced to dust and rubble. It's only a matter of years before walls of jungle entomb every trace of the once mighty buildings.
2000 years after people, the Mona Lisa is long gone, but there was also another famous woman in the Louvre, Venus de Milo. The six-foot statue was buried for nearly two millennia before she was unearthed in 1820 by a farmer. Now she is being slowly reburied, sculpted from marble the ancient godess of love was built to last. Just across the river from where the Louvre once stood the medieval cathedral of Notre Dame also remains. Built entirely of stone, it is held together by the eternal force of gravity.
20,000 years after people, the last of the hundreds of millions of seeds stored in the Global Seed Vault have died. Their potential to generate new life is gone forever, for the contents of this vault doomsday has arrived.
10 million years after people, could the remains of the once great city of San Francisco be fossilized like the bones of the dinosaurs? For fossilization to occur, buildings like bones need to be buried before they erode away. Their fate is decided by whether large sections of the Earth's crust on which they sit are pushing the ground up or down. In regions where the Earth's crust is slowly rising, the surface erodes wiping away the remains of human civilisation, but where parts of the crust are moving downwards, under the sea or into the Earth remains are buried and the forces of fossilisation can begin. In the time of humans San Francisco was perched along the San Andreas fault, which marked the boundary between teo large tetonic plates. This spot on Earth once triggered punishing earthhquakes, now in the extreme slow motion of geological movement it has delivered the ultimate blow.
Worldly goods prove fleeting, the surface of the Earth is no place for the artifacts of man in a life after people.