"NARRATOR:" "Ninety degrees west." "One degree south." "A world lost in the vastness of the Pacific." "(BIRDS CHIRPING)" "Home to the strangest life imaginable." "Governed by nature's brutal forces." "Islands which have transformed our understanding of life on Earth." "Galápagos lies remote, 600 miles off the coast of South America, astride the equator." "A scattering of 1 3 main islands, with more than 1 00 islets, rocks and reefs." "Each island has its own character." "Some are cloaked in forest, concealing life." "(BIRDS TWITTERING)" "Others, smouldering giants, rugged and austere." "Haunt of pirates." "Lair of dragons." "All are the creation of one of the strangest features found anywhere on our planet." "Galápagos are no ordinary islands." "A mysterious, prehistoric world." "A landscape that profoundly influences life." "These islands are plumbed directly into the heart of the Earth." "An artery of superheated rock rises to the surface, from hundreds of miles beneath the crust." "It's a volcanic hotspot." "Galápagos constantly simmers, even beneath the waves." "These tiny bubbles of gas give a vital clue to the genesis of the islands." "Sea vents are like pressure valves, releasing growing tension from chambers of molten rock beneath the crust." "But if the pressure gets too much, this magma reaches bursting point." "(EXPLOSION)" "The largest of all the Galápagos volcanoes, Sierra Negra, recently blew smoke and ash seven miles into the sky." "The only rivers here are rivers of red hot rock, at a scorching 1 1 00 degrees Celsius." "Galápagos is one of the most volcanic places on Earth." "The hotspot has been active for millions of years, building island after island." "But it's not just how these islands are born, but where they are born that makes Galápagos so special." "They've emerged at the crossroads of four major ocean currents, sweeping in from all corners of the Pacific." "This interplay of warm and cold currents, generates an extraordinary diversity of marine life." "Over 500 species of fish make the most of these plankton-rich waters." "Among them, residents like these barnacle blennies" "and strange garden eels." "Even ocean travellers like scalloped hammerheads gather in huge numbers." "The converging currents that envelop Galápagos have also brought creatures to these shores from opposite ends of the Pacific." "Galápagos sea lions are related to Californian sea lions, that came here from the north." "And from as far south as the subantarctic, swam the ancestors of these birds," "Galápagos penguins." "The cold waters here allow them to survive on the equator." "Fish shoals like these seek refuge from open ocean predators by keeping near the shoreline." "But in Galápagos this strategy can be risky." "The coastal margins are the feeding grounds for the most aerobatic hunters," "Blue-footed Boobies." "When the fishing's good, they gather in their thousands." "Piercing calls synchronise an assault." "(SCREECHING)" "Plunging in unison overwhelms their prey." "Blue-footed Boobies can dive in waters just three feet deep." "But as they chase the shoals further inshore, they risk treacherous undercurrents and hidden rocks." "But the biggest hazard is the battering surf." "A wing smashed by the breakers means slow and certain death." "Ghost crabs normally sift the sand for food, but they've always got an eye out for something meatier." "For creatures of the sea and air, Galápagos is a welcome sanctuary." "But these islands are not a choice destination for land animals." "Those that came here were probably victims of flash floods, swept out from the mainland on rafts of floating trees," "crossing 600 miles of ocean with no food and no fresh water." "For any survivor, landing in a place like this would be a daunting prospect." "Fernandina is the harshest, most volcanically active of all the Galápagos islands, a lava-scarred giant." "This is a single, monumental volcano with a caldera half a mile deep and nearly four miles wide." "Where the volcano meets the sea, dragons stir." "It's hard to tell reptile from rock." "These creatures are found nowhere else on Earth." "At dawn, the cold-blooded iguanas thaw from the night's chill, absorbing the heat of the equatorial sun." "When they've warmed, the coastline of Fernandina comes alive." "On this island, food is scarce" "and the only way to find it involves a mission that seems suicidal." "Only the larger adults dare to take the plunge." "Marine iguanas are strong swimmers." "With a single breath, they can comfortably dive to 30 feet." "And all this effort for red and green algae, which thrive in the cold water." "Marine iguanas are the world's only sea lizards, but when their distant ancestors were washed ashore in Galápagos, they were land animals." "To survive, they were forced to tackle the ocean." "This male must graze as quickly as he can." "In these chilling waters, his body temperature falls fast." "A 1 0-minute dive is about the most he can manage before his muscles seize up." "Fighting the surge back to the shore is a Herculean task." "And to make matters worse, he must now run the gauntlet of sea lions." "They' re the last thing the iguana needs." "No harm is meant." "It's nothing more than a rather one-sided game of cat-and-mouse." "Marine iguanas take in too much salt with their food." "But with the help of special glands, they sneeze it out." "They also welcome these resourceful visitors." "Sally Lightfoot crabs like to groom them for algae, parasites and dead skin." "Lava lizards, far smaller reptilian relatives, have found their own ingenious ways to get by on this fierce shoreline." "They enjoy a special relationship with the sea lions." "The lizards rid them of flies, which can be a ticklish nuisance." "(FLIES BUZZING)" "This sea lion accepts these predatory lizards." "Both benefit." "Survival depends on seizing every opportunity in this volcanic wasteland." "Fernandina is the youngest of all the main Galápagos Islands." "It may have raised its head above the waves as recently as 30,000 years ago." "It sits right above the volcanic hotspot, in the far west of the archipelago." "But how is it that the other islands, created at this same hotspot, are now scattered over hundreds of miles of ocean to the east?" "All the islands are moving." "(BIRD SQUAWKING)" "They' re travelling south-east at an inch or two a year on a massive tectonic plate which continually slides over the hotspot." "Their journey begins as soon as they' re born." "And in their wake, new islands emerge." "It's like a geological conveyor belt." "So the archipelago we see today is just a snapshot in time." "The oldest islands are in the east, the youngest in the west." "And as Fernandina ages, it will be carried on this conveyor belt to where the biggest of all the Galápagos Islands currently resides," "Isabela." "It's shaped like a giant seahorse, almost 1 00 miles long, with a backbone of volcanoes." "Isabela is a teenage Galápagos island, nearing a million years old." "Time enough for life to settle." "Its giant calderas still tower more than a mile above sea level and are draped in vegetation." "(BIRDS CHIRPING)" "Although Isabela is softening with age, it's still close enough to the hotspot to remain active." "On its summits, like here on Alcedo Volcano, live the most iconic of all Galápagos animals." "Their ancient trails, carved over tens of thousands of years, scar the landscape." "Giant tortoises." "They are the largest of their kind in the world, weighing up to 5 50 pounds." "Water is a scarce resource on this island, and giant tortoises can survive months without it." "But during the wetter season, they gather to quench their thirst among a scattering of freshwater pools." "A tortoise oasis." "Around 5,000 live here on Alcedo." "It's the greatest concentration found anywhere in Galápagos." "Despite their extensive body armour, tortoises are vulnerable to skin parasites, which they are unable to remove themselves." "So they've developed a remarkable relationship with finches." "When they need a service, it's a sort of slow-motion pit stop." "A finch feeding frenzy." "This giant tortoise could live to be 1 50 years old." "During his lifetime, the island he roams, Isabela, will be transported about 20 feet south-east, on the Galápagos conveyor belt." "But a million years from now, that's about 6,000 tortoise lifetimes," "Isabela will be carried right to the heart of the Galápagos archipelago, to where these mature, middle-aged islands now lie." "Santa Cruz has been pulled so far from the hotspot that its volcanoes are now ancient ruins, worn by the passage of time and swallowed by forest." "(BIRDS CHIRPING)" "Plants and soils now cover this ageing island, teeming with life." "Its peaks are still high enough to generate clouds and receive regular rainfall." "It's one of the few places in Galápagos where there are magical freshwater pools." "After a morning spent foraging at sea, frigate birds come here to bathe their feathers" "and to sip on the wing." "These forest basins are created by layer on layer of rich volcanic soil packed over porous lava." "Elsewhere, the water filters its way through, to re-emerge near the coast in brackish lagoons." "They' re home to the most unlikely Galápagos residents," "Greater Flamingos, chance immigrants from the Caribbean." "There are only about 500 flamingos in Galápagos, limited to this rare habitat." "Along the margins of these mature islands, where it's drier and hotter, the landscape is dominated by giant cactus forest," "offering a perfect watchtower for the islands' top land predator, the Galápagos Hawk." "Something on the shoreline catches its attention." "Small lizards, birds and insects are the normal quarry." "But for a few weeks a year, there's much more on offer." "Marine iguanas prefer to keep to the water's edge, but during the nesting season, females must brave it inland to find soft soil in which to lay their eggs." "But she must go carefully." "The hawk patiently waits to see if she drops her guard." "She's reasonably safe." "Close to her nest burrow." "But stray too far from cover and she's courting trouble." "(HAWK CHIRPING)" "The family has timed its breeding to coincide with this plentiful supply of food." "Both parents take turns to hunt for, and feed their growing chick." "He's only a few weeks old but he's got a healthy appetite." "He can comfortably eat half an iguana a day." "As the Galápagos Islands are carried further and further away from their place of birth, the volcanic hotspot, there's a remarkable progression." "From barren rock and ash-covered deserts, life gets a grip," "creeping inland to mellow and diversify." "But the story doesn't end there." "For every island is destined for a spectacular final flourish." "The oldest of them all, almost 1 00 times older than Fernandina, lies on the south-eastern perimeter of the archipelago." "Española." "Once a much larger volcano, all that remains is a dry, flat scrap of land." "This island is dying." "But it's been carried to a place where the nutrient-rich H umboldt Current gives it a last breath of life." "Its leeward, northern shores have softened through time and they' re a choice hangout for Galápagos sea lions." "A male controls a stretch of coastline, attracting up to 30 females and their young." "(GRU NTING)" "Females give birth to a single pup, nourished on milk rich in protein and fat." "When the pups are about a month old, they join the local crèche." "It looks an easy life." "But for this 500-pound beach master, there's no time to relax." "Even with every ounce of effort, he'll be lucky to rule this stretch of sand for more than three weeks." "This is why." "There are constant challengers." "This time, the beach master wins, leaving his rival battered and scarred." "When the young sea lions are a year or two old, the bay becomes a training ground for social and hunting skills." "These waters are so rich, and the sea lions such effective predators, that it frees up time to enjoy." "Few sea creatures are as playful." "Though the northern side of Española is reasonably sheltered from prevailing winds," "the southern side takes the full brunt of everything the ocean throws at it." "Yet these cliffs are a mecca for seafaring iguanas, and a crucial nesting platform for resident seabirds." "The most majestic of all is a visitor, an ocean wanderer that roams the whole eastern Pacific." "The Waved Albatross is the largest bird in Galápagos, with a seven-foot wingspan." "After six months in the air, first touch down is never that simple." "Virtually the entire world population, some 1 2,000 breeding pairs, nest here on Española." "The male waits for days, sometimes weeks, for the arrival of his partner." "Waved Albatrosses may live for up to 50 years and pair for life." "They re-bond with a mesmerising courtship dance." "The whole colony comes alive with the clack of beaks." "For such huge birds, mating is a gentle affair." "The name, "Waved" Albatross, comes from the delicate pattern of their feathers." "Everything is gambled on a single egg which is incubated by both parents for two months, with each sitting for up to two weeks at a time, sometimes longer." "And the result of such careful and diligent nurture is this." "As the chicks age, their parents' foraging missions take them further and further afield, involving round trips of up to 2,000 miles." "The chicks are fed on pre-digested squid and fish, guzzling nearly half a gallon of oil in one big hit." "Finally, after almost six months, the juveniles and their parents begin to take to the air." "The young albatrosses won't be back to breed for another five or six years." "Their journey is just beginning." "But this island's journey is nearing its end." "Life here outlives the land." "During the last three and a half million years," "Española has travelled over 1 00 miles from its place of birth, the Galápagos hotspot." "Through that time, it's been cooling and contracting, fracturing and sinking." "One day it will end up beneath the waves." "All the islands will eventually follow, carried on the conveyor belt, to meet the same fate." "Countless Galápagos islands have come and gone." "They always have and they always will." "Just as the islands mature through time, so has our understanding of what makes them special." "The first person to set foot on Galápagos prayed only for deliverance from this wretched place." "In the centuries to follow, all who came here to plunder shared his view." "But in time, one man, inspired by the landscape and wildlife, would see things differently, discovering a secret that lay hidden within this island universe." "A secret that would transform not just how we saw these islands, but our whole understanding of life on Earth." "H is name was Charles Darwin." "In the next programme, we travel deeper into the heart of Galápagos and find out why these islands, more than anywhere else, are such a crucible for new life."