0:00:05 > 0:00:11The power of the sun drives the seasons, transforming our planet.
0:00:11 > 0:00:15Vast movements of ocean and air currents
0:00:15 > 0:00:18bring dramatic change throughout the year.
0:00:22 > 0:00:26And in a few special places, these seasonal changes
0:00:26 > 0:00:30create some of the greatest wildlife spectacles on Earth.
0:00:33 > 0:00:36One of the most remarkable transformations
0:00:36 > 0:00:41occurs here in Southern Africa, in the desert lands of the Kalahari.
0:00:43 > 0:00:47Large herds of animals trek for months in search of food and water,
0:00:47 > 0:00:53waiting for an event that will dramatically change their lives.
0:00:53 > 0:00:59For once a year, life-giving water turns an area of unforgiving desert
0:00:59 > 0:01:05into a vast watery paradise known as the Okavango.
0:01:18 > 0:01:21Where and when the Okavango will flood
0:01:21 > 0:01:24determines the fate of millions of animals,
0:01:24 > 0:01:28making this one of nature's truly great events.
0:01:54 > 0:01:58In the heart of southern Africa, the desert lands of the Kalahari
0:01:58 > 0:02:03cover an area of almost 400,000 square miles.
0:02:04 > 0:02:07It's one of driest places on Earth,
0:02:07 > 0:02:13yet miraculously, great herds of grazing animals survive here.
0:02:15 > 0:02:18They lead a nomadic existence,
0:02:18 > 0:02:22trekking huge distances in search of food and water.
0:02:33 > 0:02:36It's the start of the dry season.
0:02:36 > 0:02:38It won't rain for eight months,
0:02:38 > 0:02:42and so life, already hard, is about to get even harder.
0:02:55 > 0:03:00Of all the animals here, perhaps the most resourceful are the elephants.
0:03:03 > 0:03:07Each family is led by an older female, the matriarch,
0:03:07 > 0:03:12and they all rely on her experience to guide them through the desert.
0:03:20 > 0:03:24Her years here have taught this matriarch that, one day,
0:03:24 > 0:03:29hundreds of miles to the west, she will find a lush grassland.
0:03:31 > 0:03:32But, before she will find it,
0:03:32 > 0:03:37her family will have to survive many months in the desert.
0:03:40 > 0:03:44The water that could transform their lives has its origins
0:03:44 > 0:03:49a thousand miles away, in the rain clouds over the highlands of Angola.
0:03:49 > 0:03:52THUNDER
0:04:04 > 0:04:09The rain is so plentiful it has the power to transform a desert.
0:04:12 > 0:04:14It cascades southwards,
0:04:14 > 0:04:17not to the sea, but into the heart of the Kalahari,
0:04:17 > 0:04:23towards a basin shaped like a hand known as the Okavango.
0:04:29 > 0:04:33Here it will fill the swamp that lies at its entrance,
0:04:33 > 0:04:38and only if the rains have been plentiful will water flood out
0:04:38 > 0:04:41onto the arid plains beyond, transforming them
0:04:41 > 0:04:45into the grassland paradise that the herds so badly need.
0:04:53 > 0:04:59Out in the desert, the elephants need to find water every three days.
0:05:00 > 0:05:04Thirsty elephants often race into pools,
0:05:04 > 0:05:08but the matriarch knows that her family must not rush in.
0:05:13 > 0:05:15This pool is stagnant,
0:05:15 > 0:05:19and the elephants have a trick that deals with that.
0:05:25 > 0:05:27Sediment settles to the bottom,
0:05:27 > 0:05:30and the cleaner, fresher water lies on the surface.
0:05:35 > 0:05:37They skim it carefully from the top.
0:05:49 > 0:05:51Then, as gently as elephants can,
0:05:51 > 0:05:56they move forward slowly, trying not to disturb the stagnant layers.
0:06:16 > 0:06:20But precious water like this draws in herds from far and wide.
0:06:27 > 0:06:32In the exuberance of a greeting, all their careful work is undone.
0:06:42 > 0:06:46When bulls are forced together by the need for water,
0:06:46 > 0:06:48tempers can flare.
0:07:23 > 0:07:28At this time of year, food and water can often be far apart.
0:07:31 > 0:07:34And so, now that the little ones are refreshed,
0:07:34 > 0:07:37the family has to head off to find food.
0:07:48 > 0:07:54The distant Okavango plains that they're heading for are still dry,
0:07:54 > 0:07:56and getting even drier.
0:08:02 > 0:08:06Trapped catfish struggle in a shrinking pool.
0:08:19 > 0:08:23And the burning sun is not their only enemy.
0:08:25 > 0:08:27SQUAWKING
0:08:30 > 0:08:35An opportunity like this attracts eagles from many miles away.
0:08:38 > 0:08:43Usually, they dive and snatch fish from the surface of the water,
0:08:43 > 0:08:46but in this drought they won't have to work so hard.
0:08:51 > 0:08:54These are prized catches.
0:09:04 > 0:09:08Marabou storks and jackals muscle in on the leftovers.
0:09:13 > 0:09:15But even with this bounty of fish,
0:09:15 > 0:09:20it's in an eagle's nature to steal a meal rather than catch its own.
0:09:49 > 0:09:54And all this squabbling gives the Marabou a chance...
0:10:03 > 0:10:05Got it!
0:10:08 > 0:10:12Only the return of the flood can save these fish now.
0:10:14 > 0:10:16All around these pools,
0:10:16 > 0:10:20the grass on the Okavango plains continues to wither and die.
0:10:25 > 0:10:28But there's still some nourishment left in the leaves,
0:10:28 > 0:10:33and millions of tiny mouths make the most of what remains.
0:10:33 > 0:10:35INSECT CHATTER
0:10:38 > 0:10:40Termites chop the dead grass
0:10:40 > 0:10:43and drag it underground to feed their colony.
0:10:47 > 0:10:50They play a crucial role,
0:10:50 > 0:10:53helping to return nutrients to these poor soils.
0:10:53 > 0:10:57But now, taking the last precious grass,
0:10:57 > 0:11:00they leave dust and sand in its place.
0:11:08 > 0:11:11With the grazing animals dispersed far and wide,
0:11:11 > 0:11:14it's leaner times for predators here.
0:11:28 > 0:11:33Only a desperate leopard would tackle a porcupine.
0:11:39 > 0:11:42This youngster is about to meet double trouble.
0:11:46 > 0:11:50The only place to get a bite is on their undersides.
0:11:50 > 0:11:54But the porcupines work together to watch each other's backs.
0:12:06 > 0:12:09The leopard will have to flip one over.
0:12:15 > 0:12:21Pin-sharp quills can easily snap off and become embedded in flesh.
0:12:37 > 0:12:41It's a highly effective defence, that can also be turned into attack.
0:12:58 > 0:13:02It's a harsh lesson, but with luck and a bit of healing time,
0:13:02 > 0:13:04there'll be no lasting damage.
0:13:11 > 0:13:15200 miles away, the pulse of life-giving water
0:13:15 > 0:13:20has now reached the swampland at the entrance to the Okavango.
0:13:22 > 0:13:25Here, thick beds of papyrus act like a sponge,
0:13:25 > 0:13:27slowing the water's progress.
0:13:28 > 0:13:30The swamp can take months to fill,
0:13:30 > 0:13:34and only then, if there is enough water,
0:13:34 > 0:13:38can it overflow and rejuvenate the plains on which the herds depend.
0:13:45 > 0:13:47Far to the east,
0:13:47 > 0:13:52the matriarch elephants have led their families to desert woodlands.
0:13:56 > 0:13:59It seems an odd place to come.
0:13:59 > 0:14:04There's no sign of food, and there's little shade for the calves.
0:14:08 > 0:14:11But elephants can do something unusual.
0:14:11 > 0:14:13ELEPHANT TRUMPETS
0:14:15 > 0:14:19They can eat and digest seemingly lifeless branches.
0:14:31 > 0:14:38The youngsters need to learn that dry sticks are nutritious.
0:14:38 > 0:14:41And that there is moisture in the bark.
0:14:45 > 0:14:48But bark won't feed the youngest calves.
0:14:48 > 0:14:52They need to drink 15 litres of milk a day,
0:14:52 > 0:14:56so their mothers desperately need water as well as food.
0:15:00 > 0:15:04Exhaustion has got the better of one young female.
0:15:10 > 0:15:13But she won't get the chance to rest for long.
0:15:13 > 0:15:16The next waterhole could be 30 miles away,
0:15:16 > 0:15:19and the whole herd needs to get moving.
0:15:33 > 0:15:35Back on the Okavango plains,
0:15:35 > 0:15:38the last remnants of grass are going up in smoke.
0:15:46 > 0:15:49It's bad news for the few grazers that remain.
0:16:03 > 0:16:08The few birds collect the escaping insects.
0:16:12 > 0:16:16But fires don't help those who need to eat grass here and now.
0:16:32 > 0:16:36The Okavango plains are at their most desolate.
0:16:36 > 0:16:41Yet out in the desert, the elephant herds are heading towards them.
0:16:48 > 0:16:53The matriarchs guide their families along the maze of trails
0:16:53 > 0:16:54to the next water hole.
0:16:54 > 0:16:56ELEPHANT GROWLS
0:17:02 > 0:17:05And this time, there's no hanging about.
0:17:23 > 0:17:26It soon turns into a mud bath...
0:17:29 > 0:17:32..but elephants have a use for the mud too.
0:17:32 > 0:17:38For mud acts both as a sunscreen and an insect repellent.
0:17:51 > 0:17:55Buffalo have learned to follow the elephant trails to water.
0:18:03 > 0:18:06There is a clear pecking order here.
0:18:07 > 0:18:10Elephants take priority,
0:18:10 > 0:18:13and zebra are the last in the line.
0:18:26 > 0:18:29Even when young bulls have drunk their fill,
0:18:29 > 0:18:32they still torment the buffalo.
0:18:35 > 0:18:37And they definitely know which end to aim for!
0:18:49 > 0:18:53By the time the herds face their final trek across open desert,
0:18:53 > 0:18:55the swamp has filled.
0:18:59 > 0:19:02The channels which lead out onto the parched plains
0:19:02 > 0:19:05get their first welcome trickle of water.
0:19:14 > 0:19:18Amazingly, when the plains are at their driest,
0:19:18 > 0:19:23fresh water from a distant land spills into the parched river beds.
0:19:27 > 0:19:30First it fills the dry channels,
0:19:30 > 0:19:33leaving the baked plains on either side hard and dry.
0:19:52 > 0:19:57All along the route, it finds empty pools to fill.
0:20:00 > 0:20:03And now these pools become magnets for birds,
0:20:03 > 0:20:07which flock here from the surrounding desert lands.
0:20:12 > 0:20:16Red-billed quelea can now collect those grass seeds
0:20:16 > 0:20:18that the termites have missed.
0:20:38 > 0:20:41For most of the year, the quelea are nomadic,
0:20:41 > 0:20:44and it's this freedom to follow the water
0:20:44 > 0:20:49that helps make quelea one of the most numerous birds on earth.
0:21:07 > 0:21:09As the water fills the Okavango,
0:21:09 > 0:21:12animals that have survived in shrinking waterholes
0:21:12 > 0:21:15begin to move in.
0:21:16 > 0:21:19Female hippos gather in the best territories.
0:21:20 > 0:21:24And this male is prepared to fight for one.
0:21:33 > 0:21:36Only a dominant bull will mate with the females,
0:21:36 > 0:21:39and the current chieftain isn't prepared to give way.
0:21:45 > 0:21:47HIPPO GROWLS
0:21:48 > 0:21:50The intimidation begins.
0:22:00 > 0:22:04When neither backs down, there can only be one outcome.
0:22:20 > 0:22:23Fights can go on for hours and can be to the death.
0:22:30 > 0:22:35Forward-pointing tusks can stab right through protective blubber.
0:23:12 > 0:23:17This savage bite to the head brings the contest to an end.
0:23:29 > 0:23:34The incumbent has re-established his right to mate with the females,
0:23:34 > 0:23:37and he wastes no time.
0:23:43 > 0:23:45This is a prime territory,
0:23:45 > 0:23:48and he will face many more challenges
0:23:48 > 0:23:50if he is to continue to hold it.
0:23:58 > 0:24:00The loser is badly injured.
0:24:03 > 0:24:06Hippos can die from infected wounds,
0:24:06 > 0:24:10but this young male is fit, and should survive.
0:24:14 > 0:24:17Oxpeckers are a mixed blessing.
0:24:17 > 0:24:21They keep his wounds clean, but they also keep them open.
0:24:34 > 0:24:38Fresh water continues to pump through the Okavango plains,
0:24:38 > 0:24:40bringing life wherever it flows.
0:24:42 > 0:24:47But out in the Kalahari, water is now almost impossible to find.
0:24:53 > 0:24:56A matriarch has led her family many miles
0:24:56 > 0:24:59only to find the water hole empty.
0:25:05 > 0:25:09This year, the drought is gripping hard.
0:25:12 > 0:25:15Each matriarch encourages her family onward.
0:25:18 > 0:25:20The calves' lives depend on her.
0:25:26 > 0:25:30And with pools so scarce now, even when she finds water,
0:25:30 > 0:25:34they won't be drinking alone.
0:25:41 > 0:25:43At this time of year,
0:25:43 > 0:25:48some lion prides base themselves around water holes,
0:25:48 > 0:25:52and they're always on the lookout for a meal.
0:26:01 > 0:26:07But the elephants' desperate need to drink outweighs the risk.
0:26:12 > 0:26:16The mothers are producing less milk, and the calves are weak.
0:26:22 > 0:26:25The adults try to shield them from watchful eyes.
0:26:28 > 0:26:31It's an uneasy standoff.
0:26:37 > 0:26:40In daylight, the elephants should have nothing to fear.
0:26:50 > 0:26:56The lions creep as close as they dare, as they, too, try to drink.
0:27:08 > 0:27:12One mistake from an elephant, and the lions could attack.
0:27:15 > 0:27:18Big cats keep tired elephants on their toes.
0:27:19 > 0:27:21ELEPHANT TRUMPETS
0:27:26 > 0:27:29While the desert experiences the peak of the drought,
0:27:29 > 0:27:32the meandering network of channels in the Okavango
0:27:32 > 0:27:34is finally brim-full.
0:27:35 > 0:27:38They're ready to overflow.
0:27:42 > 0:27:48Fish gather, ready to ride the flood as a miracle begins to materialise.
0:27:53 > 0:27:59And the barrier of desert sand seems to dissolve in the magical water.
0:28:11 > 0:28:14Under cloudless Kalahari skies,
0:28:14 > 0:28:19fresh sweet water at last begins to bathe the parched plains.
0:28:58 > 0:29:03Millions upon millions of litres surge over the banks.
0:29:08 > 0:29:10This is what the fish have been waiting for.
0:29:14 > 0:29:17New life returns.
0:29:40 > 0:29:44And as the water soaks deep into the sand,
0:29:44 > 0:29:46it stirs dormant animals into life.
0:29:55 > 0:29:58Others are more forcibly evicted.
0:30:02 > 0:30:07It's all fresh food, a banquet ready for the feasting.
0:30:18 > 0:30:20Water birds follow the advancing front,
0:30:20 > 0:30:23making the most of the sudden harvest.
0:30:45 > 0:30:48The plains soon teem with life.
0:30:51 > 0:30:53But not all are here to feed,
0:30:53 > 0:30:56some have come to breed.
0:31:01 > 0:31:03No-one knows where they've come from,
0:31:03 > 0:31:06but within moments of the flood's arrival,
0:31:06 > 0:31:11tens of thousands of dragonflies appear at the water's edge.
0:31:23 > 0:31:28The vivid red male leads his partner in a magical dance,
0:31:28 > 0:31:30guiding her to lay their eggs in the shallows.
0:32:12 > 0:32:14The flood spills ever onwards
0:32:14 > 0:32:19until it finally reaches the outer fringes of the Okavango.
0:32:23 > 0:32:27The catfish, miraculously, still cling to life.
0:32:48 > 0:32:50Within moments,
0:32:50 > 0:32:54the life-giving power of fresh water revitalises them.
0:33:25 > 0:33:29And now, on the plains that appeared so lifeless,
0:33:29 > 0:33:33some of the most beautiful and colourful changes occur.
0:33:37 > 0:33:42Within days, fields of lilies burst into life.
0:33:52 > 0:33:56They provide pollen for the early bees,
0:33:56 > 0:33:59and a hiding place for reed frogs.
0:34:10 > 0:34:14And it's only now that the most crucial gift of the flood,
0:34:14 > 0:34:20the grass that the desert herds need so badly, begins to grow.
0:34:47 > 0:34:52Hippos bulldoze their way towards the sprouting grasslands,
0:34:52 > 0:34:56their paths opening up new arteries that help keep the water flowing.
0:35:04 > 0:35:08In just a few weeks, thousands of square miles
0:35:08 > 0:35:15of dry desert plains are turned into a watery, green grassland.
0:35:18 > 0:35:22The network of hippo paths benefits all kinds of other animals,
0:35:22 > 0:35:26from predatory crocodiles to the grazing herds.
0:35:44 > 0:35:47This fresh grass is what the elephants,
0:35:47 > 0:35:52and indeed all the grazing animals, have been waiting for.
0:35:59 > 0:36:01Their pace quickens.
0:36:03 > 0:36:07For months, they have only known the dry smell of the desert,
0:36:08 > 0:36:13and now they can catch the scent of fresh grass in the wind.
0:36:18 > 0:36:23Red lechwe are the first to take advantage of the young shoots.
0:36:41 > 0:36:43ZEBRA SNORTS
0:37:11 > 0:37:14The lions are no threat here.
0:37:14 > 0:37:19They're not very fast in water and their prey seem to know it.
0:37:23 > 0:37:26Lechwe revel in the safety the flood brings.
0:38:10 > 0:38:14Soon they will be joined by the herds of elephant and buffalo.
0:38:17 > 0:38:20And the lions seem to know they're not far away.
0:38:25 > 0:38:27BABOON SHRIEKS
0:38:27 > 0:38:32Baboons don't enjoy getting their feet wet...
0:38:33 > 0:38:39but the banquet of flowers and juicy snails is just irresistible.
0:38:55 > 0:39:00But they're at their most vulnerable here from lurking crocodiles,
0:39:00 > 0:39:03so they keep an ever watchful eye.
0:39:04 > 0:39:10Babies just cling on tight and hope the water doesn't get too deep.
0:39:14 > 0:39:19At their feet, the flooded plains are now a vast fish nursery,
0:39:19 > 0:39:21teeming with life.
0:39:26 > 0:39:28Predatory fish follow.
0:39:35 > 0:39:38But they too will have to be wary...
0:39:42 > 0:39:47..for the Okavango now puts on one of the finest bird shows
0:39:47 > 0:39:49to be seen anywhere in the world.
0:39:49 > 0:39:51BIRDS TWITTER
0:39:58 > 0:40:01BIRDS CAW
0:40:11 > 0:40:16The rising waters create thousands of tiny islands.
0:40:16 > 0:40:19Safe from predators, surrounded by fish,
0:40:19 > 0:40:23these are the perfect place to raise chicks.
0:40:33 > 0:40:36This is the miracle of the Okavango.
0:40:36 > 0:40:39CHICKS TWITTER
0:40:39 > 0:40:43Once a year, it provides a magical time of plenty
0:40:43 > 0:40:46at the height of the dry season in the middle of a desert.
0:40:57 > 0:41:01Only now, with the grasslands at their most productive,
0:41:01 > 0:41:04do the great herds arrive,
0:41:04 > 0:41:07and they've timed it to perfection.
0:41:09 > 0:41:13The herds grow larger as elephant families and buffalo
0:41:13 > 0:41:16converge from all over the desert.
0:41:23 > 0:41:26But as they all get closer to the flooded grassland,
0:41:26 > 0:41:30there is one final challenge to face.
0:41:47 > 0:41:53Lions have chosen this thick cover to lay their ambushes.
0:41:58 > 0:42:01Their favourite prey is the buffalo.
0:42:06 > 0:42:11Adult buffalo are powerful and can easily trample lions...
0:42:13 > 0:42:20..so the lionesses seek out weaker calves that fall behind the herd.
0:42:24 > 0:42:27BUFFALO MOOS
0:42:27 > 0:42:30A nervous buffalo mother spots their approach...
0:42:31 > 0:42:34..and the herd stampedes.
0:42:35 > 0:42:40One lioness takes a gamble, moving in on a well-protected calf.
0:42:44 > 0:42:47The buffalo close ranks...
0:42:47 > 0:42:51and suddenly the lionesses beat a hasty retreat.
0:42:51 > 0:42:54LIONESSES GROWL
0:43:02 > 0:43:04LIONESSES ROAR
0:43:06 > 0:43:09In the panic, calves are separated from their mothers.
0:43:11 > 0:43:16Amid the confusion, a lioness darts in and grabs one.
0:43:23 > 0:43:26Many buffalo will fall to lions here.
0:43:34 > 0:43:36Lions are opportunists,
0:43:36 > 0:43:41and even an unguarded elephant calf can be vulnerable.
0:43:52 > 0:43:55The elephants are nervous.
0:43:59 > 0:44:02The scent of lion is all around, yet they can't see them.
0:44:07 > 0:44:09The lioness is following them,
0:44:09 > 0:44:12trying to separate the young straggler from the herd.
0:44:14 > 0:44:16ELEPHANT TRUMPETS
0:44:16 > 0:44:19One adolescent fights back, confronting its enemy.
0:44:34 > 0:44:36In the panic, the family stampedes.
0:44:40 > 0:44:42The straggler is taken.
0:44:56 > 0:44:59After months of arduous trekking,
0:44:59 > 0:45:03this elephant family has lost one of its young ones.
0:45:10 > 0:45:14But most of the elephants, at last, have made it through,
0:45:14 > 0:45:17and the great flood awaits.
0:45:19 > 0:45:24Older elephants have been here many times before,
0:45:24 > 0:45:28but the newest calves have never seen so much refreshment.
0:45:46 > 0:45:51At last, they get that first drink of sweet fresh water.
0:46:23 > 0:46:26Thousands of buffalo and zebra
0:46:26 > 0:46:30have also made it to the magical Okavango wetlands.
0:46:45 > 0:46:50Somehow, these remarkable elephants have learned how to find a flood
0:46:50 > 0:46:52from hundreds of miles away
0:46:52 > 0:46:56and to time their arrival just right.
0:47:01 > 0:47:05If it wasn't for this annual gift of precious grass,
0:47:05 > 0:47:11the herds couldn't survive the dry season in the surrounding Kalahari.
0:47:16 > 0:47:20This year, the great flood has lived up to its name.
0:47:41 > 0:47:45The lives of these elephants are dominated by this annual rhythm
0:47:45 > 0:47:52of wet and dry, a seasonal cycle driven by the power of the sun.
0:48:01 > 0:48:06The Okavango River has no great lake to flow into,
0:48:06 > 0:48:09nor does it ever reach the sea.
0:48:09 > 0:48:12Its life-giving waters simply evaporate
0:48:12 > 0:48:15into the great emptiness of the Kalahari sky.
0:48:20 > 0:48:25In a few months, some may fall as rain far to the north,
0:48:25 > 0:48:29and once again become part of this miraculous event in the Okavango
0:48:29 > 0:48:33that is the Great Flood.
0:49:01 > 0:49:04In the making of the Great Flood, the biggest challenge
0:49:04 > 0:49:07for the filming team was to capture the magical moment
0:49:07 > 0:49:11when new floodwater first transformed the desert.
0:49:15 > 0:49:16But to do this
0:49:16 > 0:49:21would mean crossing some of the most challenging terrain in the world,
0:49:21 > 0:49:25pitting themselves against the very water they'd come to film.
0:49:31 > 0:49:34We're right in the heart of the delta now.
0:49:34 > 0:49:36The flood's been in here for a couple of weeks,
0:49:36 > 0:49:38but the real action's happening out west,
0:49:38 > 0:49:42across 20 kilometres of deep swampland,
0:49:42 > 0:49:45and our mission right now is to get this crane rig out there
0:49:45 > 0:49:47to where the action's really happening
0:49:47 > 0:49:50and see if we can get a great new perspective on the flood coming in.
0:49:53 > 0:49:55To achieve this new look,
0:49:55 > 0:49:58the team were using some of the latest camera technology.
0:49:58 > 0:50:03But first they had to find the advancing flood,
0:50:03 > 0:50:07and the only way to do this was from the air.
0:50:07 > 0:50:09PLANE ENGINES ROAR
0:50:11 > 0:50:14Mike has worked here for more than 20 years
0:50:14 > 0:50:18and knows that this will be a race against time.
0:50:20 > 0:50:23The flood was already well advanced
0:50:23 > 0:50:26and wasn't going to wait for a film crew.
0:50:33 > 0:50:34Mike pinpointed the water's edge,
0:50:34 > 0:50:39and on his way back, laid a GPS trail to follow.
0:50:43 > 0:50:47The flight took only 20 minutes, but it would take the ground crew
0:50:47 > 0:50:51at least three days or more to get there.
0:50:52 > 0:50:56And there was no guarantee they'd get through the swamps.
0:51:00 > 0:51:03Are you watching for crocodiles? OK, good.
0:51:07 > 0:51:09Fortunately at this cooler time of year,
0:51:09 > 0:51:15crocodiles are less active and wouldn't pose a serious threat.
0:51:15 > 0:51:18The reason Richard's wading in crocodile-infested waters
0:51:18 > 0:51:22is that we're on this side and we need to be on the other side,
0:51:22 > 0:51:23and he's wading so that we can see
0:51:23 > 0:51:26how deep it is for this vehicle to cross.
0:51:30 > 0:51:33These trucks are specially adapted
0:51:33 > 0:51:35to cope with such extreme conditions.
0:51:37 > 0:51:41They can drive in water up to seven feet deep...
0:51:45 > 0:51:48..and cross all but the boggiest terrain.
0:51:52 > 0:51:57Unfortunately, not all the equipment fared so well.
0:51:57 > 0:52:00I don't think this is going to be much use to anyone.
0:52:02 > 0:52:07But even the vehicles weren't immune to such punishing use.
0:52:07 > 0:52:12Problems...always arise when you least expect it.
0:52:16 > 0:52:19Kubu, this truck, who's our swamp truck,
0:52:19 > 0:52:22has decided...to...
0:52:22 > 0:52:24give us problems again.
0:52:24 > 0:52:26The diff has basically collapsed on us,
0:52:26 > 0:52:29we're running out of daylight at the moment,
0:52:29 > 0:52:32so we've gotta sort this out.
0:52:32 > 0:52:35HAMMERING
0:52:35 > 0:52:38To film here, you have to be a jack-of-all-trades -
0:52:38 > 0:52:42a film-maker, tracker and a mechanic.
0:52:44 > 0:52:47Despite some on-the-spot bush repairs,
0:52:47 > 0:52:51a replacement part had to be ordered in.
0:52:51 > 0:52:53Hello?
0:52:55 > 0:52:56Ow!
0:52:57 > 0:53:00It's going to be a long night in the bush.
0:53:01 > 0:53:04All the crew could do now was wait.
0:53:11 > 0:53:14With the nearest garage over two days away by truck,
0:53:14 > 0:53:18there was only one way the new part could be delivered.
0:53:27 > 0:53:29Now the crew could get back on the road
0:53:29 > 0:53:33and start making up for lost time.
0:53:39 > 0:53:42But they would have to choose their route carefully.
0:53:43 > 0:53:46The best way to pick a path is where the elephants cross
0:53:46 > 0:53:50because they've got regular routes that are the shallowest places,
0:53:50 > 0:53:53but often where they've crossed it's churned up the mud,
0:53:53 > 0:53:55so we try and stay slightly off there.
0:53:55 > 0:53:58But once you get into the middle of that, it's just hope like hell
0:53:58 > 0:54:01and keep going, because it's probably deep
0:54:01 > 0:54:03and very soggy in the middle.
0:54:15 > 0:54:17OK, this is getting a bit silly.
0:54:17 > 0:54:19We're officially stuck.
0:54:19 > 0:54:23Mike's concerns proved well-founded.
0:54:23 > 0:54:26The shallower route was simply too boggy.
0:54:28 > 0:54:30That left the crew with no choice
0:54:30 > 0:54:35but to tackle the longer, deeper route and hold their nerve.
0:54:48 > 0:54:50Coming in the windows!
0:54:50 > 0:54:52Whoa! Now I'm getting wet.
0:55:02 > 0:55:05Whoa, water's coming in!
0:55:13 > 0:55:15It's a little damp in here now.
0:55:40 > 0:55:45That was interesting, but we made it across the swamp!
0:55:45 > 0:55:47Success!
0:55:47 > 0:55:51Mike and the team had finally got ahead of the flood.
0:55:55 > 0:55:58They were now in a truly privileged position,
0:55:58 > 0:56:01ready to capture the amazing transformation
0:56:01 > 0:56:04that was about to unfold.
0:56:07 > 0:56:10OK, so drop the camera over the middle of the pool there.
0:56:13 > 0:56:16The flood had arrived.
0:56:17 > 0:56:18Here it comes.
0:56:33 > 0:56:36Three...two...one...
0:56:42 > 0:56:47Using cranes and specially-developed close-up camera systems,
0:56:47 > 0:56:49the Nature's Great Events team
0:56:49 > 0:56:54could finally set about bringing the advancing flood to life.
0:56:55 > 0:56:57This is one of those magical transformation moments,
0:56:57 > 0:57:00where you've got a landscape which is asleep that way,
0:57:00 > 0:57:03and you've got the flood, which is like the catalyst
0:57:03 > 0:57:05which is going to bring that landscape to life
0:57:05 > 0:57:08and it's happening right in front of us, which is amazing.
0:57:08 > 0:57:14And we've got a bit of macro kit that exists nowhere else in the world,
0:57:14 > 0:57:18and we're able to follow it at the really tiniest level.
0:57:28 > 0:57:31This was the Great Flood,
0:57:31 > 0:57:35but filmed on a scale that had never been seen before.
0:57:51 > 0:57:53Sounds like my hole is filling up.
0:57:53 > 0:57:57I'm going to get wet, Rich. I'm going to drown in three inches of water.
0:58:03 > 0:58:07Each year, the magical flood rewards Mike with something new.
0:58:07 > 0:58:13Despite years of filming here, he had never seen so many dragonflies.
0:58:18 > 0:58:21It's amazing, though, isn't it? Have you ever watched this happen before?
0:58:21 > 0:58:26It is amazing. I mean, you think this is going on all over the delta,
0:58:26 > 0:58:28miles and miles and miles of water
0:58:28 > 0:58:31just spreading everywhere at this rate.
0:58:31 > 0:58:32Incredible.
0:58:32 > 0:58:38And the team had managed to capture just a tiny part of it,
0:58:38 > 0:58:43revealing in intimate detail the character of the Great Flood.
0:58:50 > 0:58:53Subtitles by Red Bee Media Ltd
0:58:53 > 0:58:56E-mail subtitling@bbc.co.uk