0:00:09 > 0:00:14Let's face it, our world is downright weird.
0:00:14 > 0:00:17Oh, my!
0:00:17 > 0:00:21Crawling with creatures you've never heard of.
0:00:21 > 0:00:24I can't believe that's a living thing.
0:00:24 > 0:00:25Full of the unexpected.
0:00:27 > 0:00:31Like freak weather exploding out of the blue.
0:00:31 > 0:00:33I thought I was going to die.
0:00:33 > 0:00:36And rocks that spontaneously combust.
0:00:36 > 0:00:38I thought it was dynamite going off.
0:00:39 > 0:00:42And the unexplained.
0:00:42 > 0:00:46An unborn twin, discovered inside a brain.
0:00:46 > 0:00:50There was multiple hair follicles, bone and teeth.
0:00:54 > 0:00:59- We've scoured the globe to bring you the very weirdest stories.- Ah!
0:01:02 > 0:01:03I could feel this intense pain,
0:01:03 > 0:01:07as if you were being stabbed by hundreds of syringes.
0:01:12 > 0:01:16In this series, we're going to examine the evidence,
0:01:16 > 0:01:19test the science and unravel the mysteries.
0:01:19 > 0:01:24We're going to discover what in the weird world is going on.
0:01:34 > 0:01:35In this episode,
0:01:35 > 0:01:40we uncover the secrets behind some of the natural world's weirdest events.
0:01:41 > 0:01:46How did this woman find herself inside a meteorological monster?
0:01:51 > 0:01:56What creates a wonderland where flowers bloom underwater?
0:01:57 > 0:02:01How do you extinguish fire with an invisible force?
0:02:03 > 0:02:07And just why has this rat developed a death wish?
0:02:09 > 0:02:12But our first strange story comes to us
0:02:12 > 0:02:15via the internet, all the way from Thailand,
0:02:15 > 0:02:20where a familiar creature was caught doing something unbelievably bizarre.
0:02:23 > 0:02:30Have a look at this. Posted in May 2015, filmed during a fishing trip.
0:02:32 > 0:02:34Looks pretty ordinary, doesn't it?
0:02:34 > 0:02:38Your run-of-the-mill, bog-standard worm.
0:02:38 > 0:02:40Oh, no. Are you ready?
0:02:44 > 0:02:47I told you. Do you want to see it again? Of course you do.
0:02:52 > 0:02:56Hand on heart, this is real. There are no special effects here.
0:02:57 > 0:02:59Look, and just to prove it,
0:02:59 > 0:03:03here's another example found in a fisherman's net in Taiwan.
0:03:09 > 0:03:13These bizarre creatures are called ribbon worms.
0:03:15 > 0:03:18And although there are over 1000 species,
0:03:18 > 0:03:20most of them live in the ocean.
0:03:23 > 0:03:28So, you're unlikely to cross paths with these deep sea
0:03:28 > 0:03:34monstrosities, which is a relief, I suppose, unless, of course,
0:03:34 > 0:03:37you are a scientist obsessed with these weird worms.
0:03:39 > 0:03:41Ribbon worms are incredible animals.
0:03:45 > 0:03:48They really are a unique set of worms.
0:03:50 > 0:03:52You don't say.
0:03:52 > 0:03:54Oh, my goodness.
0:03:54 > 0:03:57Now, it's pretty obvious what sets these worms apart.
0:03:59 > 0:04:03That thing spewing from their bodies is actually a kind of tongue
0:04:03 > 0:04:04called a proboscis.
0:04:05 > 0:04:10It's a crucial appendage, because ribbon worms are a world
0:04:10 > 0:04:12away from the earth eaters we're familiar with.
0:04:15 > 0:04:19Oh, no, they have an appetite for something more substantial.
0:04:24 > 0:04:26Ribbon worms are predators.
0:04:26 > 0:04:29They are the carnivores around in the worm world.
0:04:35 > 0:04:38And what they'll do, is they'll send out this proboscis,
0:04:38 > 0:04:40sense that it's something that they want to eat.
0:04:42 > 0:04:46Then, game over.
0:04:52 > 0:04:56And the biology behind this alarming appendage is very clever indeed.
0:05:00 > 0:05:04The proboscis usually stays in a sack on top of the worm's gut,
0:05:04 > 0:05:07but once the worm senses prey approaching,
0:05:07 > 0:05:11its muscles contract quickly, forcing fluid into the sac
0:05:11 > 0:05:14and shooting it out through a hole in the worm's head.
0:05:18 > 0:05:24Imagine you've got a rubber glove inside your face which you can
0:05:24 > 0:05:27blow into, so that it forces outwards.
0:05:30 > 0:05:35That you can then use to grab whatever is on offer for your lunch,
0:05:35 > 0:05:39before you drop it into your stomach and eat it.
0:05:39 > 0:05:40It's genius.
0:05:43 > 0:05:47And if being able to jettison your innards towards a target
0:05:47 > 0:05:54wasn't spectacular enough, some worms have even customised their appendage.
0:05:54 > 0:05:58Sometimes, these proboscis have little stylets on,
0:05:58 > 0:06:01so hooks that they stab into their prey.
0:06:01 > 0:06:05Some will also produce mucus which then can stun their prey.
0:06:10 > 0:06:14And our friend from the first video is even more extraordinary.
0:06:14 > 0:06:19Only one of two ribbon worms with a branching proboscis that most
0:06:19 > 0:06:23scientists have only ever seen in textbooks.
0:06:23 > 0:06:28It's absolutely fantastic and it's absolutely very weird.
0:06:28 > 0:06:32I'd read about it before, but I have never actually seen any
0:06:32 > 0:06:33footage of it.
0:06:35 > 0:06:37Consider it our gift to you, Emma.
0:06:41 > 0:06:46OK, I can see that regurgitating your insides to grab your next meal
0:06:46 > 0:06:48might not be everyone's cup of tea,
0:06:48 > 0:06:52but our next contender has got an altogether more refined technique.
0:06:56 > 0:07:00Spiders. I suppose you could argue they're pretty weird.
0:07:02 > 0:07:05They're certainly a love them or hate them kind of animal.
0:07:06 > 0:07:08I'm firmly with team spider, of course.
0:07:11 > 0:07:14But I think we can all appreciate that they're very clever
0:07:14 > 0:07:16little creatures.
0:07:22 > 0:07:23They slowly build a web...
0:07:27 > 0:07:30..wait for a fly or another insect to get caught...
0:07:34 > 0:07:37..and then move in for a meal, right?
0:07:39 > 0:07:43Well, not quite.
0:07:44 > 0:07:48Many spiders spin webs which incorporate a type of silk
0:07:48 > 0:07:52which is sticky, but it's not only sticky.
0:07:52 > 0:07:56It's also statically charged, so that the web
0:07:56 > 0:08:00and the prey are drawn inextricably together.
0:08:08 > 0:08:14Can you see the web moving towards the fly?
0:08:17 > 0:08:21It's only a few millimetres, but it's just enough to make
0:08:21 > 0:08:25the difference between snaring a meal and going hungry.
0:08:30 > 0:08:35It's a fantastic trick that thousands of species put to good use.
0:08:40 > 0:08:44But deep in the Peruvian jungle, there's one spider who's refused
0:08:44 > 0:08:46to settle for the norm.
0:08:54 > 0:08:57Now, he might not look like much, but just watch this.
0:09:00 > 0:09:03Captured on film for the first time,
0:09:03 > 0:09:08this tiny spider has designed a projectile web.
0:09:14 > 0:09:16And why has he gone to such extraordinary lengths?
0:09:17 > 0:09:21Well, it's all a matter of expectation.
0:09:27 > 0:09:29You see, this arachnid might be diminutive,
0:09:29 > 0:09:32but it has its sights set very high.
0:09:36 > 0:09:39Flies... Nah!
0:09:40 > 0:09:42Midges... Yuck.
0:09:44 > 0:09:50This spider is only interested in fat, juicy mosquitoes.
0:09:52 > 0:09:53Which is a bit of a problem.
0:09:55 > 0:09:58Mosquitoes, compared to a lot of flying insects,
0:09:58 > 0:10:02they fly quite slowly and are quite deliberate in their movements.
0:10:05 > 0:10:07They also fly with their limbs outstretched.
0:10:07 > 0:10:10It's difficult for them to become trapped in a web.
0:10:10 > 0:10:14So, if they spot a web or feel it with their outstretched legs,
0:10:14 > 0:10:18they can change direction quickly and this allows them
0:10:18 > 0:10:20to avoid the deadliest of traps.
0:10:22 > 0:10:25So, if you're spider with a hankering for a mossie,
0:10:25 > 0:10:27what do you do?
0:10:30 > 0:10:34The spider draws a strand of silk from the centre of its web,
0:10:34 > 0:10:39stretching the whole silky trap into a cone shape, which it then
0:10:39 > 0:10:44catapults with itself attached, towards flying insect prey.
0:10:50 > 0:10:52That's why it's called the slingshot spider.
0:10:57 > 0:11:02The slingshot ratchets back and then fires...
0:11:05 > 0:11:09..colliding with prey before it's had a chance to change its course.
0:11:11 > 0:11:16It's a masterful piece of engineering that makes this spider
0:11:16 > 0:11:17truly deadly...
0:11:18 > 0:11:21..if you're really, really small.
0:11:25 > 0:11:28Now, these spiders are just a few millimetres long,
0:11:28 > 0:11:31so they pose no threat at all to humans, but there is another
0:11:31 > 0:11:36creature that has a far more sinister way of reaching its next victim
0:11:36 > 0:11:39and it's something that we should be truly terrified of.
0:11:42 > 0:11:44Have a look at this.
0:11:49 > 0:11:52A rat chasing a cat.
0:11:54 > 0:11:57Just look at that. Go on, get him!
0:11:59 > 0:12:04This behaviour defies all the rules of nature.
0:12:04 > 0:12:07And it's not a one-off case.
0:12:09 > 0:12:14But this is not a new species of uber-aggressive fighting rodent.
0:12:14 > 0:12:16These rats weren't born with a death wish.
0:12:18 > 0:12:22No, scientists think that this bizarre behaviour might be
0:12:22 > 0:12:27brought about from a run-in with something altogether stranger.
0:12:33 > 0:12:36It's quite possible that these rodents aren't
0:12:36 > 0:12:38acting in their right minds.
0:12:38 > 0:12:41They've been hijacked.
0:12:42 > 0:12:44Hijacked by a parasite.
0:12:45 > 0:12:47Toxoplasma gondii,
0:12:47 > 0:12:52a tiny single cell organism that lives in the rodent's brain.
0:12:54 > 0:12:56Here, it meddles with the neurones
0:12:56 > 0:12:59to render the rat completely fearless.
0:13:01 > 0:13:02But why?
0:13:04 > 0:13:08What possible benefit could it be to the parasite to give the rat
0:13:08 > 0:13:09a death wish?
0:13:13 > 0:13:16Well, here's the really weird thing.
0:13:17 > 0:13:21This parasite doesn't actually like rats very much.
0:13:22 > 0:13:25They're purely a means to an end.
0:13:25 > 0:13:30You see, the ultimate aim for toxoplasma, is to get into a cat.
0:13:30 > 0:13:34What is unique about this parasite, is that it can only reproduce,
0:13:34 > 0:13:37it can only sexually reproduce inside the gut of a cat.
0:13:40 > 0:13:43What it needs to do its life cycle, its evolutionary pressure,
0:13:43 > 0:13:47its need, is to get from one cat to another cat and the question is,
0:13:47 > 0:13:51how does a tiny parasite with no legs, no means of moving
0:13:51 > 0:13:54on its own, how does it get all the way from one cat to another cat?
0:13:57 > 0:14:04Mind control. Toxoplasma makes rats its rodent slaves.
0:14:08 > 0:14:10Here's how it works.
0:14:10 > 0:14:15Toxoplasmosis offspring exit the cat in its faeces.
0:14:15 > 0:14:18The rat or mouse then eats those faeces.
0:14:18 > 0:14:20Once embedded in the rodent's brain,
0:14:20 > 0:14:25the parasite does its thing, significantly lowering the rat's
0:14:25 > 0:14:29inhibitions, making it less cautious and more likely to get eaten.
0:14:30 > 0:14:34Et voila. The life cycle is complete.
0:14:37 > 0:14:42Toxoplasma is a very focused little organism,
0:14:42 > 0:14:44going to extraordinary lengths to make sure
0:14:44 > 0:14:47that this cycle is fulfilled.
0:14:52 > 0:14:57The parasite doesn't only make rats less afraid of cats,
0:14:57 > 0:14:58it does something much weirder.
0:14:59 > 0:15:03We find that in the brains of these animals that are infected
0:15:03 > 0:15:07with the parasite, it looks a little bit like these
0:15:07 > 0:15:09animals are actually sexually attracted
0:15:09 > 0:15:11to the smell of the cat urine.
0:15:13 > 0:15:18Infected rodents aroused by the aroma are enticed into feline
0:15:18 > 0:15:22hang-outs and then eaten.
0:15:24 > 0:15:27The cats are kind of like love hotels for the parasite
0:15:27 > 0:15:30and the rats and the mice are taxis that take them
0:15:30 > 0:15:32in between each individual love hotel.
0:15:34 > 0:15:37Quite a thought. And that's not the end of it.
0:15:39 > 0:15:45The toxoplasma's tale is about to get even darker because,
0:15:45 > 0:15:50and I hate to tell you this, the parasite can infect us too.
0:15:53 > 0:15:55Here's the real shocker.
0:15:55 > 0:15:58Research suggests that this parasite could be lying
0:15:58 > 0:16:02dormant in the brains of one third of us.
0:16:02 > 0:16:03It's truly terrifying.
0:16:08 > 0:16:12Of course, toxoplasma doesn't want to be inside us. We're a dead end.
0:16:15 > 0:16:19It lives trapped inside our brains and what it might be
0:16:19 > 0:16:23doing in there, is, of course, serious cause for concern.
0:16:25 > 0:16:29The big neurobiological question that we want to answer is, if it's
0:16:29 > 0:16:33changing the behaviour of rats and mice, what is it doing to people?
0:16:35 > 0:16:38Well, toxoplasmosis won't have us sniffing out cat urine,
0:16:38 > 0:16:42but studies show that it might be having some very serious
0:16:42 > 0:16:45and very disturbing effects on our mental health.
0:16:47 > 0:16:50Around the world, studies have shown that people with schizophrenia
0:16:50 > 0:16:52have high rates of this parasite.
0:16:54 > 0:16:59Toxoplasmosis is able to alter the way the rat's brain functions.
0:16:59 > 0:17:04When this parasite gets into people, maybe it's doing the same thing.
0:17:04 > 0:17:08Maybe you can have chronic effects on something like mental illness.
0:17:10 > 0:17:15If Patrick can find a link between the parasite and our behaviour,
0:17:15 > 0:17:18then it would change the way we look at mental illness and,
0:17:18 > 0:17:21of course, potentially help find a treatment.
0:17:31 > 0:17:36And just before you lock the cat flap for good, let me reassure you.
0:17:36 > 0:17:40You're most likely to get toxoplasmosis through eating
0:17:40 > 0:17:41raw meat.
0:17:42 > 0:17:48Fertilisers can contain a fair bit of cat faeces, so when the parasite
0:17:48 > 0:17:53gets into the crops, it gets into the cows and then it gets into us.
0:17:54 > 0:17:57Cook your food well, keep your hands washed
0:17:57 > 0:18:01and then you can cuddle your cat free of fear.
0:18:04 > 0:18:10So, toxoplasmosis, the Black Death, Weil's disease, salmonella,
0:18:10 > 0:18:13oh, I don't know.
0:18:13 > 0:18:15The poor old rat really does have a bad reputation,
0:18:15 > 0:18:20which very much upsets me, because I'm a great fan of the rat and that's
0:18:20 > 0:18:25why I'm really pleased that a small group of people are doing everything
0:18:25 > 0:18:29they can to raise its reputation from the mud of human loathing.
0:18:33 > 0:18:37In East Africa, there's one species that is challenging
0:18:37 > 0:18:39the rodent's stereotype.
0:18:43 > 0:18:45The giant African pouched rat.
0:18:47 > 0:18:51This is the new hero of the rodent world.
0:18:52 > 0:18:58Not pests, but highly trained life-saving specialists.
0:19:02 > 0:19:04In the foothills of Tanzania,
0:19:04 > 0:19:08an army of these giant rodents have been trained to save human lives...
0:19:09 > 0:19:13..with just a clicker and a tasty treat.
0:19:18 > 0:19:21They're not strong enough to drag you from a burning building.
0:19:21 > 0:19:23That would be daft.
0:19:23 > 0:19:27But they are just the right size to pull off an astonishing
0:19:27 > 0:19:29feat of bravery.
0:19:29 > 0:19:32Something so clever,
0:19:32 > 0:19:35that you'll never look at a rat in the same way again.
0:19:37 > 0:19:40But first, we need some context.
0:19:44 > 0:19:49Tanzania's neighbour, Mozambique, has had a troubled past.
0:19:49 > 0:19:54Years of civil war have left their mark and nearly 20 years after
0:19:54 > 0:19:58a ceasefire, peaceful fields still claim lives.
0:20:03 > 0:20:08More than 100 million land mines still litter the ground worldwide.
0:20:08 > 0:20:13And they kill more than 4,000 people a year.
0:20:13 > 0:20:17So clearing land mines safely is a pressing concern.
0:20:17 > 0:20:20But how do you do it without the loss of even more lives?
0:20:23 > 0:20:25Well, here is an extraordinary solution.
0:20:28 > 0:20:30A giant, pouched, bomb squad.
0:20:33 > 0:20:35It's not as ridiculous as it sounds.
0:20:38 > 0:20:42Rats have a sense of smell which rivals dogs and, in fact, they can
0:20:42 > 0:20:48smell an infinitesimally small amount of TNT from a metre away or even
0:20:48 > 0:20:51when it's buried deep underground.
0:21:03 > 0:21:06Sniffing out a land mine is a breeze for an African rat.
0:21:08 > 0:21:12But a dangerous job needs serious training.
0:21:13 > 0:21:15Which is easier than you might imagine.
0:21:15 > 0:21:20Because rats are incredibly intelligent animals.
0:21:20 > 0:21:24And if there's one thing they'll do anything for, it's a banana.
0:21:26 > 0:21:30During a nine-month boot camp the rats are taught to
0:21:30 > 0:21:35move along a piece of rope, sniffing for teabags stuffed with TNT.
0:21:35 > 0:21:37They scratch to mark the spot
0:21:37 > 0:21:40and then come running back to the sound of a clicker.
0:21:40 > 0:21:44Mmm, banana!
0:21:44 > 0:21:46Looks like this rat has passed the test.
0:21:53 > 0:21:59Now fully trained, the bomb squad's job becomes deadly serious.
0:22:06 > 0:22:07No more teabags.
0:22:09 > 0:22:12These rats are now searching for real land mines.
0:22:15 > 0:22:18Mines that are designed to activate under foot.
0:22:21 > 0:22:24But these rats haven't gone through all of that training,
0:22:24 > 0:22:28all of those kilos of bananas, just to sacrifice themselves.
0:22:31 > 0:22:36You see, not only are these fantastic rats clever, with a wonderful
0:22:36 > 0:22:39sense of smell, they're also light.
0:22:40 > 0:22:42Just over a kilogram.
0:22:42 > 0:22:46Small enough to go undetected by any mines below.
0:22:52 > 0:22:54And look, he's found the mine.
0:22:55 > 0:22:57Superb!
0:22:57 > 0:22:59Now the disposal team can go to work.
0:23:16 > 0:23:21In just 20 minutes, the rats can cover the same amount of land that
0:23:21 > 0:23:25humans would take five days to search.
0:23:25 > 0:23:30And so far the bomb squad have cleared over 13,000 mines.
0:23:31 > 0:23:35Giving more than 11 million square metres back to the farmers.
0:23:38 > 0:23:41The heroic African pouched rat.
0:23:41 > 0:23:46Making the fields of Mozambique safe, one banana at a time.
0:23:51 > 0:23:55Yes, finally the rat's reputation is on the rise.
0:23:55 > 0:23:57Vive le rat!
0:23:59 > 0:24:04So, an unassuming worm might be concealing a weapon.
0:24:07 > 0:24:11And a tiny spider could be packing a slingshot.
0:24:14 > 0:24:19Invincible rodents are really being controlled by a parasite
0:24:19 > 0:24:25and creatures that we all once thought were pests are now heroes.
0:24:25 > 0:24:27Come on, give that rat a medal.
0:24:31 > 0:24:36For our next journey we're going from a watery wonderland to a stony
0:24:36 > 0:24:38relative with a soft heart.
0:24:38 > 0:24:41And it all starts in the mountains of Austria.
0:24:45 > 0:24:51Dotted with quaint villages, flower-strewn meadows...
0:24:51 > 0:24:52COW MOOS
0:24:54 > 0:24:58..and home to the strangest lake on the planet.
0:25:02 > 0:25:06Every year hundreds of people come from all around the world to
0:25:06 > 0:25:11visit the Emerald Lake near the town of Tragoess.
0:25:11 > 0:25:14But not to picnic by its picture-perfect shores.
0:25:15 > 0:25:20For just two weeks of the year, it entices a different type of tourist.
0:25:22 > 0:25:28Drawn to Tragoess by a secret that lies under the surface.
0:25:47 > 0:25:51You see, something very strange happens at Tragoess.
0:25:57 > 0:26:01And Marc makes a yearly pilgrimage to capture it on camera.
0:26:24 > 0:26:26Bridges...
0:26:28 > 0:26:29..flowers...
0:26:30 > 0:26:32..pathways...
0:26:33 > 0:26:34..benches...
0:26:46 > 0:26:49It's beautiful but totally bizarre.
0:26:52 > 0:26:57I mean, how is it possible that a place exists where fish swim
0:26:57 > 0:27:00through grass and flowers bloom underwater?
0:27:07 > 0:27:10These aren't sub-aquatic species.
0:27:10 > 0:27:15And there hasn't been some sort of natural disaster at Tragoess.
0:27:15 > 0:27:18In fact, the Emerald Lake is only part of the story
0:27:18 > 0:27:22because for much of the year the place looks entirely different.
0:27:26 > 0:27:29For several months the valley lies under a covering of snow.
0:27:33 > 0:27:36You're more likely to see snow bums than divers.
0:27:39 > 0:27:43But as the spring arrives the snow melts.
0:27:45 > 0:27:50Revealing a shallow lake and some very familiar looking landmarks.
0:27:55 > 0:28:00'Pretty? Well, yes. Strange, no.
0:28:00 > 0:28:03'Where is our watery wonderland?
0:28:05 > 0:28:07'Well, stick with me.'
0:28:13 > 0:28:17In early spring, Lake Tragoess is just one metre deep.
0:28:19 > 0:28:21It's a pond, really.
0:28:22 > 0:28:23Diving would be tricky.
0:28:25 > 0:28:31But, as all the melt-water rushes down from the mountains it
0:28:31 > 0:28:32disappears underground.
0:28:34 > 0:28:38Raising the water table under the lake so dramatically...
0:28:40 > 0:28:41..that it begins to fill.
0:28:49 > 0:28:56Until, for two very surreal weeks of the year, the spring growth
0:28:56 > 0:28:58finds itself submerged...
0:28:59 > 0:29:00..ten metres deep.
0:29:20 > 0:29:22An underwater wonderland...
0:29:23 > 0:29:25..created by the seasons.
0:29:29 > 0:29:32Must be pretty confusing to be a fish there. One minute you're
0:29:32 > 0:29:36swimming around in a puddle, the next minute you're in a veritable ocean.
0:29:36 > 0:29:42But there is one species for which the world very rarely changes.
0:29:47 > 0:29:49The Atacama Desert in Chile.
0:29:51 > 0:29:54A hostile moonscape in which temperatures can vary by up
0:29:54 > 0:29:56to 20 Celsius in a day.
0:29:58 > 0:30:01And rain doesn't come for years at a time.
0:30:04 > 0:30:05Not much survives out here.
0:30:07 > 0:30:09Well, except for these.
0:30:13 > 0:30:17Huge bright green blobs melting into the desert.
0:30:22 > 0:30:26Despite their bizarre looks, these blobs had gone under
0:30:26 > 0:30:27the public radar...
0:30:29 > 0:30:34..until 2010 when a photographer with a peculiar interest spotted
0:30:34 > 0:30:36a picture online.
0:30:37 > 0:30:40They truly look alien. They are so strange looking.
0:30:43 > 0:30:46I was definitely intrigued. I could tell right away
0:30:46 > 0:30:48they were going to be very photogenic.
0:30:56 > 0:31:00Inspired by these green globules Rachel embarked upon
0:31:00 > 0:31:04a 10,000km journey to photograph them.
0:31:04 > 0:31:10We headed up into some very high elevations and some extremely arid
0:31:10 > 0:31:14conditions, so parts of the Atacama are known as absolute desert.
0:31:15 > 0:31:20And here, amongst the llamas, Rachael found what she was looking for.
0:31:20 > 0:31:25The first time I saw them they were visually stunning.
0:31:28 > 0:31:29Stunning?
0:31:29 > 0:31:32I suppose so, if pea-coloured pillows are your sort of thing.
0:31:32 > 0:31:35But it certainly got Rachael clicking.
0:31:35 > 0:31:39Some are bulbous, some are these very large, expansive mats.
0:31:41 > 0:31:44They look like they might be soft to the touch like moss would be,
0:31:44 > 0:31:47but they're not. They're a little prickly.
0:31:49 > 0:31:53OK, so what on earth are these spiky, bulbous, matted mounds?
0:31:59 > 0:32:02These bizarre desert sponges may look alien, but they're not.
0:32:02 > 0:32:04They're very much of this world.
0:32:04 > 0:32:06And their closest living relative?
0:32:07 > 0:32:10The humble carrot. Yes.
0:32:10 > 0:32:12The carrot.
0:32:12 > 0:32:14No really, I'm not joking, the carrot.
0:32:16 > 0:32:20Yes, look closely and these blobs reveal themselves as plants.
0:32:20 > 0:32:24Millions of tiny flowering heads called yareta.
0:32:25 > 0:32:30One of the Apiaceae family, alongside carrots, parsley and fennel.
0:32:33 > 0:32:36But don't let their earthly origins or commonplace cousins
0:32:36 > 0:32:37disappoint you.
0:32:38 > 0:32:43Remember I said Rachael had a peculiar artistic interest?
0:32:43 > 0:32:48She didn't travel all that way just to photograph any old flower.
0:32:48 > 0:32:53The yareta was on her photographic hitlist for one very strange reason.
0:32:54 > 0:32:57I spent about ten years working on a project called
0:32:57 > 0:33:00The Oldest Living Things In The World.
0:33:00 > 0:33:05Rachael had been searching for the most ancient plants on our planet.
0:33:05 > 0:33:08When I heard about the yareta it was not only that it was
0:33:08 > 0:33:12an unusual plant, it also happens to be old.
0:33:12 > 0:33:16I saw a whole range of ages from some babies up
0:33:16 > 0:33:19until probably around 3,000 years old.
0:33:20 > 0:33:213,000 years old.
0:33:23 > 0:33:27That means this yareta germinated at the start of the Iron Age.
0:33:30 > 0:33:33Growing just one centimetre every year since.
0:33:35 > 0:33:37In a complete no-man's land.
0:33:43 > 0:33:47If you're a plant, surviving in an arid desert
0:33:47 > 0:33:50environment like this is actually pretty difficult.
0:33:50 > 0:33:52Take a look around.
0:33:52 > 0:33:54It may appear that there are lots of cacti here,
0:33:54 > 0:33:58lots of drought-resistant species, but then look again.
0:33:58 > 0:34:01In fact, there are very few different types of plant here.
0:34:03 > 0:34:06'Cacti are one of the few species that thrive in the heat.
0:34:07 > 0:34:12'Living for up to 180 years, which is impressive
0:34:12 > 0:34:16'but nothing on our green blobs.'
0:34:16 > 0:34:20So how does the yareta manage to survive in such a hostile
0:34:20 > 0:34:22environment for so long?
0:34:23 > 0:34:28It turns out that this other-worldly blob has a secret super power.
0:34:29 > 0:34:33And a clue? Well, it's in the yereta's looks.
0:34:35 > 0:34:40That blob shape reduces the plant's surface area.
0:34:40 > 0:34:44And the tiny heads packed tightly together protect against
0:34:44 > 0:34:47the worst of the weather.
0:34:47 > 0:34:48And under those green heads,
0:34:48 > 0:34:55the remnants of 3,000 years of growth form a cushion, storing water
0:34:55 > 0:34:58and helping the plant to regulate its temperature.
0:34:58 > 0:35:02It's a pretty humbling experience to stand in front of these
0:35:02 > 0:35:06organisms and think about how much they've witnessed
0:35:06 > 0:35:07and weathered and survived.
0:35:09 > 0:35:12The yareta is a super weird, super survivor.
0:35:17 > 0:35:203,000 years - puts a lifespan of a carrot to shame.
0:35:20 > 0:35:24And it's strange to think that these green blobs are related to
0:35:24 > 0:35:26a vegetable we eat.
0:35:26 > 0:35:28But then I suppose I'm always surprised
0:35:28 > 0:35:32by what people are prepared to put in their mouths.
0:35:38 > 0:35:42For our next weird event we're staying in Chile
0:35:42 > 0:35:45but moving on to a very different habitat.
0:35:46 > 0:35:51Imagine you're walking along the shoreline when you come across this.
0:35:52 > 0:35:56You probably wouldn't give this rocky outcrop a second look.
0:35:57 > 0:36:00Unless, of course, you're a local.
0:36:02 > 0:36:05Because they know that there's more to this lump than meets the eye.
0:36:11 > 0:36:14Gives new meaning to blood from a stone.
0:36:17 > 0:36:20But this weird lump is actually alive.
0:36:22 > 0:36:24It's pyura,
0:36:24 > 0:36:28a filter feeder that grows in rocky clumps along the tide line.
0:36:30 > 0:36:34Its hard exterior hides a soft, gooey centre that these
0:36:34 > 0:36:38locals consider a seaside delicacy.
0:36:39 > 0:36:42A bit like an oyster, delicious...
0:36:44 > 0:36:45PEOPLE YELL
0:36:47 > 0:36:48..well, apparently.
0:36:51 > 0:36:53HE EXCLAIMS
0:36:53 > 0:36:55Now, Chilean taste buds are one thing,
0:36:55 > 0:36:59but its the lifestyle of this living rock that's truly bizarre.
0:37:06 > 0:37:09It actually starts life as a tiny tadpole.
0:37:10 > 0:37:15Before fixing itself in position and turning into a living rock.
0:37:17 > 0:37:19Stuck fast.
0:37:20 > 0:37:22Which is a problem.
0:37:22 > 0:37:27I mean, how does a male rock find a female rock and make tadpoles?
0:37:30 > 0:37:34Well, it's easy if you're actually male and female.
0:37:38 > 0:37:42Yes, the living rock needs to look no further than itself to procreate.
0:37:45 > 0:37:48Surely it can't get any weirder than
0:37:48 > 0:37:52a self-fertilizing, sex changing invertebrate masquerading as a rock?
0:37:53 > 0:37:55Oh, but, yes, it can.
0:37:59 > 0:38:03Because our gooey geode has a backbone.
0:38:04 > 0:38:08No, really, it's true. It develops at the tadpole stage.
0:38:10 > 0:38:12And then compare it to,
0:38:12 > 0:38:15I don't know, a human embryo.
0:38:16 > 0:38:17See any similarities?
0:38:20 > 0:38:24The living rock evolved this kind of backbone at the same time
0:38:24 > 0:38:26our ancestors did
0:38:26 > 0:38:32some 600 million years ago. Cutting straight to the uncomfortable truth.
0:38:37 > 0:38:39We're related.
0:38:42 > 0:38:48This super strange pseudo-rock is our closest invertebrate cousin.
0:38:48 > 0:38:49It's quite hard to swallow.
0:38:52 > 0:38:57An underwater wonderland created by the seasons.
0:38:57 > 0:39:02A green colony that's seen centuries pass.
0:39:02 > 0:39:07And our rocky relatives, unchanged for thousands of years.
0:39:07 > 0:39:12And apparently, delicious. But do you know what, I think
0:39:12 > 0:39:14I'll take their word for it.
0:39:17 > 0:39:20Finally, we're going to get very hot and bothered
0:39:20 > 0:39:24when we meet one of the world's most dangerous meteorological phenomena.
0:39:26 > 0:39:30'And discover the science behind a very strange
0:39:30 > 0:39:31'fire extinguishing invention.
0:39:31 > 0:39:34'But first, a trip to the States.'
0:39:38 > 0:39:42The Florida Keys, in fact, renowned for their long, sandy beaches,
0:39:42 > 0:39:46deep blue waters, and beautiful sunny days.
0:39:48 > 0:39:53But on the 25th of September 2013, a local fisherman found himself at the
0:39:53 > 0:39:56centre of some very strange weather.
0:40:04 > 0:40:06On that day I was out enjoying a typical summer day
0:40:06 > 0:40:09with my friend Erin and we were catching lobster.
0:40:12 > 0:40:16During the course of that time we had seen this cloud on the horizon.
0:40:20 > 0:40:21We thought that there was the
0:40:21 > 0:40:24potential for something to happen but we didn't recognise how
0:40:24 > 0:40:26great an event it was going to become.
0:40:27 > 0:40:29What he thought was just another cloud,
0:40:29 > 0:40:33turned out to be something much weirder.
0:40:33 > 0:40:35As we approached the base of this cloud it was a rapidly
0:40:35 > 0:40:37changing formation.
0:40:37 > 0:40:39This was something that caught us off guard
0:40:39 > 0:40:41and we couldn't have prepared for.
0:40:42 > 0:40:48It was a waterspout and Kevin was headed straight for it.
0:40:49 > 0:40:52Look at the funnel starting on this. Looks like it's getting angry.
0:40:54 > 0:40:57So what creates these strange, spinning spouts?
0:41:00 > 0:41:04The basic ingredients of a waterspout are a warm water surface
0:41:04 > 0:41:06and a storm cloud over the top of that surface.
0:41:12 > 0:41:15All sorts of places are prone to them,
0:41:15 > 0:41:17the Great Lakes of North America,
0:41:17 > 0:41:20the Mediterranean gets a lot of water spouts.
0:41:20 > 0:41:23They can even form in a swimming pool!
0:41:26 > 0:41:28And although they look bizarre,
0:41:28 > 0:41:32the science behind these spouts is actually fairly simple.
0:41:32 > 0:41:34We can even make our own in miniature.
0:41:39 > 0:41:43The dry ice represents warm air rising from the ocean surface.
0:41:44 > 0:41:49It forms a column that draws in surrounding water and clouds.
0:41:49 > 0:41:53This cloud-filled column starts to rotate,
0:41:53 > 0:41:56creating a whirling vortex, a waterspout.
0:41:59 > 0:42:01On a hot, stormy day
0:42:01 > 0:42:04weather conditions can be ideal for making waterspouts.
0:42:05 > 0:42:06Perhaps a little too ideal.
0:42:09 > 0:42:13Just off the coast of Liguria, Italy, a passer-by captured this
0:42:13 > 0:42:15footage of something incredible...
0:42:17 > 0:42:18..twin waterspouts.
0:42:21 > 0:42:24If under a particular cloud there's more than one column of air
0:42:24 > 0:42:27rising at a time, then you can get multiple waterspouts.
0:42:32 > 0:42:34Back in Florida, Kevin
0:42:34 > 0:42:37was surrounded not by one, or even two spouts.
0:42:39 > 0:42:40They're everywhere.
0:42:40 > 0:42:44There's one, two, three, four and a fifth over there.
0:42:45 > 0:42:47Look how fast it's spinning.
0:42:49 > 0:42:54So, multiple spouts is a very real, very weird possibility.
0:42:54 > 0:42:59But there is one thing crazier than a sky full of raging vortices
0:42:59 > 0:43:00and that's this man.
0:43:03 > 0:43:05I think we should go inside!
0:43:05 > 0:43:08All right, let's go, we're going to batten down the hatches,
0:43:08 > 0:43:11put on the waterproof housing and we are going inside.
0:43:12 > 0:43:16Kevin was playing with fire... well, water.
0:43:19 > 0:43:22There is a million decisions going on.
0:43:22 > 0:43:25Can I really do this? What are the repercussions and
0:43:25 > 0:43:29who's going to get mad at me and who's going to see this?
0:43:29 > 0:43:31My girlfriend's going to kill me.
0:43:36 > 0:43:39Aah!
0:43:47 > 0:43:50Your ears pop, you feel the hairs on your neck stand up on end.
0:43:56 > 0:44:00It was such a sensory overload, your body didn't know how to react
0:44:00 > 0:44:03to it and your brain didn't have time to process
0:44:03 > 0:44:06so the first emotion to come out was pure joy.
0:44:06 > 0:44:09That opened all my hatches and everything.
0:44:11 > 0:44:15Kevin sailed through a spout and lived to tell the tale.
0:44:17 > 0:44:20He was very lucky, the boat only suffered
0:44:20 > 0:44:23some minor damage, war wounds, really.
0:44:25 > 0:44:26We won't do that again.
0:44:28 > 0:44:33- And just in case you felt yourself asking...- No animals were
0:44:33 > 0:44:35harmed in the making of this film.
0:44:37 > 0:44:42Now, Kevin and his friend survived their adventure because waterspouts
0:44:42 > 0:44:45aren't necessarily that powerful.
0:44:45 > 0:44:48The vortices that he filmed weren't spinning fast enough to
0:44:48 > 0:44:50lift the boat from the water.
0:44:52 > 0:44:57'But when a vortex forms over land it becomes
0:44:57 > 0:44:59'a very different beast altogether.'
0:45:01 > 0:45:05April 27th, 2011, Alabama.
0:45:07 > 0:45:10And a drive to work is about to take a very frightening turn.
0:45:13 > 0:45:15SCREAMING
0:45:18 > 0:45:22I heard on the radio there were weather warnings
0:45:22 > 0:45:25but living in the south you brush them off.
0:45:28 > 0:45:30When it started to
0:45:30 > 0:45:32get 150, 100 yards near me,
0:45:32 > 0:45:34I knew it was coming towards me.
0:45:36 > 0:45:39Lauren's commute was cut short.
0:45:41 > 0:45:46- Oh, my God.- Something terrifying was coming right for her.
0:45:47 > 0:45:50You could hear the rocks hitting my car.
0:45:53 > 0:45:56About ten seconds after that, that's when it hit me.
0:45:56 > 0:45:57LAUREN SCREAMS
0:46:00 > 0:46:02I stood no chance, at all.
0:46:07 > 0:46:11Lauren had found herself in the path of a spinning vortex.
0:46:11 > 0:46:14But unlike the water spout that Kevin encountered,
0:46:14 > 0:46:17this thing was much more dangerous.
0:46:21 > 0:46:23I threw my car in reverse...
0:46:26 > 0:46:28..and did a 180.
0:46:28 > 0:46:30I put my foot all the way down and tried to get
0:46:30 > 0:46:32out of there as fast as I could.
0:46:35 > 0:46:37I just remember closing my eyes.
0:46:37 > 0:46:39SCREAMING
0:46:43 > 0:46:46It pushed me into a building and sucked me back out.
0:46:49 > 0:46:52Unlike Kevin, Lauren wasn't left smiling.
0:46:54 > 0:46:58This vortex ripped her car from the ground, spinning it skyward.
0:47:00 > 0:47:01I thought I was going to die.
0:47:08 > 0:47:12I look around and see all the damage that it did, not only to my car
0:47:12 > 0:47:14but to everything else.
0:47:24 > 0:47:27'So where had all this power come from?'
0:47:28 > 0:47:30Well, it was a hot day in Alabama
0:47:30 > 0:47:35and the clouds forming over Lauren's head were much bigger.
0:47:37 > 0:47:40And bigger clouds mean bigger vortexes.
0:47:45 > 0:47:49Just like waterspouts, it's all about hot air.
0:47:51 > 0:47:54The hot ground heats the air, sending it skywards.
0:47:57 > 0:47:59Then winds at different altitudes
0:47:59 > 0:48:02blowing at different speeds make the column of hot air spin.
0:48:06 > 0:48:10As the column rises higher, it spins faster
0:48:10 > 0:48:13and faster and becomes more powerful.
0:48:20 > 0:48:25Now it's a tornado spinning at up to 300mph.
0:48:28 > 0:48:31Giving it, as footage from this Indiana high school proves,
0:48:31 > 0:48:35the power to destroy everything in its path.
0:48:47 > 0:48:50Tornados are classified by how powerful they are
0:48:50 > 0:48:52and how much destruction they do.
0:48:52 > 0:48:55And they range from an EF-0 tornado, which is a very light,
0:48:55 > 0:48:57weak tornado...
0:49:00 > 0:49:03..right up to EF-5, which is a very destructive storm that can
0:49:03 > 0:49:05blow over trees,
0:49:05 > 0:49:08knock down houses, even pick up cars and move them some distance.
0:49:13 > 0:49:19Lauren had survived a first-hand encounter with an EF-5 tornado.
0:49:20 > 0:49:24She was very lucky to make it out alive.
0:49:24 > 0:49:29Don't mess with Mother Nature because she is mean sometimes.
0:49:33 > 0:49:37Lauren had gone head-to-head with a meteorological monster
0:49:37 > 0:49:42and lived to tell the tale, but the tornado has an altogether
0:49:42 > 0:49:46stranger cousin that leaves no survivors.
0:49:50 > 0:49:52The Australian outback.
0:49:52 > 0:49:55One of the most extreme environments on the planet.
0:49:57 > 0:50:01Temperatures here can soar to 40 Celsius.
0:50:02 > 0:50:06And the parched bush is like tinder to a flame.
0:50:09 > 0:50:12Wildfires are a force to be reckoned with.
0:50:14 > 0:50:19But from the belly of the fire comes an altogether different beast.
0:50:22 > 0:50:25It's only been captured on film a few times.
0:50:27 > 0:50:28But it's utterly spectacular.
0:50:34 > 0:50:36The firenado.
0:50:38 > 0:50:41A swirling vortex of fire reaching high into the sky.
0:50:43 > 0:50:46These things may look like a special effect,
0:50:46 > 0:50:49but they're not, they're very real, they're very powerful
0:50:49 > 0:50:52and they're very dangerous.
0:50:52 > 0:50:56And the weirdest thing about them, notice there are no clouds.
0:50:58 > 0:51:00There's no storm.
0:51:00 > 0:51:04A firenado doesn't need outside help to wreak havoc.
0:51:15 > 0:51:19You see, the fire generates very hot air,
0:51:19 > 0:51:23rising in a column that starts to spin.
0:51:24 > 0:51:27It produces its own tornado.
0:51:27 > 0:51:32And then you get this strange, spinning, raging, fiery hybrid.
0:51:37 > 0:51:40The vortex sucks flames from the wildfire below.
0:51:42 > 0:51:45And combustible gases from the air all around it...
0:51:46 > 0:51:49..creating a jet engine-like inferno
0:51:49 > 0:51:54with a core that can reach over 1,000 degrees Celsius.
0:52:04 > 0:52:07Experts studying a bush fire in Australia
0:52:07 > 0:52:11found a 25-kilometre strip of torched earth,
0:52:11 > 0:52:15tracing the path of just one of these fiery beasts.
0:52:18 > 0:52:20We might have given it a Hollywood name
0:52:20 > 0:52:23but the firenado is a weird weather phenomena
0:52:23 > 0:52:26not to be trifled with.
0:52:33 > 0:52:37Fire is one of the most devastating forces on earth
0:52:37 > 0:52:39and fighting it is a real challenge.
0:52:39 > 0:52:41So what have we got at our disposal?
0:52:41 > 0:52:44Well, we've got sand - plenty of that around here,
0:52:44 > 0:52:49or we've got CO2, water, foam...
0:52:50 > 0:52:54But in Virginia, USA, two engineering students have come up
0:52:54 > 0:52:58with an extraordinary, new flame extinguishing solution.
0:53:01 > 0:53:05A patented design that they hope will reinvent firefighting.
0:53:11 > 0:53:14The first time that we were able to show it to the fire marshals -
0:53:14 > 0:53:16these people that see fire every day -
0:53:16 > 0:53:19they see it going out instantly, they are like,
0:53:19 > 0:53:21"Wow! What is this? Why do we not use this?"
0:53:22 > 0:53:24MACHINE HUMS
0:53:27 > 0:53:29The concept itself is not new
0:53:29 > 0:53:32but nothing practical has ever come about.
0:53:32 > 0:53:33Nothing that can really be used.
0:53:35 > 0:53:37We know how devastating fire can be,
0:53:37 > 0:53:42but putting it out is just as dangerous.
0:53:49 > 0:53:53The problem is that different substances burn in different ways,
0:53:53 > 0:53:56which means that when it comes to extinguishing them,
0:53:56 > 0:53:57you need to use different methods.
0:53:57 > 0:54:00and if you get it wrong, it can be disastrous.
0:54:00 > 0:54:04Like throwing water on a burning chip fat fryer in the kitchen.
0:54:07 > 0:54:12So Seth and Viet saw a gap in the market for a simple solution.
0:54:13 > 0:54:15A lot of people freak out and throw water on it.
0:54:15 > 0:54:17That's the worst thing you could do for a grease fire.
0:54:17 > 0:54:20We designed it to work on liquid fires and things of that nature.
0:54:23 > 0:54:26But this wasn't to be your average extinguisher.
0:54:27 > 0:54:32Seth and Viet had something more unusual in mind.
0:54:32 > 0:54:36An idea so outlandish that, at first, well,
0:54:36 > 0:54:38everyone thought they were a bit mad.
0:54:40 > 0:54:42The person that leads the class, he's telling us, you know,
0:54:42 > 0:54:44you guys should know if it doesn't work,
0:54:44 > 0:54:46you've put yourselves at risk of failing the class.
0:54:46 > 0:54:49With their engineering degrees on the line,
0:54:49 > 0:54:52Seth and Viet still dared to dream.
0:54:52 > 0:54:56It came down to this technology is going to happen one day.
0:54:56 > 0:54:58Why not us be the ones to create it?
0:55:01 > 0:55:04Seth and Viet weren't working on a miraculous powder
0:55:04 > 0:55:07or some sort of fire dampening fluid.
0:55:07 > 0:55:11No. They believed that an invisible force could be
0:55:11 > 0:55:13channeled to extinguish the flames.
0:55:17 > 0:55:18They'd made...
0:55:20 > 0:55:21..the world's first...
0:55:23 > 0:55:25MACHINE HUMS
0:55:25 > 0:55:27..sound extinguisher.
0:55:27 > 0:55:31This is the first time that a device like this has actually been put into practice.
0:55:31 > 0:55:33MACHINE HUMS
0:55:34 > 0:55:36But how does it work?
0:55:37 > 0:55:42Well, this sound generating, flame-busting, backpack
0:55:42 > 0:55:44is based on some very simple science.
0:55:52 > 0:55:57For a fire to burn, it needs both fuel and oxygen.
0:55:57 > 0:56:01If you take one of these away, it simply can't burn any more.
0:56:04 > 0:56:10Seth and Viet realised that you could use sound to split these elements.
0:56:10 > 0:56:12WHISTLING SOUND
0:56:15 > 0:56:17This should make things clearer.
0:56:19 > 0:56:21So we know that sound moves in waves.
0:56:24 > 0:56:27Send sound waves through a gas-filled tube,
0:56:27 > 0:56:29light it,
0:56:29 > 0:56:31and you can clearly see the wave pattern.
0:56:34 > 0:56:37Changing the volume and frequency of sound
0:56:37 > 0:56:39changes the shape of the wave.
0:56:41 > 0:56:46What the guys had realised is that specific frequencies of sound waves,
0:56:46 > 0:56:48combined together,
0:56:48 > 0:56:51could separate the oxygen from the fuel,
0:56:51 > 0:56:54thus extinguishing the flames.
0:56:58 > 0:57:01This is just the start for the sound extinguisher.
0:57:01 > 0:57:03MACHINE HUMS
0:57:03 > 0:57:05It has potential far beyond the kitchen.
0:57:07 > 0:57:10It would be awesome to see this being applied,
0:57:10 > 0:57:14just attached to drones and swarms of them attacking a forest fire,
0:57:14 > 0:57:16building fires - that'd be really cool to see.
0:57:16 > 0:57:20Putting human life out of harm's way.
0:57:20 > 0:57:24Engineering is all about finding a way to make the impossible, possible. So that's what we did.
0:57:27 > 0:57:31So, in the future, we might be fighting fire with big beats
0:57:31 > 0:57:33instead of water hoses.
0:57:35 > 0:57:39But in the meantime, if you hear the roar of wind
0:57:39 > 0:57:42and see a spinning vortex spewing flames...
0:57:44 > 0:57:46..hurtling over land,
0:57:46 > 0:57:49or whipping up water...
0:57:51 > 0:57:52- ..don't do a Kevin. - Ha-ha, ha!
0:57:52 > 0:57:53Argh!
0:57:53 > 0:57:55Stay out of its way.
0:57:58 > 0:58:02All very curious and strange stuff.
0:58:02 > 0:58:05But I can assure you there's a bit more weirdery to come yet.
0:58:09 > 0:58:10Next time...
0:58:10 > 0:58:14How does a lake form at the bottom of the ocean?
0:58:16 > 0:58:19Does money really grow on trees?
0:58:20 > 0:58:24How does a kingfisher help design a super-fast train?
0:58:26 > 0:58:29And could robot swarms cure cancer?