0:00:02 > 0:00:04- Welcome to the genius world of... - BOTH:- Monster engineering!
0:00:04 > 0:00:06- Argh!- Argh!- Argh!
0:00:06 > 0:00:10'Each show, we're going to introduce you to three geniuses...'
0:00:10 > 0:00:12- Wow!- Oh!
0:00:12 > 0:00:15..whose ideas have quite literally built the world.
0:00:16 > 0:00:18'We put all their epic brilliance...'
0:00:18 > 0:00:19Yes!
0:00:19 > 0:00:21- '..to the test...'- Hit it! Hit it!
0:00:21 > 0:00:24'..when we tackle our own genius monster build.'
0:00:24 > 0:00:26Don't you dare demolish this!
0:00:27 > 0:00:30- 'Going higher...' - Why is it swinging?!
0:00:30 > 0:00:31'..faster...'
0:00:33 > 0:00:34'..and scarier...'
0:00:34 > 0:00:36Oh, no! No!
0:00:36 > 0:00:37'..all in the name of science.'
0:00:37 > 0:00:40That is a massive piece of construction.
0:00:40 > 0:00:42What could possibly go wrong?
0:00:47 > 0:00:49- On this show... - HE SCREAMS
0:00:49 > 0:00:51..we're dodging...
0:00:51 > 0:00:53All right, you fighter.
0:00:53 > 0:00:55..ducking...
0:00:55 > 0:00:56Oh, I got the camera!
0:00:56 > 0:00:58..and defending.
0:00:58 > 0:01:00'Help!' HE SCREAMS
0:01:00 > 0:01:03- 'Cos we're under attack!'- Yeah!
0:01:03 > 0:01:05- This is...- Absolute Genius.
0:01:41 > 0:01:42Throughout history,
0:01:42 > 0:01:45we've needed to defend ourselves against attack,
0:01:45 > 0:01:47and what better way than through the work
0:01:47 > 0:01:51of our three engineering geniuses who've helped keep us out of danger?
0:01:58 > 0:02:00For as long as we've walked the earth,
0:02:00 > 0:02:02people have found things to fight about.
0:02:02 > 0:02:03Mine! Mine!
0:02:03 > 0:02:08Arguments over land, water and even ideas can all end up in,
0:02:08 > 0:02:10well, a punch-up, basically.
0:02:10 > 0:02:12And as we got better at launching attacks,
0:02:12 > 0:02:15engineers have had to come up with smarter and smarter ways
0:02:15 > 0:02:17of keeping the baddies at bay.
0:02:17 > 0:02:19THEY LAUGH MOCKINGLY
0:02:23 > 0:02:26Let's start back in a time when knights were bold
0:02:26 > 0:02:29and damsels always seemed to be in distress.
0:02:29 > 0:02:32Life in the Middle Ages was a pretty dodgy affair.
0:02:32 > 0:02:34Yeah, it was. There were loads of warring armies and bandits,
0:02:34 > 0:02:37which meant that staying out of danger was top of the list.
0:02:37 > 0:02:39So, what better way to stay safe
0:02:39 > 0:02:41than through the work of our first genius?
0:02:41 > 0:02:43Please welcome castle builder extraordinaire,
0:02:43 > 0:02:46James of Saint George.
0:02:46 > 0:02:49- FRENCH ACCENT:- Keep out of my beautiful castle, you naughty men!
0:02:50 > 0:02:52THEY BLOW RASPBERRIES
0:02:54 > 0:02:57Euryn Roberts is a medieval history expert.
0:02:57 > 0:02:59What he doesn't know about Beaumaris Castle
0:02:59 > 0:03:03and the man who built it isn't worth knowing.
0:03:03 > 0:03:06Why is this castle so significant to James of Saint George?
0:03:06 > 0:03:08Well, this is his last castle in Wales.
0:03:08 > 0:03:10He built a number in Wales and a few in Scotland,
0:03:10 > 0:03:14as well, but this is the last one, the greatest in terms of its scale.
0:03:14 > 0:03:15When the warring armies came along,
0:03:15 > 0:03:18how difficult would it have been for them to storm this castle?
0:03:18 > 0:03:19Well, as you can see,
0:03:19 > 0:03:21we've got two massive curtain walls in front of us.
0:03:21 > 0:03:24We've got a moat surrounding the castle, as well.
0:03:24 > 0:03:26It's designed to keep people out.
0:03:26 > 0:03:31This incredible castle is fortified to the max.
0:03:31 > 0:03:34Anyone who wanted to storm this place would've faced no fewer
0:03:34 > 0:03:37than 14 separate obstacles.
0:03:37 > 0:03:42But it's never been put to the test by a besieging army until now.
0:03:42 > 0:03:43There's only one way to find out
0:03:43 > 0:03:46whether James of Saint George's genius defences were the real deal.
0:03:46 > 0:03:50It's time for a Dick versus Dom castle concrete challenge.
0:03:52 > 0:03:55I'm sticking with Euryn, who's giving me the inside track
0:03:55 > 0:03:57on James of Saint George's finest creation.
0:03:57 > 0:03:59While I'm on the attack.
0:03:59 > 0:04:03Right, that castle is under siege.
0:04:03 > 0:04:05Just have to remember how to row.
0:04:05 > 0:04:08What was it about the moat that made it so difficult to cross?
0:04:08 > 0:04:10So, the moat is the first line of defence.
0:04:10 > 0:04:12As you can see, it's pretty wide.
0:04:12 > 0:04:14It would've been up to a man's chest.
0:04:14 > 0:04:16And if you've got people throwing things down at you,
0:04:16 > 0:04:19shooting at you, it's going to be pretty difficult to get over.
0:04:19 > 0:04:21OK. Right, what's the next one?
0:04:22 > 0:04:25Don't go! I'm about to siege!
0:04:25 > 0:04:27I'm going to attack you! Oh!
0:04:27 > 0:04:30If Dom does eventually make it across that moat,
0:04:30 > 0:04:35he'll come face-to-face with these huge, 12m-high stone walls.
0:04:35 > 0:04:37Right, I'm hot on your heels,
0:04:37 > 0:04:40but not before I've slipped into something a little, well,
0:04:40 > 0:04:41less comfortable.
0:04:41 > 0:04:43He's going to be terrified when he sees me.
0:04:43 > 0:04:45We're pretty high up. Why is this a good defence?
0:04:45 > 0:04:49So, we're on top of the inner ward.
0:04:49 > 0:04:52If you remember, there was the moat, then there's the outer ward.
0:04:52 > 0:04:56But in between the inner and outer ward,
0:04:56 > 0:04:58we've got this area of grass here.
0:04:58 > 0:05:00People would've been throwing things down at you,
0:05:00 > 0:05:02firing arrows at you.
0:05:02 > 0:05:03It wouldn't have been a nice place to be.
0:05:03 > 0:05:06King Dickie, I'm coming for you! Argh!
0:05:07 > 0:05:12We've got just the thing to dampen the enthusiasm of troublemakers -
0:05:12 > 0:05:14water bombs.
0:05:14 > 0:05:16Oh! Close!
0:05:16 > 0:05:18- Argh!- All right, you fighter. - Hey-ah!
0:05:18 > 0:05:20- Oh, missed again. - Have some of that.- Missed.
0:05:20 > 0:05:22Oh! Cheeky.
0:05:22 > 0:05:24You, sir, are French toast.
0:05:24 > 0:05:26Come on! I'm invading your castle!
0:05:29 > 0:05:31Missed.
0:05:31 > 0:05:33We're getting the range. We're getting the range.
0:05:33 > 0:05:35Oh, cheeky.
0:05:35 > 0:05:38All right!
0:05:38 > 0:05:39He's getting off really lightly,
0:05:39 > 0:05:41but of course, in the medieval period,
0:05:41 > 0:05:45we'd be shooting arrows at him, throwing boiling water on him.
0:05:46 > 0:05:49Your chain mail is all soggy now, monsieur.
0:05:49 > 0:05:51Argh!
0:05:51 > 0:05:53'Right, that's it. I'm trying another way in.
0:05:55 > 0:05:56'Whatever.'
0:05:56 > 0:05:58Around the other side of the inner ward
0:05:58 > 0:06:01is the South Gate passage.
0:06:01 > 0:06:04It's one of only two routes into the heart of the castle,
0:06:04 > 0:06:07and there's certainly no welcome mat here.
0:06:07 > 0:06:09You'd have had to get through a big wooden door
0:06:09 > 0:06:10to get into this area.
0:06:10 > 0:06:14- You would've had to get past a portcullis.- What's a portcullis?
0:06:14 > 0:06:17A portcullis is a big iron gate, and there's two in here.
0:06:17 > 0:06:20One on the front and one towards the back.
0:06:20 > 0:06:22You can see this is the groove where it would've fallen down.
0:06:22 > 0:06:26And then, above us, there were murder holes.
0:06:26 > 0:06:27Oh, don't like the sound of them.
0:06:27 > 0:06:29So, murder holes were kind of spaces
0:06:29 > 0:06:33where people would throw down boiling water, stones.
0:06:33 > 0:06:37And then, just behind you, we have arrow slits.
0:06:37 > 0:06:38They're quite narrow in the front,
0:06:38 > 0:06:41but they're wider inside and there would've been room there
0:06:41 > 0:06:43for people to fire arrows at you.
0:06:43 > 0:06:45So, not only you get melted, you get an arrow in the head, as well.
0:06:45 > 0:06:47- Yeah. And you're trapped, as well.- Oh.
0:06:47 > 0:06:48You're not getting any further.
0:06:48 > 0:06:50Don't like this place. Let's move on.
0:06:50 > 0:06:53It doesn't scare me.
0:06:53 > 0:06:55- I'm going to get my castle back. WHISPERS:- Here he is coming.
0:06:58 > 0:06:59Shh!
0:07:02 > 0:07:03Oh!
0:07:03 > 0:07:05Right, that's it. I admit, it's terrifying.
0:07:05 > 0:07:08It's a naughty castle and I can't cope.
0:07:08 > 0:07:10- HE SCREAMS - Ha-ha! He's legged it.
0:07:10 > 0:07:12It's victory for engineering.
0:07:13 > 0:07:15- Thank goodness that's all over. - Why, was it heavy?
0:07:15 > 0:07:16No, it was just ridiculous, wasn't it?
0:07:16 > 0:07:18But anyway, the point has been proved
0:07:18 > 0:07:21- that I could not enter your castle. - No, I am the king of the castle.
0:07:21 > 0:07:26No, no, no, c'est moi. I am the king of the castles!
0:07:28 > 0:07:30Engineering against attack
0:07:30 > 0:07:32isn't always about the design of the building.
0:07:32 > 0:07:35No, it's also about the materials that you use to build it.
0:07:35 > 0:07:37Yeah. Since the 19th century,
0:07:37 > 0:07:40one genius material has withstood bombs, bullets and blasts
0:07:40 > 0:07:42more than any other material.
0:07:42 > 0:07:45Introducing reinforced concrete
0:07:45 > 0:07:48and its inventor Monsieur Joseph Monier.
0:07:49 > 0:07:52Come and have a go if you think you're 'ard enough.
0:07:52 > 0:07:55- Concrete lover. - He's a concrete kisser.
0:07:55 > 0:07:56We love concrete, we do.
0:07:58 > 0:08:01Frenchman Joseph Monier was a keen gardener
0:08:01 > 0:08:03with a big problem.
0:08:03 > 0:08:06The clay pots that he used to hold his plants would often break.
0:08:06 > 0:08:07Oh, no!
0:08:07 > 0:08:08Needing something stronger,
0:08:08 > 0:08:11he put a layer of iron mesh inside cement.
0:08:11 > 0:08:15Monier's new material was much tougher to smash
0:08:15 > 0:08:17and it wasn't long before he realised its potential
0:08:17 > 0:08:19for building bigger things.
0:08:19 > 0:08:22May the reinforced be with you. Ha!
0:08:22 > 0:08:24But it was during World War II
0:08:24 > 0:08:27that Monier's genius idea came into full force.
0:08:27 > 0:08:28Yeah, the British and the Germans
0:08:28 > 0:08:31were making massive use of reinforced concrete.
0:08:31 > 0:08:34They were using it to build barriers, bunkers
0:08:34 > 0:08:36and other defensive buildings.
0:08:36 > 0:08:38The biggest and the best of the lot was this.
0:08:40 > 0:08:43This huge dome is called La Coupole.
0:08:43 > 0:08:46During the Second World War, this site in Northern France
0:08:46 > 0:08:51was used by the German army to store and launch V-2 rockets.
0:08:53 > 0:08:56This made it a massive target for Allied attacks.
0:08:59 > 0:09:02But nowadays, it's kept as a museum.
0:09:03 > 0:09:08And Genius helper Cyrille Delattre is going to show us around.
0:09:08 > 0:09:11Right, we're in the top of the building,
0:09:11 > 0:09:12but what was this dome used for?
0:09:12 > 0:09:14Actually, this dome is very special.
0:09:14 > 0:09:17What is very important is under our feet, actually -
0:09:17 > 0:09:19the preparation room for the rockets.
0:09:19 > 0:09:21It needed to be protected,
0:09:21 > 0:09:24so they needed to build this kind of huge shield of concrete
0:09:24 > 0:09:26to protect what is underground.
0:09:26 > 0:09:28So, this is like basically a giant umbrella.
0:09:28 > 0:09:31- It is a giant umbrella. - A big, concrete umbrella.
0:09:31 > 0:09:32Definitely.
0:09:32 > 0:09:34And it's, as you can see, very much reinforced.
0:09:34 > 0:09:35- You can see up there...- Oh, yeah.
0:09:35 > 0:09:38..these big bars of metal crisscross.
0:09:38 > 0:09:40It's like a giant Shreddie.
0:09:40 > 0:09:43This would go like this and then this and then this...
0:09:43 > 0:09:44- Yes.- ..all the way up.
0:09:44 > 0:09:49In total, the Germans used about 55,000 tonnes of concrete here.
0:09:49 > 0:09:53The reinforced dome is 5m thick,
0:09:53 > 0:09:55which gave the builders a real headache when it came
0:09:55 > 0:09:57to fitting the museum's fire exits.
0:10:00 > 0:10:05It took almost ten months just to dig this small exit.
0:10:05 > 0:10:07What?! But that's the same amount of time
0:10:07 > 0:10:10as it took the Germans to build the whole building.
0:10:10 > 0:10:11Definitely.
0:10:11 > 0:10:15That gives you a good clue of the efficiency of the construction.
0:10:15 > 0:10:18So, why did it take so long to dig through, what is it, 5m?
0:10:18 > 0:10:19Well, yes, 5m.
0:10:19 > 0:10:23But you must think of the resistance of the concrete in itself
0:10:23 > 0:10:24and the reinforcements.
0:10:24 > 0:10:26You can see it's everywhere.
0:10:26 > 0:10:30Reinforced concrete is clearly no soft touch.
0:10:30 > 0:10:34But why exactly is it so resistant to attack?
0:10:37 > 0:10:40In case you haven't noticed, we're not engineers.
0:10:40 > 0:10:43- THEY SCREAM - Oh, what?!
0:10:43 > 0:10:46So it's a good job we have superstar engineer Yewande
0:10:46 > 0:10:49to call on when structures get us scratching our heads.
0:10:49 > 0:10:51Argh!
0:10:51 > 0:10:54- Yewande, what have you got in there? - I've got cake mixture in here.
0:10:54 > 0:10:56Of course you have. Why have you got cake mixture?
0:10:56 > 0:10:58We're here to talk about reinforced concrete.
0:10:58 > 0:10:59Yes, but you know what?
0:10:59 > 0:11:03Cake and concrete actually have a lot in common.
0:11:03 > 0:11:05- Is it rock cake? - HE CHUCKLES
0:11:05 > 0:11:08- What is this? What is that? - This is plastic.
0:11:08 > 0:11:10'It's baking mesh.'
0:11:10 > 0:11:13Now, this is like the reinforcement -
0:11:13 > 0:11:15the iron or the steel, right?
0:11:15 > 0:11:19It is able to withstand bending forces, right?
0:11:19 > 0:11:21It's got the right give.
0:11:21 > 0:11:25And the concrete - our cake mixture -
0:11:25 > 0:11:29is able to actually bear compressive stresses.
0:11:29 > 0:11:31Concrete alone can shatter when hit.
0:11:31 > 0:11:34Add in the flexible strength of steel, and voila,
0:11:34 > 0:11:37you have one mega-strong material.
0:11:37 > 0:11:39Joseph Monier, that was his genius.
0:11:39 > 0:11:42He combined two different materials
0:11:42 > 0:11:44with two different physical properties
0:11:44 > 0:11:49to create one material that is stronger than either
0:11:49 > 0:11:52of the two materials would've been on their own.
0:11:52 > 0:11:53And Yewande has come up
0:11:53 > 0:11:56with a little experiment to prove exactly that.
0:11:56 > 0:12:01One of these cakes is reinforced with layers of plastic baking mesh,
0:12:01 > 0:12:03and the other, well, it isn't.
0:12:03 > 0:12:06Here's two we made earlier.
0:12:06 > 0:12:09Now, which will survive this 6m drop?
0:12:09 > 0:12:13One, two, three.
0:12:20 > 0:12:22Right, let's have a look.
0:12:22 > 0:12:24- OK. I'll and try and pick it up. - Oh, my God.- Oh.
0:12:24 > 0:12:26- Oh, look at that. - How about we try that one?
0:12:26 > 0:12:29That is intact thanks to the reinforcement.
0:12:29 > 0:12:31- Point proven.- Definitely.
0:12:31 > 0:12:33The bad news is my cake is in pieces.
0:12:33 > 0:12:35The good news is it tastes blooming good.
0:12:35 > 0:12:37Put the kettle on. We'll have a nice cup of tea.
0:12:37 > 0:12:39Have a brew, yeah. Come on, let's go and have a brew.
0:12:39 > 0:12:41The proof is in the pudding.
0:12:42 > 0:12:44Back on the other side of the English Channel,
0:12:44 > 0:12:46Cyrille has arranged a special treat.
0:12:46 > 0:12:48A trip to the very top
0:12:48 > 0:12:51of La Coupole's reinforced concrete dome.
0:12:51 > 0:12:54- Wow, look at the view. - Yes, it is a beautiful view,
0:12:54 > 0:12:59- although, around here, 3,000 tonnes of bombs fell...- Whoa.
0:12:59 > 0:13:01..that was dropped by the Royal Air Force
0:13:01 > 0:13:02during the Second World War.
0:13:02 > 0:13:05One of the biggest bombs of the time, a Tallboy -
0:13:05 > 0:13:08- five tonnes - just fell 20 yards from here.- Yeah.
0:13:08 > 0:13:11It should have shaken everything off,
0:13:11 > 0:13:16and the dome resisted because of the reinforcement.
0:13:16 > 0:13:18Since the end of World War II,
0:13:18 > 0:13:20Monier's genius idea has kept everything,
0:13:20 > 0:13:22from the world's tallest buildings
0:13:22 > 0:13:25to the most famous bridges, standing.
0:13:28 > 0:13:31Joseph Monier, you are one tough cookie.
0:13:31 > 0:13:34- And of course an absolute genius. - Mwah!
0:13:34 > 0:13:36Get off!
0:13:36 > 0:13:37Tastes like concrete.
0:13:40 > 0:13:45Still to come, we head to the seaside to build,
0:13:45 > 0:13:46and then attempt to knock down...
0:13:46 > 0:13:48No! My beautiful wall!
0:13:48 > 0:13:51..a massive castle of our very own.
0:13:51 > 0:13:52Stop!
0:13:52 > 0:13:56But now prepare yourselves for a barrage of random genius-nesssss.
0:13:58 > 0:14:00This is the Great Wall of China.
0:14:00 > 0:14:06Originally believed to stretch to an incredible 13,000 miles,
0:14:06 > 0:14:10this is easily the biggest defensive structure in the world.
0:14:10 > 0:14:12Meet BigDog -
0:14:12 > 0:14:15a prototype rough-terrain robot that walks, runs,
0:14:15 > 0:14:17climbs and carries heavy loads.
0:14:17 > 0:14:21The plan is that, one day, soldiers will use this robotic hound
0:14:21 > 0:14:23to carry equipment on the battlefield.
0:14:23 > 0:14:27Walkies! DOG BARKS
0:14:27 > 0:14:29No, this isn't the set of Star Wars.
0:14:29 > 0:14:33In fact, these fortified towers in the Thames Estuary off Kent
0:14:33 > 0:14:37were used to defend Britain from attack during World War II.
0:14:37 > 0:14:38Rusty.
0:14:39 > 0:14:42- We're in California! - Is that in America?
0:14:42 > 0:14:45You're very clever. And it's home to our final genius.
0:14:46 > 0:14:49Medieval castles and reinforced concrete bunkers
0:14:49 > 0:14:52were at the cutting edge of defensive engineering.
0:14:52 > 0:14:55Our third genius has come up with a way to give protection
0:14:55 > 0:14:58from things flying at us, which is what I need right now.
0:15:00 > 0:15:02No, not baseballs. Asteroids.
0:15:02 > 0:15:05Let's smash it out of the park for our next genius,
0:15:05 > 0:15:06Megan Bruck Syal.
0:15:06 > 0:15:08The one and only!
0:15:08 > 0:15:12Oh, hang on. What's going on here? Is this supposed to be me?
0:15:12 > 0:15:14And who the heck are you?
0:15:14 > 0:15:17Sorry, Megan. She's very rude, you know.
0:15:17 > 0:15:19Nice to meet you. A real-life genius!
0:15:19 > 0:15:21Come in here. Come and meet the other one.
0:15:21 > 0:15:22Oh, rubbish!
0:15:22 > 0:15:24Absolutely useless. Right, I've got a friend for you.
0:15:24 > 0:15:27- Oh, hi, Megan.- Hey. - Nice to meet you.- Nice to meet you.
0:15:27 > 0:15:29What is it about playing baseball, then,
0:15:29 > 0:15:30that ties in with your genius idea?
0:15:30 > 0:15:33Baseball is a really useful way of understanding the threat
0:15:33 > 0:15:34that we're under from asteroids.
0:15:34 > 0:15:38So, in the future, an asteroid might be coming right at the earth,
0:15:38 > 0:15:40just like the baseballs are coming right at you.
0:15:40 > 0:15:41Ah, that's the asteroid. Right.
0:15:41 > 0:15:44And we need a way to deflect the asteroid off course
0:15:44 > 0:15:46- from the earth, just like you're using the bat.- Aha.
0:15:46 > 0:15:49But that's not actually a real threat, is it -
0:15:49 > 0:15:50an asteroid hitting planet earth?
0:15:50 > 0:15:54Actually, there's many thousands of asteroids out there undiscovered,
0:15:54 > 0:15:57and some of them will be likely to hit us in the future.
0:15:57 > 0:15:59We just don't know when.
0:15:59 > 0:16:03NASA estimate nearly 15,000 asteroids can be classified
0:16:03 > 0:16:07as near-earth objects, but hardly any of those
0:16:07 > 0:16:09will actually make it all the way to earth.
0:16:09 > 0:16:13Most are small and burn up in the earth's upper atmosphere,
0:16:13 > 0:16:15creating shooting stars.
0:16:15 > 0:16:20But every once in a while, one comes a little too close for comfort.
0:16:20 > 0:16:26In 2013, this 20m-wide meteor exploded in the skies above Russia.
0:16:28 > 0:16:32This amazing footage from mobile phones and security cameras
0:16:32 > 0:16:35shows just how powerful the blast was.
0:16:37 > 0:16:40At this hi-tech US government facility,
0:16:40 > 0:16:44Megan and her colleagues are working to defend our planet
0:16:44 > 0:16:47against future threats from space.
0:16:47 > 0:16:49- Looks like a spaceship.- Yeah.
0:16:52 > 0:16:54Megan, we've been in some labs before,
0:16:54 > 0:16:56but this looks like the daddy of all labs.
0:16:56 > 0:16:57What goes on in here?
0:16:57 > 0:17:01We're hoping to learn more about how these asteroids will respond
0:17:01 > 0:17:04to the ways in which we're likely to try to deflect them.
0:17:04 > 0:17:06So, in here, we're using a laser.
0:17:06 > 0:17:09We fire that laser at the meteorite samples.
0:17:09 > 0:17:12We have some really sophisticated cameras and mirrors...
0:17:12 > 0:17:13- Yes.- ..lenses.
0:17:13 > 0:17:16They'll be looking in at the target as it's being zapped.
0:17:16 > 0:17:18We'll watch how that meteorite responds to the laser.
0:17:18 > 0:17:21So, let's say, in hundreds of thousands of years' time,
0:17:21 > 0:17:24a meteorite is coming towards earth, what would you do?
0:17:24 > 0:17:26So, if an asteroid really were going to threaten the earth,
0:17:26 > 0:17:28there's two main techniques we'd use.
0:17:28 > 0:17:30The first is called a kinetic impactor.
0:17:30 > 0:17:31It's very straightforward.
0:17:31 > 0:17:34- A spacecraft would just crash into it at high speeds...- What?!
0:17:34 > 0:17:36..dump all of its momentum into the asteroid
0:17:36 > 0:17:39so it would just be nudged off course with earth.
0:17:39 > 0:17:44Plan A - fire an unmanned rocket and knock the meteor off course.
0:17:46 > 0:17:48Second option -
0:17:48 > 0:17:50and we need to use this for somewhat larger asteroids
0:17:50 > 0:17:53or asteroids where we don't have a lot of warning time -
0:17:53 > 0:17:55we could use a nuclear explosion
0:17:55 > 0:17:59that would be deployed some distance from the surface of the asteroid,
0:17:59 > 0:18:00so we'd hopefully deflect it.
0:18:00 > 0:18:06Plan B - blow up a massive bomb and send the meteor flying.
0:18:06 > 0:18:08That's it. Get out of it!
0:18:08 > 0:18:11For your genius idea to protect planet earth
0:18:11 > 0:18:12from an asteroid attack...
0:18:12 > 0:18:15Megan Bruck Syal, you are an absolute genius.
0:18:15 > 0:18:18- You don't look like me. - YOU don't look like ME!
0:18:18 > 0:18:20- Oh.- Now, get out of my lab!
0:18:22 > 0:18:24From the medieval castle
0:18:24 > 0:18:28to the very latest in planet-saving technology...
0:18:28 > 0:18:31We've seen how some truly genius engineering
0:18:31 > 0:18:34has kept people safe from the threat of attack.
0:18:37 > 0:18:40Now then, we're going to have a go at building...
0:18:40 > 0:18:41And attempting to demolish.
0:18:41 > 0:18:43- ..our very own castle. - Cas-tle.- Caw-stle.
0:18:43 > 0:18:45And where better place to build a castle...
0:18:45 > 0:18:48- Caw-stle.- Cas-tle. ..than here at the seaside?!
0:18:53 > 0:18:55But if we're going to build a castle out of sand,
0:18:55 > 0:18:57then it needs to be big.
0:18:57 > 0:18:59REALLY big.
0:18:59 > 0:19:02And for that, we need the help of an expert.
0:19:02 > 0:19:03Not you.
0:19:03 > 0:19:04Ah, that's better.
0:19:04 > 0:19:08Meet professional sand sculptor Mark Anderson.
0:19:08 > 0:19:10He's built everything you can possibly imagine,
0:19:10 > 0:19:14and all out of sand taken straight from the local beach.
0:19:14 > 0:19:16Boo!
0:19:16 > 0:19:18I've got a monster build Genius challenge,
0:19:18 > 0:19:20which is to build a humongous sandcastle.
0:19:20 > 0:19:22- I'm going to flatten it. - Are you?- Squash it to the ground.
0:19:22 > 0:19:24You're not, cos I'm going to reinforce it.
0:19:24 > 0:19:26Nice and strong so you can't flatten it.
0:19:26 > 0:19:29- That's what you think.- Look, we need... I need some inspiration.
0:19:29 > 0:19:31- OK, well, let's go and have a look around.- Yeah.
0:19:31 > 0:19:33See if there's anything we can inspire you with.
0:19:33 > 0:19:34Then we'll go into the sandpit,
0:19:34 > 0:19:37make a mock-up and then see how we're going.
0:19:37 > 0:19:39Get to play sand castles! Amazing.
0:19:41 > 0:19:45'So, while I'm busy planning my castle...'
0:19:45 > 0:19:48- Is this the tallest one here? - It is, yeah. 5m.
0:19:48 > 0:19:51I'm working out how to reduce it to rubble.
0:19:51 > 0:19:54HE GRUNTS
0:19:54 > 0:19:55- So, just mix the sand with some water.- Yes.
0:19:55 > 0:19:57- Get a nice, big handful of that. - Dream job, this.
0:20:01 > 0:20:03So, you and your team are going to construct the real thing now.
0:20:03 > 0:20:05- We are.- And I'll come back later
0:20:05 > 0:20:07when you're nearly done and add the finishing touches.
0:20:13 > 0:20:16Many, many, many hours later,
0:20:16 > 0:20:20and at our beach building site, Mark and I are almost done.
0:20:23 > 0:20:25It's great round the front, but round the back,
0:20:25 > 0:20:27there's some tissue sticking out. What's this?
0:20:27 > 0:20:30Well, this is one of the ways of reinforcing concrete,
0:20:30 > 0:20:32so we thought we'd give it a go with the sand.
0:20:32 > 0:20:34So, we've learned all about reinforced concrete.
0:20:34 > 0:20:37This is reinforced sand, folks, right here. OK.
0:20:37 > 0:20:39I don't care how reinforced it's going to be
0:20:39 > 0:20:41cos I've got watermelons.
0:20:43 > 0:20:45I reckon it's going to take more than melons
0:20:45 > 0:20:47to knock this beauty down.
0:20:47 > 0:20:51James of Saint George would be proud.
0:20:51 > 0:20:55The castle wall is 2m tall and almost a metre thick,
0:20:55 > 0:21:00and safely behind it, my magnificent Trojan pig.
0:21:00 > 0:21:05In total, this truly monster build weighs more than 20 tonnes.
0:21:07 > 0:21:12Dick, you may take my castle, but you'll never take my pig!
0:21:14 > 0:21:16Here's how it's going to work.
0:21:16 > 0:21:19Mark and I - well, just Mark, really -
0:21:19 > 0:21:22has lovingly sculpted my Trojan sand pig.
0:21:22 > 0:21:26It's reinforced with layers of tissue paper
0:21:26 > 0:21:30and protected from frontal assault by a supersized sand wall,
0:21:30 > 0:21:32just like castles of old.
0:21:32 > 0:21:34Dickie has no chance.
0:21:34 > 0:21:36I wouldn't be so sure.
0:21:36 > 0:21:38Just wait till you see the awesome selection of weapons
0:21:38 > 0:21:41- I've got to choose from. - HE LAUGHS
0:21:42 > 0:21:44Let battle commence.
0:21:44 > 0:21:47Come on. Come and get my pig.
0:21:47 > 0:21:48'Anyone for tennis?'
0:21:49 > 0:21:50Speed up.
0:21:56 > 0:21:58Oh!
0:21:58 > 0:22:00Making a bit of damage. It's a good start.
0:22:00 > 0:22:02My castle's rock-solid.
0:22:04 > 0:22:06Ooh! I got the camera!
0:22:08 > 0:22:10It's advantage Dick.
0:22:13 > 0:22:15Rock-solid.
0:22:15 > 0:22:17Here he comes. Here he comes.
0:22:17 > 0:22:19Come on, then.
0:22:19 > 0:22:2170mph tennis balls -
0:22:21 > 0:22:24scary for me, but no problem for the wall.
0:22:24 > 0:22:27- I'm running out of balls!- Deuce.
0:22:27 > 0:22:31My castle is still intact, but what about my prized porker?
0:22:31 > 0:22:33My beautiful pig!
0:22:33 > 0:22:34It hit the swine on the backside,
0:22:34 > 0:22:38but the only other damage concerned - nothing.
0:22:38 > 0:22:40My pig is in place.
0:22:41 > 0:22:44Yes, I may have lost the battle, but I haven't lost the war.
0:22:44 > 0:22:46Slice of melon, Dom?
0:22:46 > 0:22:47It's melon time!
0:22:47 > 0:22:50This honeydew is coming to you.
0:22:50 > 0:22:52Oi!
0:22:52 > 0:22:54- That's my turret!- Yes!
0:22:54 > 0:22:56Oi, you put that honeydew away.
0:22:58 > 0:23:00- Yes!- Right in the window.
0:23:00 > 0:23:03These beauties are doing way more damage.
0:23:05 > 0:23:08Back of the net. Now for the pig.
0:23:08 > 0:23:10- Pig hitter!- No!
0:23:10 > 0:23:12Ooh!
0:23:12 > 0:23:15- Did that hit my pig? - It's a honeydew blitz.
0:23:17 > 0:23:21It's actually really tough to damage. Look. See?
0:23:21 > 0:23:23Did that hit my pig?
0:23:25 > 0:23:26No, it's not hit my pig.
0:23:26 > 0:23:28No more Mr Nice Guy.
0:23:28 > 0:23:30Right, time for a big one.
0:23:31 > 0:23:32Yes, yes...
0:23:32 > 0:23:36These watermelons are more than twice the weight of the honeydews.
0:23:36 > 0:23:37No.
0:23:37 > 0:23:41But my oinker has yet to take a direct hit.
0:23:43 > 0:23:45He's got a new technique, folks.
0:23:45 > 0:23:47Argh!
0:23:50 > 0:23:52Yeah!
0:23:52 > 0:23:54Get in!
0:23:54 > 0:23:56At last, I've found my range.
0:23:57 > 0:23:59That castle is firmly in my sights.
0:24:00 > 0:24:02Argh! Argh!
0:24:04 > 0:24:05Oh!
0:24:05 > 0:24:08But, alas, my watermelons can't weasel their way
0:24:08 > 0:24:11through Dom's defences. Time for a change of tack.
0:24:11 > 0:24:14ENGINE STARTS
0:24:19 > 0:24:22He's melting my castle. It's melting like it's made of wax.
0:24:22 > 0:24:25This high-pressure washer could strip paint off a shed...
0:24:25 > 0:24:26Pig next.
0:24:26 > 0:24:28..and it's really doing the trick.
0:24:28 > 0:24:30That wall is my first line of defence.
0:24:30 > 0:24:32As long as he doesn't get through it and attack my pig,
0:24:32 > 0:24:34I don't care what he does to the outside.
0:24:34 > 0:24:36Don't be so cocky. I'm going in.
0:24:45 > 0:24:49It's popped out the other side! My oinker's getting wet!
0:24:49 > 0:24:50Pig. I'm nearly at the pig.
0:24:50 > 0:24:52This is hogwash!
0:24:52 > 0:24:55I'm defending it! You can't get my pig wet!
0:24:57 > 0:25:00Argh! Right, I've had enough. It's not working.
0:25:00 > 0:25:03There's more on me than I'm destroying the castle.
0:25:03 > 0:25:05There's only one thing for it.
0:25:05 > 0:25:06Is he finished?
0:25:06 > 0:25:09That's it. Look at that! My pig's still intact.
0:25:09 > 0:25:11A little bit damp around the edges, but it doesn't matter.
0:25:11 > 0:25:15I have got an indestructible hog!
0:25:15 > 0:25:17You have left me no option.
0:25:17 > 0:25:21You, sir, and your pig have brought this on yourselves.
0:25:21 > 0:25:24It's a thing of beauty. ENGINE APPROACHES
0:25:29 > 0:25:32Pig, we're coming to get you.
0:25:32 > 0:25:36This is a British Scorpion tank - eight tonnes of tracked fury.
0:25:36 > 0:25:39You don't need melons. You don't need tennis balls.
0:25:39 > 0:25:42You just need a tank.
0:25:42 > 0:25:45It's designed to move across virtually any terrain,
0:25:45 > 0:25:47sand included.
0:25:47 > 0:25:49You leave my castle alone! Don't you...
0:25:49 > 0:25:52- Don't. Don't.- Here we go.
0:25:52 > 0:25:55Don't you dare demolish this!
0:25:57 > 0:25:58Whoa!
0:25:59 > 0:26:01Get in!
0:26:01 > 0:26:02Stop!
0:26:05 > 0:26:07What have you done to my castle?
0:26:07 > 0:26:08That's one corner gone.
0:26:08 > 0:26:11It's smashed to pieces!
0:26:11 > 0:26:13That's how you demolish a castle.
0:26:15 > 0:26:17Ruined! Ruined!
0:26:17 > 0:26:19Well, that's the castle accounted for.
0:26:19 > 0:26:22Don't you worry. Everything's fine. You'll be fine.
0:26:23 > 0:26:25Now your porker's for the chop.
0:26:27 > 0:26:30Here we go. Come on, pig.
0:26:30 > 0:26:32Leave our tank alone.
0:26:32 > 0:26:35Not the pig. Not the pig. Don't you dare.
0:26:35 > 0:26:38- Goodbye, pig.- Leave my pig alone. - Goodbye, pig.
0:26:38 > 0:26:41Bye, pig. Yeah!
0:26:41 > 0:26:44Hey-hey! Whay!
0:26:44 > 0:26:45You've knocked his head off!
0:26:47 > 0:26:49He's got no head.
0:26:50 > 0:26:52- No!- Yeah!
0:26:56 > 0:26:58That's the pig down, ladies and gentlemen.
0:26:58 > 0:27:00Mission complete.
0:27:01 > 0:27:02'Victory.'
0:27:02 > 0:27:06Even my super-strong swine is no match for a tank.
0:27:07 > 0:27:09He's made a right pig's ear of that one, eh?
0:27:10 > 0:27:14Well, better go and get a bucket and spade and start again.
0:27:19 > 0:27:21We've seen how some nifty engineering has come up
0:27:21 > 0:27:23with brilliant defensive ideas.
0:27:23 > 0:27:25Thanks to these three geniuses,
0:27:25 > 0:27:27we are now relatively safe from the threat of attack.
0:27:27 > 0:27:29Unless your house is built out of sand
0:27:29 > 0:27:31and it's being driven over by a tank.
0:27:31 > 0:27:34James of Saint George, Monier and Bruck Syal,
0:27:34 > 0:27:36you are all absolute genius.
0:27:36 > 0:27:39Smashing work, fellas. Now then, let's have a paddle.
0:27:55 > 0:27:56He's loving it.
0:27:56 > 0:27:58I hate it!