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00:00Ah, the Alps. Stunning scenery. Chocolate box houses.
00:10How much more alpine can that get?
00:14Mountain goats.
00:18Oh, and one of the worst traffic jams in Europe.
00:23This is the Brenner Pass, one of the most vital road and rail routes between Northern and Southern Europe.
00:29Food, clothes, new cars, washing machines, fridges, socks. Many of the things we use and take for granted come by road or rail via this route through the middle of Europe.
00:41It's chaos.
00:44The solution?
00:47Ease the bottleneck by building a giant rail tunnel. This is one of the biggest engineering projects the world has ever seen.
00:55And it's two kilometers underground beneath one of Europe's biggest mountain ranges.
01:02It'll take 20 years to do it. It is that ambitious. It's really, really big. And really, really dangerous.
01:13Here I go.
01:14I'm Richard Hammond.
01:16Hello.
01:17And I'm on a mission to explore the really, really big.
01:21Awesome!
01:22Top ten list of insane things I've ever been involved in doing. This is number one.
01:27And yes, I know, everything seems big to me.
01:30Am I climbing into an engine? I feel like I've been stroked.
01:34I'll uncover the incredible ways engineers have supersized our world.
01:39I'm not sure it's supposed to be this close.
01:41I looked over my shoulder. I shouldn't have done that.
01:44Reveal that sometimes it's the tiny things that make the Titanic possible.
01:49Stealing their power! Ha ha ha!
01:52I could not do this for a job.
01:54And meet the heroes who design, build, and live big.
02:01If I do it wrong, are we all blown to pieces?
02:04Maybe.
02:05Maybe.
02:19I never thought one day I'd be riding deep down into the bowels of the earth,
02:24underneath the Alps.
02:26Oh, I'm loving this!
02:28This is not just the story of a very, very long tunnel.
02:32It's the story of one of the most ambitious engineering projects ever attempted by mankind.
02:38Sure, it'll cost £7 billion and take 20 years to complete,
02:43but when it's done, they'll have built the impossible through the impossible.
02:47I've got 15 kilometres to go before I get to the business end of this tunnel.
02:52I don't know, there's something primitive about this.
02:55Mankind's tunnelling through the earth.
02:58I'm on my way to see one of the world's biggest tunnelling machines cutting its way through a mountain on the Italian side of the Alps.
03:11All tunnel boring machines, or TBMs, are given names, and this one is Flavia.
03:17And she isn't just a boring machine, she's a moving factory.
03:24Weighing a monster 3,000 tonnes, Flavia is the length of four Olympic-sized swimming pools.
03:34All of this, as far as I can see, is one machine.
03:37Up at the front, the cutting head is chewing its way through the ancient rocks of the Alps,
03:42and this whole tail follows of it, all 200 metres.
03:49At the front, the cutting head is 11 metres tall, more than twice the height of a London bus.
03:56Flavia can grind her way through 15 metres of mountain rock every single day.
04:01And operations manager Giorgio Malicelli is taking me to the front to show me how.
04:08Giorgio, this, then, is the cutting head?
04:11This is the cutting head.
04:12Yeah.
04:13So these are...?
04:14These are the cutter discs, 19-inch.
04:16Which one?
04:17We got 64 of them on the cutter head.
04:20Unlike the machines I dreamt of as a kid that sort of come to a point like a big drill,
04:26this doesn't drill.
04:28No, it crushes.
04:31The 64 steel cutter discs score four millimetres into the rock face,
04:37which then cracks and fractures and falls away.
04:40As it rotates, the cutter head is pushed forwards by six powerful hydraulic arms,
04:47pressing the rock face with the force of 15 40-ton trucks.
04:52What a machine. They are quite expensive.
04:56Yeah.
04:57Talking, we are in the 20 million range for a machine like this.
05:00I'm always on the lookout for the small things that make the big possible,
05:04and, well, here they are. These are the cutting wheels. These are used ones.
05:07And for this whole enterprise, all of this effort, all of these humans and machines,
05:13this is the interface between man and mantin.
05:16This is where it's chewed its way through the rock.
05:18It will be taken away and recycled.
05:21I say they're small things. To be fair, they each weigh more than me,
05:25but in comparison, they're tiny, but crucial.
05:28What's amazing about Flavia is she is a multitasker.
05:37Whilst her teeth are grinding away at the business end,
05:40just behind the cutter head, she's also laying her own tunnel walls,
05:45placing a series of nine-ton concrete slabs onto the freshly cut rock,
05:50leaving a perfectly lined circular tunnel at a speed of one metre an hour.
05:55Flavia is one of three tunnel boring machines involved in this extraordinary $9 billion construction,
06:03which started in 2008 and won't end until 2026.
06:11When completed, two main rail tunnels will join Forteza in Italy to Innsbruck in Austria,
06:17each a record-breaking 55 kilometres long.
06:22One tunnel will take trains north, the other south.
06:27All along the route will be a further 200 connecting access and maintenance tunnels.
06:33The finished tunnels will carry nearly a million tonnes of freight on 320 trains a day.
06:39But the most ambitious part of building the longest rail tunnel in the world lies in where they're trying to do it.
06:47This particular stretch of tunnel runs through the peri-adreatic ceiling,
06:52the point where two tectonic plates come together.
06:55You might have heard of them.
06:57Behind me is Africa. Up ahead of me, that's Europe.
07:00To put it simply, this tunnel is being built through two of the Earth's enormous moving parts.
07:10And when those parts move, stuff happens. The Earth moves.
07:16I think I'll tread carefully from here on.
07:18The collision of two continents created the Alps mountain range.
07:25But it also pushed up what would normally be horizontal layers of rock, creating unpredictable vertical layers.
07:32That means man and machine have no way of knowing if the rock is too hard or too soft to safely drill through before they hit it.
07:41But fortunately, they've come up with an ingenious solution to solve that one.
07:47And it is to build another tunnel.
07:51The quality of the rock is tested by this exploratory tunnel, 12 metres below and 20 metres ahead of the main tunnel project.
07:59And it's being bored by Flavia's little brother, Gunther.
08:02Geologist Jeremy Dijon de Labatti heads the team investigating the state of the mountain rock.
08:12So where are we going?
08:14To the south, to Italy.
08:17Well, I don't mean the whole tunnel. I meant now.
08:20Welcome to my lab.
08:22So what do you do down here?
08:23We take samples, we look at the geology, and we look at if there are faults or joints, you know, who could be a problem for the drilling.
08:33So this is the sort of rock we're on now?
08:35Yeah. You see the foliation.
08:37As a geologist myself, I'll define it as stripy. Is it good for going through the TBM?
08:44Of course, yeah. You can drill really good.
08:46What's the worst thing you can find if you've just done some more?
08:48If there's a lot of water, if there's water, that's a big problem, yeah.
08:56And what would happen?
08:58We had to close down and then bypass that.
09:01The decisions made down here, then, as you take the samples and examine what you've just drilled through,
09:07there are tens of millions of euros, dollars.
09:11Of course, yeah. Of course.
09:13With so much at stake, Jeremy and his crew of 12 tunnelers are charged with going where no man has gone before,
09:22which makes TBM Gunter a kind of subterranean starship enterprise.
09:27And at the helm, right behind the cutter head, is Captain Kirk.
09:32Although, in this case, he's engineer Lars Napstein.
09:35Yeah, the TBM is now taking up progress.
09:38Is that massive hole not a problem?
09:41Yeah, that's kind of a massive hole. I mean, we had bigger ones, but as you see, it's a nice place to stay.
09:48Okay, and that's a good thing that just happened there? I don't need to be alarmed.
09:53It's common.
09:54But it's crumbling. It's caving in as we go.
09:58Yeah, I mean, it's a dirty business. It's dangerous, but it's also really impressive.
10:05I'm a little bit scared, if I'm honest, but I'm going to hide that because they're all very...
10:11It's bloody terrifying.
10:13Right now, this TBM is chewing its way through the rocks, under the Alps, going where nobody has ever, ever been before.
10:21All this has already fallen, because it's, look at that, we're going to just make bits of it flaking away.
10:29And that's what they're drilling through.
10:34I won't stand there.
10:36What's this doing?
10:37He's pushing up right now the steel bowl.
10:41So that's the brace.
10:42Yeah, it supports the rock and these steel mats that they won't fall onto us.
10:47And this is the only thing that protects us now from being crushed and smashed to pieces.
10:53I can feel through my feet.
10:55It's mind-blowing.
10:56It's amongst the most exciting things I've ever been involved in.
10:59Now, these obviously are more fixing rods to fix this steel arch, to hold the mesh up, to stop bits falling down.
11:10Obviously, this will not stop a mountain falling on us.
11:13I am kind of conscious right now that there's over a kilometre of rock on top of me.
11:28Water!
11:30Water!
11:31I don't like that!
11:32Am I the only one who saw the water and didn't realise it was for lubricating the drill and thought,
11:44oh, we've hit the mains or something?
11:46I panicked.
11:48I thought, we've hit an underground river, we're all going to die.
11:52Next.
11:54I wind up in a rather dangerous situation.
11:57If I do it wrong, are we all blown to pieces?
12:02Maybe.
12:03Turn around, turn around.
12:21Right in the heart of Europe is one of the biggest and longest mountain ranges, the Alps.
12:28And I'm underneath it, exploring one of the world's biggest and most expensive engineering projects, the Brenner Tunnel.
12:38It's also one of the most dangerous.
12:47Fire, rock falls, floods.
12:49If you're two kilometres underground, working beneath millions of tonnes of rock, you need to know what to do in an emergency.
12:59And engineer Giacomo Zamola needs to show me a room he hopes we won't have to use.
13:03Oh, wow.
13:06If it all goes wrong, this is where you come?
13:10Yes, this is our rescue room.
13:13Right.
13:15So then we come in here.
13:17Yes, if something goes wrong, like an accident or a fire.
13:21So is this reinforced?
13:23Is it strong if there's a cave in?
13:25Yes, this is made by steel.
13:27It's like a submarine.
13:29So we come rushing in here.
13:30Oh, no, there's a bit of cave in.
13:32What do we have in here to look after us?
13:34Do we have oxygen?
13:35Yes, we have here our tanks of oxygen, and also we have a line of hair, pressure hair, that comes from outside.
13:44I would have had that half of it full of gin, playing cards along here, big widescreen TV, a week's worth of oxygen, and I'd sling you all out now and I'd have it to myself.
13:57We perfectly, yeah.
14:00The oxygen is enough for 32 people and just for 24 hours.
14:06If something goes wrong, yes.
14:09It's not a positive idea.
14:11Right, 24 hours.
14:12So we're a long way from the surface.
14:14Yes.
14:15Suddenly it makes it all seem very real.
14:19How dangerous this is.
14:20Yes.
14:21Right now, the whole tunnel isn't connected.
14:28An Italian team and an Austrian team are excavating their own sections of tunnel beneath their own sides of the mountain range.
14:36The plan is to construct separate segments along the route of the tunnel, then gradually, over the remaining eight years, connect them together to make the completed tunnel.
14:52And each segment of tunnel also has its own maintenance tunnels and access tunnels.
14:57There are tunnels between tunnels and tunnels leading off from tunnels to get to other tunnels.
15:03And because they all look the same, I have no idea where I am, except that I'm somewhere beneath Italy, in a tunnel.
15:11Just have a thought, I am thousands of metres under a mountain range, in the dark, in a tunnel, plunging into the bowels of the earth.
15:25If Gandalf and a load of hobbits come the other way, I shan't be surprised.
15:30If they're pursued by orcs on scooters, I'll be furious. I hate scooters.
15:34What I need to do now is get to a maintenance tunnel being dug on the Austrian side of the Alps.
15:42So I'm leaving this tunnel to track around to the next bit.
15:46And I get to see the sun!
15:49Oh!
15:51Oh, that's warm on my legs! That is...
15:55That's just epic!
15:57Around 80 million tonnes of freight travels across the Alps every year,
16:04almost half of it going through a single congested pass between Italy and Austria.
16:10Europe hopes this new freight rail tunnel, two kilometres beneath the Alps,
16:15will carry a million tonnes of freight a year, taking thousands of lorries off the roads
16:20and transforming the way goods travel through the continent.
16:23This show is about a tunnel that's here to alleviate the terrible traffic congestion through the pinch points in the Alps.
16:33Well, I'm stuck in traffic.
16:35It's ironic, isn't it?
16:39Yeah, I really...
16:41Oh, it's all...
16:43Oh, hang on a minute, I can't hold back, I can't hold back!
16:46That was doing good, I've got to go!
16:48Unlike the main rail tunnel bored by Flavia, maintenance and access tunnels like these are created the old-fashioned way,
17:00which means I get to blow something up.
17:03But first, explosives engineer Hubert Hoffman is going to show me how to drill the holes in the rock to put the explosives in.
17:12My friend is going to help me have a go, I've got a hundred holes to make here to blast this face.
17:18When, oh, he's behind it! Oh God! That could be horrible. Okay.
17:23According to Hubert, blasting is an exact science.
17:26To create a perfect arch, the explosives have to be placed in a precise pattern and detonated at precise intervals.
17:36This is the plan of the explosives that are going to be put in this face to blow it.
17:41And they all have to be in the right place and at the right angle, that's what these long lines are for.
17:46Where do I go? Which one? Down here? That one. That one, yeah?
17:49I'm now going to start the drill. One touch.
17:57I've been straight in. That is now drilling. We can see here how deep it's going.
18:08And that's retreated. So that's that one done. And now we're going straight in.
18:14Oh, I'm getting this. In it goes.
18:16The idea is that each explosive will detonate a fraction of a second before the one in the hole next to it.
18:27So the blasted rock moves into the space left by the previous explosion.
18:32And this pattern of holes should create a perfect arch.
18:35Project manager Michael Kronteiler seems perfectly happy for me to handle some explosives.
18:50Hasn't he seen any of my shows?
18:51I'm standing next to a man with a handful of explosives.
18:55Yeah.
18:56What kind of explosive is it?
18:58It's a slurry cartridge. Yeah. It weights 800 grams.
19:02Yeah. So we are charging approximately 2kg per borehole.
19:06And now it's your turn to do it.
19:09What, to charge it? Sure.
19:11Really?
19:12We'll just put in the detonator and then you will charge the hole.
19:17What is it?
19:18It's called slurry.
19:19What's it?
19:20It's like a gel. It's very special.
19:22Could you take this off me now because it's explosive?
19:25I can hit you with that.
19:26I don't think you should.
19:28No, just put it inside.
19:31Oh, that's high tech.
19:32Yeah.
19:33What do I do with that?
19:36So, now take the stick and just push it in.
19:41If I do it wrong, are we all blown to pieces?
19:44Maybe.
19:45Okay. Thank you so much.
19:47Right. Well, literally, this is like being in a cowboy movie, isn't it?
19:50Do it. Just push it in.
19:55How do I know when to stop?
19:57Push, push, push, push.
19:58Am I too delicate-handed to be in?
20:02Push, push.
20:04That's pushed.
20:06That's definitely in.
20:07Don't be in.
20:09Oh, don't be ridiculous. It's explosive!
20:13There are now a hundred of these sticks placed deep into the rock face.
20:18That's 200 kilograms of explosives,
20:21the same amount they packed into mines to sink battleships in the First World War,
20:26loaded and ready to blow.
20:29Time to retreat to a safe place next to the detonator,
20:33which, alarmingly, is just around the corner.
20:37And even more alarmingly,
20:39looks like something salvaged from the First World War.
20:42Okay, wind it until you see the red light.
20:45Yeah.
20:46Then two or three turns more,
20:48and then he will say, thank you very much. Boom.
20:50This feels like something out of a cartoon.
20:54But if it goes wrong, no-one's laughing.
20:58Yeah, I'm a bit scared!
21:00That's the blasting machine.
21:02Yeah. Okay.
21:03And you're going to let me do this?
21:04Sure.
21:05Come here.
21:07First thing is, you have to charge the machine, okay?
21:09That means you turn that lever until you can see the red light here.
21:13Yeah.
21:14Okay, if you see the red light, two or three turns more.
21:16Yeah.
21:17That means the machine is fully charged.
21:20Yeah.
21:21And that's the magic button.
21:22Right.
21:23And I'm going to be allowed to do this.
21:24Yes.
21:25This isn't a dummy, this is the actual one.
21:26Yes.
21:27One hand there.
21:28I can't believe this is old school.
21:30Right.
21:31Do I want...
21:35Well, I am quite scared.
21:36Turn, turn.
21:37Fast, fast, fast, fast, fast, fast, fast.
21:42More, more, more, more, more, more, more.
21:44Okay, okay, okay.
21:45Okay.
21:46Pushing the button.
21:47Told to open my mouth.
22:06Well done.
22:08Glück auf.
22:10Glück auf.
22:11What does glück auf mean?
22:12Glück auf.
22:14That's a minor language.
22:15Is it?
22:16Yeah.
22:17Glück auf.
22:18That was epic.
22:20Glück auf.
22:21Yeah.
22:22So?
22:23You feel it, don't you?
22:24Yeah.
22:25You are shaking, man.
22:26Yeah, no, absolutely.
22:27Do you feel that?
22:28That is properly thrilling.
22:29Yeah.
22:30I thought I'd be playing it cool, but wow.
22:33That was something else.
22:34Yeah.
22:35So this is what we've done?
22:40Exactly.
22:41Are we okay to go in here?
22:43Sure.
22:44This is just perfect.
22:45Perfect.
22:46Oh, I see.
22:47What is very important is the profile, so it's very accurate, no overbreaks, yeah?
22:54Well, it's already curved, it's already round.
22:57Yeah, exactly.
22:58The most important thing is the face.
23:00It's perfectly vertical, yeah, no outbreaks, nothing.
23:04So it's a perfect face.
23:05So when you see one like that, you know we're good.
23:09Richard Hammond was here.
23:10I did that.
23:11I did that bit.
23:12Push the button.
23:13I'm very happy for you.
23:14Perfect job.
23:15I'm very happy for you.
23:16If you quit your current job, just come here.
23:18There's a role for me.
23:19Good.
23:20Do I get my own company torch?
23:21I'll do it.
23:22That's freshly minted.
23:23Nobody's ever stood where we've just stood.
23:29Next, I get a taste of what we're tunnelling through.
23:34Does it taste good?
23:35What?
23:36And I'm in trouble again.
23:37Amanda!
23:38What have you done?
23:40Oops.
23:41Once again, making my mark on this project.
23:45Unless it goes wrong, then it wasn't me.
23:47So far, on my journey to discover how you build one of the world's longest rail tunnels,
24:01under some of Europe's biggest mountains, I've flown up a tunnel wall, seen Flavia,
24:08the super-sized tunnelling machine.
24:10Oh, it's gigantic.
24:12And met her terrifying brother, Gunter.
24:15It's crumbling.
24:16It's caving in as we go.
24:18The scale and ambition of engineering here is off the charts.
24:26I'm still absolutely buzzing and pumped with adrenaline from that blasting.
24:30Just needed to know that.
24:38It's weird to think, in a pretty unspoiled alpine vid is like this, hundreds of meters below,
24:45where I've just been.
24:47Huge, great monstrous machines chewing their way through solid rock.
24:52Imagine the noise and fury going on below.
24:56I can't get that racket out of my mind.
24:59Having enjoyed my time with the Austrian tunnelers, I'm now heading back to Italy,
25:04to the place where the tunnel will surface and join up with Italy's existing rail network,
25:09to find out more about a massive problem they're battling.
25:16Water, the arch enemy of tunnel building.
25:19216 billion cubic meters of the stuff runs through the Alps every single day
25:25and engineers are having to work hard to keep it at bay.
25:29This is where the tunnel starts.
25:34So it's the point where the existing rail lines must meet the new ones that go down into the tunnel.
25:39That's difficult.
25:41And then just to make sure that the engineers here don't get, you know, bored with it all being too easy,
25:47there's a river thrown into the mountains, because all of this happens just beneath it.
25:52On either side of Italy's Iscara River, engineers have had to build four gigantic vertical access holes
26:02to help build the main freight tunnel under the river.
26:05Because here, the finished tunnel will be only four meters beneath the riverbed.
26:10When the snow melts, it can turn the river into a raging torrent, and these four access tunnels may flood.
26:20Which makes this one of the most dangerous sites in the whole project.
26:24Water anywhere in the tunnel walls is the most likely cause of cave-ins.
26:29So when you're this close to a raging river, to keep it out, you've got to go big.
26:38Gentlemen.
26:44Safe.
26:46This is Mauro, this is Vincenzo, and together we're going up to the roof of this stretch of tunnel
26:52to carry out what looks like a simple task, but it is essential.
26:57Best thing, I'm doing it!
27:00Oh, yeah.
27:02Once again, making my mark on this project.
27:04Unless it goes wrong, then it wasn't me.
27:07This is the PVC lining that keeps water away from the tunnel.
27:11That's about more than comfort and convenience.
27:13It's absolutely crucial.
27:15All this technology, all this incredible engineering,
27:18and this membrane here is the difference between success and disaster.
27:23Without it, it doesn't work.
27:25All this technology, all this brilliant engineering,
27:28and this, well, it's the last sort of thing you put under some gravel at home.
27:35It might look like a deflated bouncy castle,
27:38but every square meter of this reinforced plastic
27:41can take the weight of about 12 African elephants.
27:46Thankfully, the chance of elephants coming down here is pretty slim.
27:51Not impossible, but slim.
27:53Each three-meter strip has to be joined to the next,
27:56using a plastic welder to create one seamless watertight sheet.
28:01This tiny welder, that's the machine, by the way, not me,
28:06makes the huge job of waterproofing the massive walls of this tunnel possible.
28:10So it moves itself, but you have to keep it straight, and then you encounter this.
28:20This looks like such a simple task, and it is.
28:22But if I get it wrong, there could be a leak, and this stretch of tunnel could be compromised.
28:28It's absolutely terrifying.
28:31If there's a little gap in there, water comes in,
28:35they'll see a stain on this bit of wall,
28:37and somebody will go, Amanda, what have you done?
28:43Because this section of the tunnel will be so close to the riverbed,
28:47it's not solid rock that they'll be excavating.
28:50It's water-filled soil. In other words, sludge.
28:56And you can't dig a tunnel through sludge, can you?
29:01Maurizio, this looks terrifying.
29:03It's not terrifying.
29:04It is.
29:05It's pretty easy.
29:06Is this safe?
29:07Come in.
29:08Oh, this is nice.
29:09Geotechnical engineer Maurizio Ferreiro has landed tunneling's toughest gig.
29:14Your lift's not five-star.
29:16Well, it is five-star. It's very nice.
29:18Does it stop gently?
29:19You will feel now in a few seconds.
29:21OK.
29:22It's going to be a gentle halt.
29:23Oh, yeah.
29:24Yeah.
29:25Absolutely gently.
29:27Maurizio's job is to fight the element of water.
29:30It's on his shoulders to somehow turn sludge into something they can excavate.
29:36Everybody else is building tunnels, and you've built an amphitheatre.
29:39It's beautiful.
29:40It's lovely, but it's not what you want.
29:42Don't you like this?
29:43We need to perform a number of preparatory work
29:47below the level of the rivers.
29:50We have to do the artificial ground freezing under the Isarco River.
29:55You said ground freezing?
29:57Yeah.
29:58In the soil, we have some water.
30:00We insert some special probes inside the ground.
30:05In this probe, a proper liquid, that is liquid nitrogen.
30:10Freezing.
30:11We are going to freeze the soil.
30:14We are going to freeze the water that is within the soil.
30:18So we will be able to excavate within the frozen soil.
30:24So you freeze the soil, and you can quickly dig through it while it's firm.
30:29Yeah.
30:30We quickly dig, and we do the final lining, and then the tunnel will be completed.
30:36Right.
30:37Yeah.
30:38Brilliant.
30:39Brilliant.
30:40Totally brilliant.
30:41If it works, it sounds...
30:43Of course it works.
30:44Of course it does.
30:45Yeah.
30:46Yeah.
30:47It sounds completely crazy.
30:48So this is a kind of environmental solution.
30:52Otherwise, we have had to shift the river.
30:55Obviously.
30:56And that is a mess.
30:59Why did you get stuck with this one and not one of these?
31:03With this job?
31:04Yeah.
31:05Because I'm a lucky guy.
31:07Oh, yeah.
31:08I'm a technical engineer.
31:10So, I mean, this kind of site is a kind of paradise for the guy who do my kind of job.
31:18And on this scale?
31:19Exactly.
31:20How often in a career do you get to do it?
31:21This is extremely big.
31:22Yeah, yeah, yeah, yeah.
31:23It takes an incredible 2,000 litres of liquid nitrogen to freeze just one cubic metre of soil,
31:33making this an enormous and expensive undertaking.
31:37And it's hard to imagine how it could work.
31:40Bring on the melted gelato.
31:42I just want to look a bit more into this freezing the ground business.
31:46So, the ground around here is a bit like this.
31:48It's sludgy and sloppy.
31:50It's got bits and lumps in it.
31:52They come and try and drill it and it doesn't work.
31:56As fast as you drill it, it fills in behind it.
31:58However, you take this exact same sludge and freeze it, as I have done here,
32:02and as they're going to do with liquid nitrogen.
32:04All of a sudden, apply your drill.
32:06I'm tunneling through.
32:08I am mining.
32:09And hang on a second.
32:11Yep.
32:12I've made myself a tunnel through it.
32:14Mind you, it does taste good.
32:17What?
32:18Only in Italy could a massive engineering solution be inspired by ice cream.
32:28And now I'm heading back to the exploratory tunnel that Gunter and I dug out yesterday,
32:41because apparently I've left the job half-finished.
32:44Oh, my God.
32:45Oh, oh, it's gone wrong.
32:46It's gone the wrong way.
32:47Help!
32:48Help!
32:49Help!
32:50Help!
32:51Help!
32:52It's gone the wrong way.
32:53It won't go any further that way.
32:55They don't lay concrete slabs in the exploration tunnel.
32:56Instead, they shotcrete the tunnel wall.
32:57What's coming out of here at four times the speed of a firefighter's hose is a mix of concrete and small metal shards.
33:14These tiny shards strengthen the concrete, stabilising the excavated tunnel quickly, making it safe to work in.
33:22But it's not an easy job.
33:25And as the particles come back, it creates a solid surface.
33:29The impact as it hits the wall, makes it...
33:32Oh, my God!
33:34It is like plastering or spray painting.
33:38It's a three-dimensional spray, and it's bloody hard.
33:41Could you turn the concrete off?
33:44Yeah, I may have made a bit of a log in there.
33:51There are some things you can have a go at and just kind of do immediately.
33:56Shotcreting the newly excavated walls of a tunnel turns out not to be one of them.
34:02Might need to get rid of that.
34:09As a reward for my excellent handiwork, they're going to trust me with one of their service vehicles.
34:16They've told me I can drive it out again, which is going to be one heck of a piece of reversing,
34:20because I've got 20 centimetres either side.
34:22But I'm rather pleased they trust me.
34:24So this is like the control.
34:27Well, I'm only going to go for...
34:28Oh, wait a minute.
34:29Hello.
34:30No, that's...
34:31Oh.
34:32Oh, right.
34:33Oh, I see.
34:34Oh.
34:35Oh, funny.
34:36Hang on.
34:37I'm not even driving, am I?
34:39Funny.
34:40Yeah, you take your entertainment where you find it.
34:43A kilometre underground.
34:49Next.
34:50Welcome.
34:51You've just joined me on underground truckers.
34:53At last, I get to drive a very big truck.
34:57Ooh.
34:58Through a very small tunnel.
35:00This looks narrow.
35:03It works.
35:04Driving the big truck.
35:06I'm exploring one of the biggest and most ambitious engineering projects Europe has ever seen.
35:25Well, actually, can't see, because it's happening two kilometres under the Alps.
35:30Boring the longest rail tunnel in the world involves some enormous industrial engineering,
35:39using enormous machinery.
35:42But it also creates an enormous and rather messy problem.
35:47It's estimated that this project will generate 21 million cubic metres of rubble,
35:54which is hard to get your head around.
35:56Put it this way.
35:57That's enough to turn an area the size of Greater London into a gravel driveway one centimetre thick
36:04and still have enough left to do half of New York City.
36:09So, what do they do with that amount of rubble?
36:13The answer is...
36:15Cut a massive cavern out of the rock and build the world's biggest purpose-made subterranean cement factory.
36:22This place is huge.
36:24Every day, hundreds of tonnes of rubble are transported along 40 kilometres of conveyor belts,
36:31here to be turned into cement.
36:35This is a perfect piece of recycling.
36:38Excavate rock to make tunnels, bring those rocks to a processing plant underground,
36:44and turn it into concrete to line those tunnels.
36:47Everybody wins!
36:48But cement only uses 25% of all the rubble, so where does the rest go?
37:00To find out, I've been given a load of rubble, a massive truck, and a mission to go back up to the surface and get rid of it.
37:09I'm doing this on my own. There isn't a driver in here who's worried I might crash his truck.
37:17There is.
37:18Right, power.
37:19It works.
37:20Drive the big truck.
37:21Ooh.
37:22This looks narrow.
37:23Is it okay?
37:24Is it all right?
37:25Are you sure?
37:26Every single day, a fleet of megatrucks like this one make 140 journeys up to the surface, carrying, in total, 3,500 tonnes of tunnel trash.
37:34That's rubble the weight of a Statue of Liberty every week.
37:52There might be a whole series in this.
37:55Welcome.
37:56You've just joined me on Underground Truckers.
37:58I'm hundreds of metres beneath the Alps.
38:03Everywhere along all of these tunnels down here, you see these huge plastic tubes.
38:09They're for ventilation, and there are pumps dotted about, pushing huge volumes of air down them, and it's a good job they are.
38:16Because without that air, there wouldn't be enough oxygen down here to keep us alive.
38:20Oh, there it is, the light at the end of the tunnel, the dawn of a new day, and the start of a new segment in this show.
38:34Left or right?
38:35This is the Pedaster Valley, Austria.
38:45And right now, it's not looking its best, because it's currently the biggest dumping ground in all of Europe.
38:55Over half of all the rubble generated from this stretch of tunnel is being ticked here.
39:00And just look at it.
39:05What would Julie Andrews say?
39:09I'm hoping that my best friend Michael has got some answers.
39:13And this is where all the rubble comes.
39:16Yeah, all the material out of the tunnels will be stored here.
39:19And there's a lot of them.
39:21It's in total more than seven million cubic metres of material.
39:25And you can't just dump it in a van.
39:27Exactly. It's not allowed to dump material.
39:30So, if you can't just dump it, what do you do with enough tunnel rubbish to build seven Empire State buildings?
39:39Michael is a man with a very big plan.
39:42This natural V-shaped valley is slowly being transformed into a U-shape.
39:52The engineers are depositing rubble onto the valley floor in thin 60-centimeter compacted layers.
39:59It's going to take ten years to build it up, landscape it, reroute rivers and reintroduce native plants and wildlife.
40:09You're looking at the biggest garden makeover in history.
40:13So, this is gardening on a geological scale.
40:20How high is it going to be? Where would we be when it's finished?
40:23Around 140 metres higher than what you can see now.
40:28Oh, it's gigantic.
40:29Yeah.
40:30I mean, that's up there somewhere.
40:32Exactly.
40:33One of the biggest issues is infiltration of water, because you could create a big landslide.
40:39That's the next town, a very small town.
40:42They'd be very across.
40:43Yeah.
40:44So, how do you stop it going down there?
40:46We have a very huge drainage system containing all the water, which comes from infiltration from the surface.
40:55Engineers built a concrete drainage tunnel network inside the new compacted valley floor,
41:02to channel water out and keep one of the biggest rubble deposits in the world stable.
41:07So, you've got to control the water as it lands on this newly built valley when you've finished it,
41:11to make sure it doesn't transport the whole thing down there in a landslide and there's a disaster.
41:15You're right.
41:16As well as managing these massive challenges, Michael also needs to keep an eye on the tiny details.
41:23Did you have to move orchids here?
41:25Sure.
41:26So, you had to, specific little orchids and bats as well were an issue.
41:30Correct.
41:31Wait a minute.
41:32You've got one team of engineers who are down there doing all the heroic tunneling stuff
41:36and blasting rock and going where no person has ever gone before.
41:40And then all the ones up here, they're just like, I don't want to do the gardening.
41:43I want to do the heroic underground stuff.
41:45Sure.
41:46Which would they rather be, down there or up there?
41:48Want a tunneller, always a tunneller.
41:51So, really, they belong down there.
41:52It's gardening.
41:53You know what I mean?
41:54It really is a reminder coming out here though, where you're doing this and why.
41:59Actually, the roads over there.
42:02So, to free up and to avoid congestion in the beautiful Alps, you're all down there blasting
42:08and tunneling and working.
42:10And then up here, the spoil from that.
42:12You've got to be careful how you sculpt that into a landscape.
42:15In 10 years time, we look like just a natural valley.
42:19So, it just disappeared into the landscape.
42:21Exactly.
42:29My tunnel time is nearly up.
42:31I've seen the massive engineering it takes to cut through mountains and go where no one
42:38has ever been before.
42:40It's completely thrilling at an elemental, primal level.
42:44I've ridden my motorbike through Middle Earth.
42:48Oh, I'm loving this.
42:50I've met some truly heroic engineers.
42:53Once a tunneller, always a tunneller.
42:55And fulfilled a childhood dream.
42:57I told you about my mouth.
42:58Yeah, push.
43:02You are shaking, man.
43:03Yeah, no, absolutely.
43:04That is properly thrilling.
43:09This whole story starts and finishes with that, because it's that incredible landscape
43:14that's led to the creation of an entire underground world of vast excavated caverns,
43:19of tunnel boring machines, of specialist workers, excavating kilometer after kilometer after kilometer
43:26of underground tunnel.
43:27And all that work happening right now under my feet.
43:31Alright, let's see.
43:32Let's see.
43:33Let's see.
43:34Let's see.
43:37Then on Discovery Channel.