This is one of the world’s biggest construction
projects. A $7.5BN feat of engineering that’s gonna
transform travel across an entire continent. And it’s happening here. On the quiet German island of Fehmarn. Let me explain. This is the Scan-Med corridor. It’s the northern axis of the trans European
transport network, and it spans nearly 5,000-kilometres from Malta in the mediterranean to Finland's
icy tundra. Along the way it drills through Alpine mountains
and crosses the sea. But follow the route north and something strange
happens. Instead of being able to go straight on towards
Sweden, you have to take this 500-kilometre detour through Denmark. And it’s all because of this, a stretch
of water between Germany and Denmark called the Fehmarn Belt. So, let’s just get this straight. There’s currently a 55-kilometre tunnel
being dug through a mountain in Austria, there’s an epic bridge between Denmark and Sweden,
there’s another massive bridge linking two Danish islands – but we can't get over this? It might not look like much but this unassuming
stretch of water has thwarted the plans of the world’s best engineers for decades. Until now. This is one of Europe’s largest construction
sites. It will be the longest immersed tunnel in
the world. There’s no instruction manual for building
anything like this. The fastest route between Scandinavia and
central Europe. I mean, the risk is people never stop, maybe they
just pass through. What are your concerns with this scheme? They’re destroying our nature. We’re building the Fehmarn Belt tunnel between
Denmark and Germany. You might not have heard of Fehmarn, or its
tunnel, but this is one of the most technologically advanced mega projects on the planet… Absolutely enormous, it’s like an aircraft
hangar in here. … and it kind of epitomises the power of
construction and its ability to change our world Oh wow, this is absolutely incredible. You get those moments in infrastructure when
they nail both the engineering and the architecture and they come together. I saw it on the Elizabeth Line, did it really
well, London’s new railway. Getting the same feeling here. I am currently driving over the Øresund bridge,
one of the world’s most incredible feats of engineering, probably one of its best infrastructure
projects. It’s this structure that links two countries,
it links Denmark and Sweden… This is where the whole story starts. It was when this was being planned that Sweden
had a big idea. So, right now to get from Sweden down into
Central Europe, you have to catch a train here at Malmö. That takes you over the Øresund crossing
to Copenhagen where you change onto another train that eventually takes you into Hamburg
and down into Germany. Even on a high speed train that takes you
five and a half hours, and for a freight train it’s even slower. Germany is Sweden’s second biggest export
market, so that’s a huge deal. The Swedish government saw a shortcut here
at the Fehmarn Belt so they said to Denmark “we’ll help you
build the Øresund bridge if you look into the possibility of a new fixed link in the
water behind me”. Fortunately that request wasn’t as outrageous
as you might think. So here’s Denmark and this is the German
island of Fehmarn, which gives the Fehmarn Belt its name. Now there’s been talk of creating a railway
between Hamburg and Copenhagen since the 19th century, but nothing really happened until
the 60s when a bridge was built here. That route was then extended to a new ferry
port at Puttgarden bringing trains right up to the water's edge. Amazingly the trains were then loaded onto
ferries and carried over the Fehmarn Belt and onto to Denmark. The whole thing was pretty slow. Diesel trains weren’t as fast as the ones
we have today, and the ferry itself took about 45 minutes. For years people talked about the idea of
a fixed link between these two countries, a bridge or a tunnel, but it wasn’t until
Sweden threw down the gauntlet that things got really serious. It was way back in 2008 that the Danish and
Governments first signed a treaty to start work on The Fehmarn Belt Fixed Link. There was a lot at stake. The idea was to replace the ferry with a new
permanent crossing. It would have a four lane motorway and two
rail lines serving both freight and high speed passenger trains – and the whole thing would
be funded by Denmark who would also collect the toll fares and run the onshore businesses. Separately, Germany would upgrade the route
from Puttgarden to Lübeck to allow for the new trains and traffic to pass through. That would also involve building another,
much shorter tunnel to the German mainland here at Fehmarn Sound. It would be a once in a generation upgrade
of the transport network. The Hamburg to Copenhagen corridor would be
transformed into a high speed rail and road route, the Swedes would get their shortcut
to the continent, a massive detour would be wiped off the scan-med corridor and that,
in turn, would transform the wider Trans-European Transport Network. The only thing that stood in the way was the
water. The most obvious solution was a bridge. This is what they came up with: a 3-kilometre
long, cable-stayed bridge sitting about 65-metres above the water so that ships could still
pass underneath. It probably reminds you of the Ørseund bridge
and it would have been similar but nearly three times as long – and that’s where
the problems began. You see, the Fehmarn Belt is pretty awkward. From there to there is just under 20 kilometres
and that’s further than the Øresund bridge had to cross. Also the depth of the water out there in the
Baltic Sea is 40 metres and the soil conditions aren’t great for building on. That all meant that the bridge would have
needed spans of over 700-metres. Nothing like that has ever been built for
a combined road and rail bridge before. The plan was for three huge pylons each just
under 300-metres tall. The foundations of those would have to be
built at sea in depths of up to 25-metres. Throw in poor soil conditions and a busy shipping
lane and you have an engineer’s idea of hell. Then – as you’ll have gathered from my
trip on the ferry – there’s the wind. Now, some of the world’s biggest bridges
– the Øresund bridge, the Çanakkale bridge in Turkey or the epic Hong Kong Macau crossing
– all share a common trait. They all, more or less, run horizontally from
east to west. A bridge crossing the Fehmarn belt would have
had to go from north to south, meaning every train, truck, car and YouTuber trying to make
a video, would get battered by the prevailing winds blowing from west to east. So after careful consideration of the risk
of cost overruns and the technical complexity of construction, the bridge was firmly ruled
out. If you can’t go over, you’ve gotta go
under. But it’s OK because the Fehmarn belt is
the ideal place for a bored tunnel. Now there’s a few reasons why bored tunnels
are great. First off they don’t disturb anything above
ground. That’s why they’re usually used for underground
railways in cities but that’s also great for a place like Fehmarn which has a delicate
ecosystem that could take years to recover from all the disruption caused by building
a bridge. They’re expensive but they tend to be more
economical the further you go. So the team looked into the possibility of
a bored tunnel under the Fehmarn Belt. But that too hit a snag. Bored tunnels are dug by a tunnel boring machine
– or TBM. The width depends on the TBM but something
like London’s new Elizabeth line used machines around seven metres wide. They’re good for something like an underground
railway because you have one track per tunnel. But Fehmarn needs a railway, motorway and
an access tunnel. That could mean boring 5 tunnels at five times
the cost. And that’s not all. Very little of a train’s surface area actually
sits on the track and because the wheel’s are made of steel, or at least they are in
real life, there’s very little traction. On flat tracks that’s great, it’s one
of the reasons trains are so fast and efficient. But going uphill becomes a bit more challenging. The average mainline train can drive upwards
by 2.5 percent or 1 in 40. Meaning that for every forty metres of track,
the train can move upwards by one metre. The Fehmarn belt tunnel sits 40 metres deep. Any bored tunnel would have to tunnel at least
10 metres below that and incredibly long in order for a train to travel into it, pass
under the ocean and pass successfully again up the other side. A shorter tunnel would create a train track
that’s incredibly steep and any train probably wouldn’t make it. So a bridge is too difficult, a bored tunnel
is too expensive. It’s not looking good. Thankfully there was one last option on the
table: The Immersed Tube Tunnel Now, I know what you’re thinking, finally
another shot of Fred Mills on a beach. A freezing cold beach in the Baltic. The way this tunnel is built is actually pretty
straight forward. First of all you create your tunnel segments
in a nice, dry factory on the land. Then instead of digging a deep tunnel underneath
the seabed, you just dig a trench in the bottom of the seabed. Then you take your tunnel elements and lay
them in one by one, and seal them together as you go. Then you cover the whole thing over… …and hey presto you’ve got a tunnel. It’s a great solution for a place like Fehmarn. You don’t have to build a bridge where you’re
going to be subject to the wild weather and the ocean, you don’t have to dig a deep
tunnel, which wouldn't really work for a train and shipping lanes above stay open. Keep driving over the Øresund bridge and
you hit a man made island and suddenly drop down under the ocean, I’m driving under
the water right now, this is very, very cool. This is the Drogden tunnel, which is itself
an IMT, it’s a preview of what’s going to be built down at Fehmarn. Now, some people have asked, why did you go
through the hassle of building a tunnel and then a man made island and then a bridge up
here at the Øresund crossing And it basically exists because of Copenhagen
airport – there were restrictions to do with height around that. IMT’s are usually used for fairly short
stretches like rivers and harbours. This is one of the longest IMTs in the world
and it’s only 4-kilometres. The Fehmarn tunnel will be five times longer
– making it an immense feat of engineering. So how the heck do you build something that
big? Well, it all starts here I’m currently standing in Rødbyhavn on
the Danish side of the Fehmarn Belt and at one of the biggest construction sites in Europe. It’s all run by the Danish state owned company
Femern A/S. And this place is so big, it’s taken them
two years to build just the work area. The place is a hive of activity, there’s
a village for 1,300 workers, a specially built harbour for material deliveries, and the northern
portal, where the tunnel will come up to the surface. But the star of the show is easily the massive
building behind me, this is the factory where the tunnel segments are going to be made. It’s one of the biggest factories ever built
in Denmark, all together covering half a million square metres, that’s around 200 football
pitches. These buildings are vast because they need
to be. The 89 enormous concrete tunnel elements that’ll
be constructed here will each be 220-metres long and 40-metres wide – that’s so that
they can fit two railway tunnels, two motorway tunnels and a service route all side-by-side. Building an IMT tunnel under the ocean works
like this. Initially the team constructed a new work
harbour on the coast so that materials could be brought to the site by sea. That’s enabling them to build these enormous
tunnel factory buildings that’ll contain six production halls in total. Once fully up and running these factories
will be on 24 hours a day, seven days a week – for three and a half years. Aggregates and materials will be delivered
to the work harbour and then taken by conveyor belt to the factories. In here each of the 89 tunnel elements will
be cast – but they’re so big they’re actually formed of 9 segments. Actually, it takes 36 hours to cast one segment. It has a very, very detailed plan, like if
you are baking an enormous, advanced cake. It has to be the right temperature before
you go to the next layer, next layer. Not too... Not too cold, not too hot, not too wet, not
to dry. And then in 36 hours, they have made one segment
and we have to make sure that the concrete are running for all 36 hours. Once a complete tunnel element is constructed
it’ll be rolled out of the factory and taken here to the upper basin, where huge doors
will close behind it. Rather like a lock, the basin will then be
flooded, ballast tanks will enable the element to float and tug-boats will move each section
down to the lower basin, and then out to sea. They are then taken here, where the trench
they will sit in is currently being dug. Now, that’s the first challenge this project
throws up. IMTs normally sit 20 metres deep. This is 40 metres. Once the trench is ready, the next step of
getting a 73,000 tonne concrete tunnel segment to the bottom of the ocean isn’t too difficult
– its ballast tanks are simply flooded and gravity does the rest. But getting each segment into the right place
is much harder. Along the entire 18-kilometre route, they
have to land within 15mm of their targets. To make the whole thing watertight the tunnel
segments are fitted with something called a gina gasket at one end. Once laid in the trench next to another segment,
the water is pumped out of the space between the two bulkheads creating a partial vacuum. This pulls the two concrete segments together
and the gina gasket gets squashed in between them, creating a seal. Once all the elements are in place, the trench
is back-filled and the tunnel is covered in gravel to protect it. At this point, nature takes over and eventually
covers the gravel bed with sand. Then there’s just the small matter of fitting
the whole thing out with lighting, ventilation, a motorway and a railway before the whole
thing opens in 2029. That’s basically it. Easy right? Wow, it’s absolutely epic, the size of this. It’s huge. On paper the process seems logical and practical. But seeing it up close, you can’t help but
feel dwarfed by the immense scale of both its engineering and ambition. Well, this is production hall B, which is
one of three production halls where we will be casting the tunnel elements for the Fehmarn
Belt tunnel. This one is the furthest ahead of the three. It's 98% completed. And right now as we're entering they're just
busy setting up the internal cranes, the formwork and all the equipment we need for casting
elements. Absolutely enormous, like an aircraft hangar
in here. It is. You could easily park a 747 or two in here. Wow! This has actually been pretty fast. We've been working on the factory's site here,
what we call the PFA, the production facility area for about a year. So everything you see here is basically shot
up out of nowhere over the last 12 months. What keeps these engineers awake at night
is not whether their foundations and calculations are correct, it’s the sheer logistics of
getting all these tunnel segments built and out to sea in an orchestrated way. There isn’t anywhere big enough to store
them so as soon as they’re made, they’ve got to be taken straight out to sea. To make sure nothing stops the production
schedule once its started, engineers have been practising and honing nearly every step
of the process. I’ve now got a chance to get up close to
a test segment which has been constructed. This, behind me is just one of the rail tunnels
from just one end of a tunnel segment and you can see, from me standing in front of
it, the immense scale of this project. This is our testbed, where we are testing
our production method, our forms, um, our crews, and, of course, the concrete that we
are going to use to cast the tunnel elements. What we're actually building is not not even
two rail tunnels, one and a half rail tunnels here. The actual standard elements will be 42 metres
wide. But it's big enough for us to experience the
scaling issues that are involved in building something like this. There's no instruction manual for building
anything like this. You know, we are learning as we go and we've
learnt a lot about the importance of communication between our crews and the way our concrete
behaves over the casting period. And we're going to take all that know how
and make a few more minor scale tests before the real deal starts up at the end of the
year. What’s being built here is proof of how
construction is constantly learning and evolving. Thirty years ago when the Øresund bridge
was being planned a tunnel like this wouldn’t have been deemed feasible. The principles of this tunnel are the same
as any other tunnel from Sweden to Hong Kong, but our knowledge and skills have now advanced
to a level where we can go deeper and further than ever before. When this tunnel completes in 2029, thousands
of cars and hundreds of trains are going to pass through it every day and that’s going
to be a game changer not just for Denmark and Germany but for the wider continent. But it all costs a lot of money, $7.5BN. Now, half a billion dollars of that is coming
from EU subsidies, and the rest is coming from a loan by the Danish state. Crucially, Danish taxpayers won’t have to
spend a single penny. Now, the cost of the tunnel is going to be
repaid over time by the revenue that comes from tolls from cars. It’s likely that cars are going to be charged
about the same as the ferry, about €100 to use the tunnel. Now, it’s projected that Denmark could receive
around $4BN in profit during the first 50 years of the tunnels life. So, improving infrastructure, creating green
travel corridors, and billions of dollars in profit. What could possibly be the problem? Ah… It’s not just the Fehmarn Belt’s geography
that this construction team has had to battle. Campaigners on the German side of the sea
have fought tooth and nail for the last decade to prevent the construction of a permanent
crossing. I've been coming here as a child It's the most sunniest spot in Germany. Even if it's a little a little colder than
in the south, it's one of the most sunniest spot in Germany. And up to now, it's very silently. Yeah. You've got you've got a landscape. You've got the free ocean. You can go swimming, you can do water, sports. This is the downside of massive construction
projects. Any new mega scheme has to be built somewhere,
whether that’s in a virgin forest, in the middle of a city, or on a quiet German holiday
island. Whether you like it or not it’s going to
have a massive impact. They're destroying our nature. They're destroying the foundation for our
economics and they're destroying the foundation for ecologics we have here. Some people worry about the impact this construction
project will have on the unique ecosystem of the Fehmarn Belt. The marine life in this area of the Baltic
sea thrives on clear water conditions and the concern is that digging the trench for
the tunnel is going to disturb that. The ecology of the Fehmarn Belt is very diverse,
the clouding in the Fehmarn Belt will reduce the growth of macrophytes of plankton and
will of course have repercussions on all living fauna and marine flora. Femern A/S say sedimentation is one of the
most closely monitored environmental impacts on this project. They say they use special dredging machines
to minimise the spill and have patrol boats and monitoring stations around the dredging
site to collect data on water clouding. This and other environmental data is published
in real time on the Femern A/S website in an effort to improve transparency around the
construction. But it’s not just the marine environment
Hendrik and Isabel’s organisation is concerned about. A big feature that is being touted about this
new tunnel is that it’ll kind of provide a new green link to the continent. Femern A/S say that because the distance between
Hamburg and Copenhagen is being shortened thousands of vehicles will have to drive 150km
less. The new rail service will take cargo out of
lorries and place them on to freight trains. And the new rail link will make taking the
train a more attractive option. As well as wanting to improve freight connections,
the Swedes are also very keen to avoid something called flygskam is that alright? Flygskam, flygskam and pretty much want to make taking the train
easier than flying as much as possible. That idea is gaining traction. In April 2022 France banned all internal flights
under two hours and other countries are considering doing the same. If that’s going to catch on, then good high
speed rail links like this are essential. But – and this is a big but – constructing
something as ambitious as the Fehmarn Tunnel comes with a huge carbon footprint, mostly
from the vast amounts of concrete being produced. Only the prefabrication of these concrete
tunnels will produce 2 million tonnes of carbon dioxide. FemernA/S say the Fehmarnbelt tunnel is a
generational investment in a greener and climate friendly transport corridor in Europe. Once completed, the tunnel will deliver a
significant contribution to a green transeuropean traffic corridor by creating a 160 km shortcut,
creating a viable alternative to air traffic and shifting goods from trucks to electrified
freight trains. They added that they are making a concerted
effort to reduce the CO2 footprint of construction, but it’s not possible to build at this scale
without causing some emissions. Just one of the initiatives is our commitment
to use 100 percent renewable energy sources for construction and operations of the tunnel. Fehmarn is beautiful and you should keep it
like that, not changing it into a transport spot. Inevitably infrastructure comes into contact
with the natural world. How couldn't it?. That doesn’t mean concerns should be brushed
aside, it also doesn’t mean we should never build infrastructure ever again. What Isabel expresses are legitimate anxieties
from people living on the doorstep of one of Europe’s biggest construction projects. When there is a good case for a new megaproject,
it’s important that project teams listen to concerns and work to reduce the impact
of their work on people's lives and the environment as far as possible. That’s something this project has set out
to do from the start. Most of the construction activity is being
done on the less-populated Danish side of the water and new habitats are being built
to compensate for land now occupied by the factory. Critics of the fixed link say that the whole
project is speculative and that there’s no way definitely confirming whether or not
it was worth the money. That’s true – and its the case with almost
every other infrastructure megaproject out there. The same was said about the Øresund bridge
and its now a revered structure that millions of people rely on. Tourism is a big part of this island’s economy
and it could take a hit during construction, but in the long run it could benefit from
the improved connectivity. Over the next decade a new route will be tattooed
onto this part of the map – and for the people who use it, its convenience will erase
any memory of the enormous effort that it took to make it happen. The bridge behind me is 60 years old and links
the other side of Fehmarn with the German mainland. It was vehemently opposed when it was first
constructed but now with the construction of another new tunnel under this stretch of
water, people are concerned for its future, they’re worried it might fall into disuse
or even disrepair. That for me is the story of modern infrastructure,
yes these projects are difficult and controversial to realise when they’re first constructed. But they go on to have a defining impact on
all of our lives. The new tunnel under the Fehmarn belt will
impact millions of people across this continent over the decades to come. Any of the controversies around its construction
will likely be forgotten and the extraordinary engineering that went in will be taken for
granted. That’s all from me on the sunny island of
Fehmarn, as always guys if you enjoyed this video and you want to get more from the definitive
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