Original subtitles

[Narrator] These are the engineering wonders

of the United Kingdom,

their secrets revealed in a way never seen before.

Pioneers here help to forge the modern world,

inventing the railway and constructing vast bridges,

tunnels, and ships.

Today, UK engineers are building on this legacy,

creating cutting-edge structures

and machines on an extraordinary scale.

In this series, we reveal the secrets of the engineering

that built Europe's great nations,

the wonders that shape its cities,

landscapes, and history.

We reveal the astonishing innovations

and surprising connections

that help to forge this mighty continent.

♪ ♪

♪ ♪

The United Kingdom sits on the northwestern edge of Europe.

It's made up of England, Scotland,

Wales, and Northern Ireland,

and its wealth of natural resources and pioneering spirit

famously sparked the Industrial Revolution

in the 18th century.

Today, the United Kingdom is building

on its industrial legacy to meet the demands of the future

and continuing the visionary work

of its engineers and innovators,

who invented the steam train,

built revolutionary ships and seacraft,

and helped to connect the globe

with radio and the world wide web.

♪ ♪

Throughout the centuries, UK engineers have pioneered

some of the world’s most extraordinary machines.

♪ ♪

The Spitfire famously helped win the Battle of Britain

during World War II,

while British engineers developed the jump jet in 1967.

That spirit of innovation continues

to push the boundaries of aviation today.

In a remote airfield near Cirencester,

UK engineers are leading the race

for the future of flying machines.

♪ ♪

This is a pioneering electric battery-powered craft.

♪ ♪

Its propellers tilt to allow takeoff like a helicopter,

but it also has wings so it can soar like a plane.

Its designers hope these innovative aircraft

will fill the skies to revolutionize commuting,

carrying four passengers up to 160 kilometers per trip.

The market for electric craft like this

could be worth a trillion dollars.

The team have built two of these prototype craft to date.

The first person to fly them is Simon Davies.

[Simon Davies] When you look at this aircraft,

there’s a high degree of novelty.

There's battery electric power, electric motors,

miniaturized digital flight controls.

The level of complexity is more like a small fighter airplane

than a general aviation aircraft.

[Narrator] The eVTOL, as it's known, must undergo

rigorous testing before it can enter mass production.

Each step of certification tests its limits,

flying higher, further and faster.

A crucial milestone is to reach 20 knots,

a speed that creates lift,

making the craft fly more like a plane than a helicopter.

[Simon] That might not sound particularly fast,

but it's really important, because that's where we start

to get real benefit from forward speed.

[Narrator] It's a critical moment,

and the engineers are on high alert.

[Carmen Evans] We have a whole team in the control room.

We have specialists from all the different disciplines,

looking at the batteries, the engines,

the loads, flight controls.

[Simon] Okay, we’re cleared onto the runway.

[Carmen] I am ready.

[Narrator] Simon makes a final check of power levels

as he taxis into position.

[Simon] Have sufficient voltage.

[Controller] Confirm.

[Carmen] Confirm.

Control is go for flight.

Control is go for takeoff.

[Simon] All cams look good, and coming up to the hover.

♪ ♪

[Narrator] The eVTOL reaches the required height.

[Simon] Turning into winds.

[Narrator] And turns on the spot with eerie precision

to line up ready for the speed test.

All eyes are fixed on the data,

as Simon begins his forward run.

[Simon] TAC, accelerating.

[Narrator] As the plane approaches the target speed

of 20 knots, the air rushing over the wings

begins to lift the eVTOL for the first time.

Lift is vital, as it compensates for the weight

of the heavy batteries

and means the electric craft can travel further,

hitting their 160-kilometer target range

on a single charge.

[Carmen] Test at 20 knots, looks good.

[Narrator] The test is short but successful.

[Simon] It’s good, I’m decelerating now.

[Carmen] Terminate and land.

...on ground.

[powering down]

Alright, well done.

[Simon] Thanks. Test out. Good job, everyone. Thank you.

[Narrator] The dream of bringing this craft to market

is surprisingly close.

Final certification could be just three years away,

and full production could start shortly after that.

[Simon] I think we'll see the growth of heliports

in urban centers as people see that these aircraft

are actually practical, useful, and affordable,

a safe means of moving people around.

♪ ♪

[Narrator] UK engineers not only have a long tradition

of building pioneering machines for the air.

A strong naval heritage means they also excel

at constructing craft for the sea.

They invented the aircraft carrier in 1918

and the hovercraft by 1955.

On the Isle of Wight, engineers turn to electric energy

once again to power the next generation of aquatic machines.

♪ ♪

These remarkable hybrid electric ferries

have revolutionized green urban transport,

thanks to their groundbreaking use

of ultra-lightweight materials.

Now the team is going one step further.

They are nearing completion of their first

fully electric ferry, the Thames Orbit Clipper.

It's being fitted out to carry both pedestrians and cyclists

and will provide a fast, carbon-free route

across the Thames, seven days a week.

Tom Lilley has been involved with the project

for the last year.

[Tom Lilley] You can see we are in the very latter stages

of construction in here.

And here is our access for passengers,

and these two doors will allow the access for all the cyclists

coming on and off.

[Narrator] Traditional ferries are made of steel,

but steel is too heavy for a battery-powered seacraft.

So the team's groundbreaking solution

is to use an aluminium alloy that's uniquely formulated

to the shipyard's requirements.

[Tom] Our aluminium is brought on site,

cut and ready for construction,

and it essentially comes in with a number of codes on it,

and those codes relate to our designs that we have,

and it's essentially like constructing

a large Meccano set.

[Narrator] Although aluminium is light and strong,

it’s much harder to weld than steel.

The slightest moisture or even the grease from a fingerprint

is enough to compromise the strength of the joint.

This means that assembling these cutting-edge craft

is a skilled job, which must take place

in carefully controlled conditions.

[Tom] So here we are inside one of the hulls of the vessel.

And just past this bulkhead here,

we house all of our battery cells.

Along with that, all of the cooling system that's required

to keep those battery cells at the temperature

that’s safe and efficient.

[Narrator] Orbit's huge batteries give it

up to 17 hours operation on a single charge.

The ferry will also save energy by traveling in a straight line

back and forth across the river.

The craft's ingenious rotating thrusters

means it doesn’t waste energy turning around.

[Simon] These are one of our two 360-degree rotational thrusters.

We have one of these at each end of the vessel.

[Narrator] Instead of the whole boat turning,

the motors simply rotate to face the opposite direction.

And to operate the ship,

the crew simply spin their chairs around.

[Tom] The boat will go into this berth, lock in,

and then when we come back for the return journey,

the helmsman will spin 180 degrees

and be able to look out through this forward window here.

[Narrator] It’s taken engineers 18 months to build the Orbit.

And now the pioneering craft is almost complete.

[Narrator] Six weeks later, the Thames' first

fully electric passenger ferry is finally unveiled.

Once in service, it will transport 20,000 Londoners

every weekday, helping to make the capital's air cleaner

and marking the next chapter

in the UK’s proud maritime history.

♪ ♪

UK engineers have not only spearheaded

the invention of extraordinary machines,

they've also pioneered the construction

of epic infrastructure projects.

♪ ♪

The Industrial Revolution sparked a boom

in bridge building,

reshaping the landscape with iron and steel.

Iron Bridge in Shropshire,

the world’s first cast iron crossing.

And the Forth Bridges in Scotland,

each one a testament to three centuries

of engineering brilliance.

♪ ♪

In London, there's a bridge that best defines

Britain’s industrial legacy.

♪ ♪

This is Tower Bridge.

It’s one of the UK’s most beloved engineering wonders.

♪ ♪

It was built in the Victorian era

to connect the 39% of London's population

that lived to the east of its existing river crossings.

The bridge's road deck is designed to swing open

to allow tall ships to pass between its towers.

20,000 vehicles and 40,000 pedestrians

cross Tower Bridge every day.

Amazingly, river traffic has priority here.

By law, the bridge must open free of charge at any time

to allow ships over nine meters tall to pass through.

Operating the bridge is a heavy responsibility

for the workers on duty.

Jamie is about to carry out the first bridge lift of the night.

[Jamie] It's Friday night, it's just after rush hour,

but the traffic is still very busy.

So, the more bridge lifts we have,

the worse the traffic's going to get,

and some nights, the traffic will stay bad

till 11, 12 at night, depending on how many bridge lifts we do.

[Narrator] The first lift is due in half an hour

for the Dixie Queen, a replica Victorian paddle steamer

carrying party-goers.

Jamie goes to the engine room

to check that everything is ready.

On his way, he passes the bridge's

original steam-powered mechanism,

which sits alongside the modern electrical motors.

[Jamie] In the old days, there would be a lot of guys

struggling, filling the coal bunkers up

to charge up the accumulators.

Obviously, we don't use that these days

as we’re using electrical power.

[Narrator] The two decks of Tower Bridge

weigh 1,200 tons each.

Raising them is a challenge even for electrical power.

But Victorian engineers built in 400-ton counterweights

to balance the load.

So the bridge swings open almost effortlessly.

♪ ♪

As the Dixie Queen comes into sight,

Jamie stops the traffic and clears the bridge.

[Jamie] This is a public announcement,

bridge lift operations are about to commence.

Standby, bridge staff, start the motor.

[Narrator] While the bridge empties of traffic

and pedestrians, Jamie powers up the engines,

ready to pressurize the hydraulics.

[Jamie] Here we go. Now we have the bridge ready to move light.

[Narrator] Only when all these procedures are complete

can Jamie open the enormous bridge using a simple joystick.

[Jamie] I’m gonna have one final check for anyone on the bridge.

It’s all clear.

I’m gonna pull it back, and we’re gonna open the bridge.

[Narrator] Modern motors tilt

the Victorian era counterweights downwards.

And the two halves of the bridge begin to rise,

to the delight of the party-goers

on the paddle steamer.

[Jamie] For a vessel the size of this one,

we'll take the bridge up to about 30 degrees,

and that’s plenty of room for it to get through.

[horn blows]

[Narrator] To close the bridge,

Jamie runs through the sequence in reverse.

Ingenious engineering across a century

means this iconic structure can continue serving London

for years to come.

♪ ♪

In the Victorian era, visionary engineers transformed the UK

with bold infrastructure projects.

Isambard Kingdom Brunel built groundbreaking bridges

and railway lines.

And Sir Joseph Bazalgette revolutionized London

with a subterranean brick-lined sewer.

150 years later, it’s about to get an upgrade.

[Narrator] Deep beneath London, engineers are hard at work

constructing a brand new 4.5 billion-pound

underground megastructure.

The project is called Tideway,

but it’s better known as London’s Super Sewer.

Its scale is unprecedented, with a vast tunnel

stretching 25 kilometers along the route of the Thames.

Its engineers are working nearly 70 meters deep

to avoid burrowing into the city's

famous underground metro lines.

They use colossal digging machines

to excavate the sewer tunnel,

which is as wide as three London buses.

Yuriy Melnycho is a city engineer.

[Yuriy Melnycho] Knowing that you're working on a project

of this scale and this importance,

it’s challenging, but also rewarding.

[Narrator] London's Victorian sewage system is designed

to overflow into the Thames

when it’s overwhelmed with sewage and rainwater.

The Super Sewer will capture this overflow

and send it spiraling into the new sewer tunnel

deep beneath the river.

The tunnel stretches 25 kilometers across London,

taking the wastewater east

to a state-of-the-art water treatment plant.

♪ ♪

It's taken eight years of hard work to dig the sewer tunnel

and clad it with waterproof concrete blocks.

It’s an epic engineering wonder.

The team now have one final task to complete.

They need to fit the main tunnel

at Abbey Mills Pumping Station

with the UK’s largest ever manhole cover.

The tunnel's circular lid

weighs an astonishing 1,200 tons.

That’s around the weight of three jumbo jets.

[Yuriy] Everyone's put in countless hours

of planning and preparation.

And yeah, all falls down to, you know, today, and picking it up

and putting it down in the right place.

[Narrator] The gantry sits on a self-propelled

modular transporter, a heavy lifting machine

invented for moving enormous loads,

such as bridges or even spacecraft.

♪ ♪

♪ ♪

Once the lid is in position,

the team can begin to lower it down.

[Yuri] It’s going pretty good.

So hopefully by the end of the day, we’ll get there.

♪ ♪

[Narrator] The lid finally drops into place,

and the entire eight-year Super Sewer project

is complete.

Now London can look forward to a clean future,

no matter how big its population grows

in the decades to come.

♪ ♪

Railways are an essential part of the UK's infrastructure,

and the country has a proud history of rail innovation.

In the age of steam, British factories led the world.

Engineers here pioneered the first locomotive,

the first intercity services,

and the first subterranean railway,

the London Underground.

Now, a landmark project between the nation's largest cities

builds on this legacy, creating a record-breaking railway line

for the 21st century.

This is HS2, the UK’s biggest construction site.

Due to be completed within a decade,

this 57 billion-pound railway will form a high-speed link

connecting Birmingham in the Midlands

and London in the southeast.

With four vast new stations,

31,000 workers,

and over 300 kilometers of track,

it’s Europe’s largest infrastructure project.

Construction supervisor Ion Cocieri is working on

one of the project's most demanding sections,

where the line crosses the River Cole,

just outside Birmingham.

[Ion Cocieri] The metal segment is the biggest

from the River Cole viaducts.

Currently, we are working on the west part of the viaduct.

[Narrator] Engineers are laying HS2's twin high-speed tracks

side by side, on top of wide viaducts and through tunnels.

But here at the Cole River,

they need to do something different.

To preserve the natural shape of the river

and prevent flooding,

the line splits into two slim line viaducts.

One will carry trains south to London,

and the other will carry them west to Birmingham.

Landscaping around the viaduct

will create a sheltered, natural haven.

[Narrator] The HS2 viaducts over the Cole River must withstand

the force of trains traveling at 360 kilometers per hour.

So engineers use massive steel box sections like this one

to strengthen their cores.

The eastern viaduct is already in place.

Now it's time to lift its twin

onto its prefitted concrete pillars.

But its enormous weight and size makes moving it

a serious engineering challenge.

[Ion] The segment that you see around there have 273 tons,

is 73 meters length, and all the weight will be transported

by these self-propelled units

that you can see under the segment.

[Narrator] The team first transport the gargantuan girder

on two self-propelled modular vehicles

to the site’s heavy-lifting crane.

Each vehicle has 24 steerable wheels,

which turn in unison to give this behemoth

an extraordinary maneuverability.

The driver stands outside the vehicle

to get a much better view of tight spots.

It takes 30 minutes to transport the segment

the 400 meters to the site’s massive crane.

♪ ♪

Ion watches anxiously as the most delicate part

of the operation begins.

With just a few meters of clearance

from the eastern viaduct,

the team must maneuver the new massive girder

at a snail’s pace to avoid collision.

The Cole viaduct is part of the project's wider remit

to work with nature.

In order to preserve the landscape,

HS2 engineers have built many bridges, tunnels,

and cuttings along the line.

The enormous cost needed to achieve this

has caused controversy.

But for those behind the project,

it is a necessary investment

to minimize the track’s environmental impact.

At the site, the team successfully lowers

the massive steel unit into place.

♪ ♪

It's taken over 10 painstaking hours,

but the engineers can celebrate another milestone

in this remarkable project.

[Ion] It's just one more day that is making us closer

to have a fantastic new rail network.

♪ ♪

[Narrator] Scotland is modernizing its industrial past

with groundbreaking new infrastructure.

The Falkirk Wheel uses water-filled gondolas

to carry boats between two former industrial canals,

an upper and lower one.

And in Glasgow,

sci-fi structures from museums to arenas

line the nation’s famous heritage shipyards.

Now, the city is home to a river crossing

that builds on the legacy of that industrial might.

[horn blows]

This remarkable site is precisely half

of Scotland’s newest bridge.

Engineers are moving it from a workshop in the Netherlands

to its new home in Renfrew, Glasgow.

The team have already installed its matching half,

and once united, they'll form

the Clyde’s first-ever swing bridge.

♪ ♪

This stretch of the river is tidal,

so timing the arrival of the new bridge section is critical.

Site engineer Eilidh Love has been part of the project

from the beginning.

[Eilidh Love] We're working in a really tidal area here,

so we've had to look at the tide times to work out

when the best time for the barge to arrive was.

[Narrator] Finally, the barge sets off on its journey

up the Clyde.

Over 100 years ago, the Clyde was home to shipbuilding,

and the new bridge is part of a 1.3 billion-pound project

to regenerate the river’s former industrial areas.

♪ ♪

As night falls, two massive wheeled transporters

use hydraulic jacks to raise the 92-meter-long section.

They inch forward, crossing the 18-meter gap to shore

on precisely positioned platforms.

If the team's calculations are correct,

the bridge will glide perfectly onto its rotating base.

[Eilidh] There's 108 bolts, which are part of the bearing,

and the bridge has 108 holes which have to line up perfectly

for the bridge and the bearing that we've built here in Renfrew

to fit together.

[Narrator] Once the bridge is lined up in position,

the team gradually lowers it onto its bearing.

All 108 bolts fit snugly into place.

[Narrator] As day breaks over Glasgow,

the first swing bridge on the Clyde

is finally ready for testing.

[Jim Armour] Nice still day for moving the bridge.

It’s good conditions.

[Narrator] The two sections must not only swing to and fro,

but also lock securely in the middle.

[Jim] The bridge will swing, slows up, meets in the middle,

then the expansion joint closes up.

[Narrator] The bridge will expand or contract,

depending on the air temperature.

So a special joint deploys between the two halves

to make up any gap.

The big question, will it work?

♪ ♪

♪ ♪

The two halves line up perfectly,

and the expansion joint closes up the gap.

Two years of meticulous construction and planning

have paid off.

♪ ♪

♪ ♪

UK engineers have not only blazed a trail

for cutting-edge infrastructure projects,

they are also pioneers

of spectacular architectural wonders.

♪ ♪

The United Kingdom's legacy of innovation

goes beyond industry.

They invented many sports, too, including football,

establishing its official rules in 1863.

The UK is home to some of the oldest clubs in the world,

which play in state-of-the-art stadiums,

where history meets modern engineering.

In Liverpool, there's a new stadium that showcases

the city’s proud legacy in both football and shipping.

♪ ♪

Here, British engineers are racing to complete construction

of a spectacular new home for Everton Football Club

in the city’s historic docklands.

This next-generation 500 million-pound stadium

will seat over 52,000 fans.

♪ ♪

What's extraordinary about this stadium

is how it's being built,

without damaging the protected dockland it sits on.

Project Director Gareth Jacques has been supervising the build

for the last four years.

[Gareth Jacques] Another busy day today

down at Everton Stadium.

We've got just short of 800 people working on site

at the moment, and we’re doing our final testing, inspections.

[Narrator] Work began on this build in 2021.

The first task was to create a solid base for the stadium

in the existing Victorian dock, filled with water.

The remarkable solution was to pump in

nearly half a billion cubic meters of sand,

scooped from the Irish Sea.

To speed up the process, engineers mixed the dry sand

with water, forming a slurry that flowed easily into place.

Once drained and compacted, the sand created a level surface

for the stadium to sit on

while leaving the dock below untouched.

[Alix Waldron] The construction methods that we've used

was all around protecting the dock itself.

So if somebody at some point in the future wants to come

and reverse engineer it back into a dock,

it is possible to do so.

[Narrator] The team then erected the stadium from giant modules,

fabricated off-site,

slotting them together like flat-pack furniture.

This minimized the need for construction machines

which could damage the historic dock with their weight.

Everton’s old home is Goodison Park.

When it was first built in 1892,

it became England’s first purpose-built football stadium.

And over the years,

it has been expanded and modernized many times,

and once boasted England’s biggest stand.

But the club has now outgrown Goodison Park,

and with no room for expansion, they had to find a new home.

[Alix] There's so much about Goodison

that we absolutely love and adore,

and it’s going to be really sad when we have to leave.

But we sell out week to week now,

and we've got a growing waiting list of fans

who want to be able to purchase a season ticket with us,

so we’ve had to look elsewhere.

[Narrator] The most striking part of the new stadium

is its wraparound aluminium roof.

Each panel is perforated to buffer the wind

and to divert rainwater into underground tanks

to water the pitch.

The stadium's facade of red brick is designed to blend

with the dock’s famous hydraulic tower.

It once housed a steam engine that opened the lock gates.

Gareth's team is on track

and nearly ready for the new season to begin.

[Gareth] I sincerely hope that the fans love the stadium,

and it becomes their home for years and years to come.

And if they love it, and the atmosphere is brilliant

and it helps Everton win, then we’ve done our job.

♪ ♪

♪ ♪

[Narrator] The UK has a long history

of groundbreaking high-rise architecture.

Liverpool's Royal Liver Building was one of Europe's

first skyscrapers in 1911.

While the 310-meter-tall Shard

became the nation’s tallest building in 2012.

♪ ♪

In Bedford, one UK company builds on this legacy

with a remarkable new way to reach the sky.

♪ ♪

This bustling site is a remarkable assembly line

for skyscrapers.

Here, workers build high-rise homes, room by room,

on a factory floor.

Each apartment is built from a series of fully fitted modules,

complete with windows, insulation, wiring,

and even bathrooms.

Workers transport the modules to site,

where cranes stack them together like building blocks.

♪ ♪

This method brings indoor factory efficiency

to large scale outdoor construction,

whilst avoiding weather delays,

which can wreak havoc with builds outdoors.

The factory-built skyscraper is the brainchild of John Fleming.

[John Fleming] When designing a building,

we allow the architects a total flexibility,

and we manufacture units as per their design.

[Narrator] John and his team have been building

these high-rise towers in the UK for over 10 years.

And in South London, they are undertaking

their biggest challenge to date,

constructing the tallest modular tower cluster

in the world.

It takes the team a little over a year

to erect two tall concrete cores.

The cores enclose the stairs and elevators

and act as a spine for the modules to stack around.

But the higher they build, the tougher the job becomes.

[Narrator] London's record-breaking

modular skyscrapers are taking shape,

but the construction must be geometrically perfect

so that the towers don’t tilt as they grow taller.

[John] The most critical part of the erection process

is erecting the modules accurately,

not even out a millimeter,

to make sure everything will follow correctly above it.

[Narrator] The tallest tower will be 50 stories high,

reaching up a dizzying 163 meters.

Its 546 apartments are constructed

from over 1,500 separate modules,

which must sit perfectly square to each other.

The precision of the assembly on site

begins the moment the crane connects to the module.

[John O'Dwyer] The more level it is, the easier it is

for the install crew on top of the 43rd floor

to put it in place.

[Narrator] The team carefully stack the modules,

floor by floor, lining them up as they go.

They must position each module with an accuracy

of 0.7 of a millimeter,

the thickness of two business cards.

They use up to six structural connections

to secure each module to its neighbors.

Using traditional methods, a project this ambitious

could take up to half a decade to build.

But as the team unloads and clamps the last few modules

into place, they complete these record-breaking towers

in just 26 months.

It's a proud moment for the whole team,

as these pioneering new skyscrapers

join the UK skyline.

♪ ♪

Engineers in the UK have a long history

of building extraordinary architectural wonders

designed to nurture exotic plants.

In the 18th and 19th centuries, mega-scale greenhouses,

like Kibble Palace in Glasgow,

wowed visitors with their scale and unique specimens.

♪ ♪

Now, engineers in Cornwall have taken this horticultural legacy

to a whole new level.

♪ ♪

This extraordinary construction is known as the Eden Project,

a pioneering glass house without glass

that warms and protects the world's

biggest indoor rain forest.

Its design is inspired by soap bubbles,

and the biggest dome soars 50 meters tall,

high enough for the Tower of London to squeeze inside.

A steel skeleton supports over 800 inflated pillows,

made from a plastic

just 1% of the weight of traditional glass.

♪ ♪

Engineering manager Kevin Bate is in charge of maintaining

these remarkable lightweight domes.

[Kevin Bate] I think we like to say

we’ve got cling film with attitude.

If the biomes were ever made of glass,

the weight would be incredible,

and quite dangerous, to be honest.

So that's why this material was chosen;

minimum material for the greater strength.

[Narrator] These groundbreaking plastic pillows

are now 25 years old.

So Kevin is leading a project to replace them.

[Kevin] After some extensive surveys, it was determined

that some of the pillows are starting to turn opaque

due to natural aging.

If they turn opaque, they don't allow quite so much sunlight

to penetrate through them to be able to heat the biomes up.

[Narrator] The new panels are made up of three sheets

of plastic sealed at the edges.

The team need to inflate them like a balloon.

First task, they must remove the old pillows

without letting out the vital heat

that helps to nurture the tropical plants.

[Worker 1] We’re gone for valve placement first, so.

[Worker 2] This is where the valve is, good.

[Worker 1] Yeah.

[Narrator] Once it's aligned, the new panel acts

like a blanket to prevent the hot air from leaking out,

as they cut away the old pillow underneath, section by section.

They slide metal beads around the edges of each pillow

and hammer them into slots that sit between the metal tubes.

[Worker 1] Here it goes!

♪ ♪

[Narrator] Finally, the weather-damaged sheets

drop down inside.

Once the panels are airtight,

it's time for one of the team's daring specialists

to climb 35 meters to the top of the dome,

to connect the new pillow to the clever inflation system.

♪ ♪

Once inflated, each pillow is strong enough

to support the weight of a car.

But on a hot day, pressure inside them

can rise beyond breaking point.

So there are sensor pillows dotted over each dome,

which detect changes in pressure and trigger pumps

to keep all the pillows in perfect shape.

♪ ♪

As the team finish up for the day,

they know that the fragile ecosystem that grows below

this extraordinary wonder is safe for another 25 years.

♪ ♪

♪ ♪

The UK is a nation of innovators

who transformed the world with their daring ideas.

Today, its engineers continue this legacy

and push innovation to the limit,

to create a brighter future for this great European nation.