Original subtitles

[dramatic music]

- [Narrator] They are much more than just huge bridges.

They are technological benchmarks, manifestos of their time,

the most spectacular bridges on earth

allowing travel on four wheels.

Hundreds of thousands of cars,

huge rumbling trucks weighing tons roll over them

on a daily basis.

The constant traffic makes the maintenance monsters.

- Even though it's very big,

it has a lot of intricate details

that have to be maintained.

- [Narrator] These bridges have to endure jolts daily.

They stand in extreme locations,

and have to be serviced under the toughest circumstances.

- [Translator] You have to hold on tight.

The wind blows up to 60 kilometers an hour.

- [Narrator] The huge challenge begins with the construction.

- [Translator] They're crazy, they'll collapse.

- [Narrator] A multimillion dollar gang

that often drives the construction workers

and engineers to the verge of bankruptcies and madness.

- Everybody was pessimistic.

- [Narrator] The gigantic structures break boundaries,

but at a price, human lives.

- [Radio] Skyway Bridge is down.

It's mayday, emergency situation.

Stop the traffic on that Skyway Bridge.

- [Narrator] But when it's completed

and the first cars drive across the bridge,

suddenly it's only magic and pride.

- To me, it will be the most beautiful bridge in the world.

- [Narrator] Huge constructions, roads sweeping across them,

the secrets behind the gigantic architectural wonders

and their daily maintenance challenge.

Gigantic constructions,

the most spectacular bridges in the world.

[upbeat music]

Majestic, gigantic, iconic.

No matter the superlative, it is justified,

but without a few key milestones

in the history of bridge building,

these constructions would be completely unthinkable.

The first wave of innovation takes place in the 1930s.

For the first time,

people need bridges for heavy automobiles.

In the 60s and 70s,

the bridge builders ignite the next stages of development.

No wonder, as car travel goes through the roof worldwide

with more new cars on the road than ever before.

Further, huge waves of innovation

and bridge building construction

make it possible to build ever higher, sturdier, and larger.

[dramatic music]

Our first milestone on the road to gigantic monster bridges,

the Europa Bridge in the Austrian Alps.

At its completion,

the Europa Bridge is the highest on the continent,

boasting the tallest pillars in the world.

[tense music]

The Europa Bridge is located north of Innsbruck in Austria.

13 million vehicles cross the highway bridge every year,

2 million of which are heavy trucks.

Weighing up to 38 tons,

they cause continuous stress for the bridge.

The Europa Bridge is the heart of the Brenner Highway,

the main north-south transit route in Europe via the Alps.

190 meters above the Vip Valley,

the bridge has spanned the valley for over 50 years now.

Prior to construction,

the only way to reach the Brenner Pass was a small road,

one lane each way, one winding road after another.

Today, the journey takes you over

five gigantic reinforced concrete pillars.

The bridge core is a steel box girder.

It supports the roadway and is regularly checked for damage.

With spans of up to 200 meters,

the slightest material fatigue can lead to disaster.

The bridge must undergo regular maintenance.

Because of high traffic, the strain is enormous.

Another problem is that the bridge is located

in a strong windstream.

The fall wind comes from the mountains and can reach speeds

of up to 150 kilometers per hour, hurricane strength.

[wind howling]

It is windy today,

and important maintenance has to be scheduled.

Bridge Inspector Peter [indistinct] and his colleague

Dominic Lightner want to venture out

over the parapet using this machine.

Due to the strong winds,

it is questionable if a check will be possible.

- [Translator] Because we are located in a Chinook wind,

it often happens that we have to postpone maintenance works

or sometimes even have to cancel them.

If the wind is too strong,

the risk of an accident is too high.

The bridge inspection device is still in the slipstream

at the head of the bridge, but to carry out inspections,

the device has to move much further out over the gorge.

Peter and Dominic get a better picture

of the current conditions at the first concrete pillar.

- [Translator] No wind here right now.

It's misleading though because you can hear it

but not feel it.

Out there, it's a different story.

- [Narrator] Since the last inspection,

the weather conditions have taken its toll on the concrete.

Dominic Lightner and Peter [indistinct] want to know

the condition of the steel box girder.

Provided the wind plays ball.

The two inspectors take a chance and walk

to the middle of the bridge.

The wind is a lot stronger here.

Typical of the treacherous alpine region.

- [Translator] You have to hold on as wind gusts

up to 60 kilometers an hour out here.

- [Translator] Device wise, it's tricky.

Some functions don't work at all at high wind speeds.

We're restricted or we have to abort.

- [Narrator] Not a chance.

The winds are too strong.

No inspection possible today,

but due to the constant strain,

regular inspections to the underside

of the roadways are imperative.

Strong gusty winds, extreme traffic, and heavy vehicles.

The bridge is more than 50 years old.

Martin Kirchmeyer,

the current Europa Bridge Chief Inspector,

sees the bridge as a small wonder of the world.

- [Translator] We have here in Wipptal southerly wind gusts

of up to 150 kilometers per hour,

causing strong vibrations on the entire construction,

making it all the more fascinating for us to think

how our piers from decades ago

managed to deal with such complex construction,

but with much more modest technical capabilities.

- [Narrator] The almost 150 meter high concrete pillers

are hollow inside, like the hollow steel box girder.

Everything is extremely streamlined.

The bridge is one of the first structures where tests

were carried out in a wind tunnel

in order to avoid excessive vibrations and overloads,

allowing the Europa Bridge to withstand at least 10 times

more traffic than back when it was completed.

- [Translator] We got lucky because in the 1960s,

the calculation methods were not as precise as they are now,

so the engineers had to add some reserve here and there.

That has really helped us today.

[tense music]

- [Narrator] When construction began in 1959,

concrete pillars of that height

had never been erected before.

And of all places, in an alpine region,

definitely a monumental task.

Working conditions, strong winds, intense cold,

all at extreme heights.

Danger is omnipresent.

22 people die before a single car rolls over the motorway.

Two weeks after the failed mission, today,

the men want to go at it again.

Give it another try, assuming the weather is favorable.

Like every inspection here, the bridge remains open.

Traffic flows.

Closing the bridge for any amount of time, unthinkable.

For the inspection, only the right lane is closed.

The men maneuver the bridge inspection device into position.

Whether the inspectors can check the road base today

will only become clear once they have positioned

the device in the middle of the bridge.

It had to be postponed several times over the past few days

due to high winds.

Dominic and Peter are optimistic for today.

- [Translator] 10 kilometers an hour.

- [Translator] We measure 10 kilometers an hour.

In our business, that's practically windstill.

Today we can use our device.

- [Narrator] Finally ready to go,

190 meters above the valley floor.

- [Translator] Hi there.

It's looking pretty good with the wind today.

It's not that bad. You get used to the height.

- [Narrator] Peter and Dominic descend

to one of the most spectacular work environments

in all of Europe.

Fear of heights is not recommended.

The inspector's task,

to document damage and schedule repairs.

- [Translator] Martin, can you back up a bit?

- [Narrator] The box girder was widened 30 years ago.

A spot where corrosion easily happens.

- [Translator] Between 322 and 320.

- [Narrator] Peter [indistinct] marks the exact location

of each spot of corrosion.

- [Translator] The damage pattern looks pretty much

the same everywhere.

- [Translator] The exterior main girder's affected mainly.

- [Narrator] Rust everywhere on the main girder.

Calls for concern?

- [Translator] No, we're not really worried

because we observe it constantly

and do regular maintenance work,

so we can always guarantee the bridge is in good condition.

- [Narrator] The result of the main inspection,

except for the corrosion,

no further damage to the box girder of the Europa Bridge.

And so the future

of one of the main arteries in Europe remains secure.

Another spectacular bridge.

The extraordinary structure is located nearby

in Switzerland.

In the late 70s,

bridge designers worldwide ignite

the next stage of evolution,

away from pure functionality

towards a more exciting design.

The Ganter Bridge in the Swiss canton of Valais

is probably the most impressive example,

undoubtedly one of the most spectacular

car bridges in the world, spanning the [indistinct]

Surrounded by 4,000 meter high mountains.

[dramatic music]

The Ganter Bridge is part of the Simplon Pass Road

in southern Switzerland.

Before the construction of the bridge,

traffic wound its way along the rugged mountains.

Falling rocks a constant danger,

resulting in many fatal accidents.

The old bridge had served its time.

Since 1980,

traffic goes over the Ganter Bridge.

Because of the mountainous terrain,

countless bridges span the Swiss valleys,

but the Ganter Bridge puts them all to shame.

A complete overhaul of the bridge takes place

every five years.

Civil engineer Thomas Valen and his colleague,

Pierluigi Zatiani know the bridge well

and know what to look for.

First it goes to the heart of the construction,

to the inside of the bridge.

In the section beneath the surface of the road.

Thomas and Pierluigi

penetrated the inside of the reinforced concrete box girder

to a spot that they noticed

during the last inspection five years ago.

[workers speaking foreign language]

The steel reinforcement

within the concrete is susceptible to corrosion.

The inspectors want to ensure that no risk exists

for the construction since maximum safety is imperative.

- [Translator] It hasn't gotten worse,

there hasn't been more leakage,

so the rust has not spread.

- [Narrator] Thomas Valen is relieved.

Only 10 years ago,

the bridge was completely overhauled and renovated.

As far as Thomas is concerned,

this bridge is more than just a connection from A to B.

- [Translator] The bridge is a bit of an accolade

in the civil engineering profession,

and if you are part of the project, involved, you're proud.

- [Translator] These inspections are like

an interactive visit to a museum,

part of historical technology.

You can see what is possible, what you can achieve.

- [Narrator] Construction work begins in 1976.

The major challenge for the designers,

the pillars which are north of the valley.

Because here the slope is not stable.

On the contrary, it is slowly moving downward.

Nevertheless,

the pillars are supposed to permanently support

18,500 cubic meters of concrete and 2,000 tons of steel

on a permanent basis.

The architect is faced with a problem.

How can he anchor these gigantic,

almost 100 meter high pillars on a moving slope?

Regardless, professor Christian Menn accepts the challenge.

He is the most famous bridge builder in Switzerland.

With the Ganter Bridge, he wants to create his masterpiece.

- [Translator] The geology is in fact very important

for the Ganter Bridge.

On one side, you've got rocks and cliffs.

On the other side, the so-called screed, which are moraines.

Very fine material that creeps

so you can't build the foundation there.

- [Narrator] Menn overlays the pillars

in specially designed shafts

that co-migrate with the slope.

The pillars themselves remain on neoprene bearings,

which rarely have to be readjusted on the sliding slope.

The superstructure of the S-shaped road is reinforced

with cast cable pulleys,

a flexible anchor-bearing rigid superstructure,

an ingenious combination.

- [Translator] If the whole thing needs to be moved,

then the superstructure and the carrier

should be relatively stiff.

In a cable-stayed bridge with fine girders,

that is just not that stiff.

And these stiffeners are used as well.

[gentle music]

- [Narrator] The foundations are wider than the pillar

and allow slope movements of up to 60 centimeters.

Inspection of the bearings on which the pillars rest,

one of the most important steps of the inspection.

- [Translator] Really, here you have two movements.

You see that now.

Right now we are 17 centimeters

from the zero position and 15 in this direction.

In 1980, that was considered a sensational achievement.

- [Narrator] But the foundations are exposed

to the extreme weather.

Thomas and Pierluigi encounter damage

which is considerably larger than in the bridge interior.

- [Translator] Strong flaking.

Now we have further spalling of the concrete,

some two centimeters.

The coverage can no longer be guaranteed,

at least not in its entirety.

- [Narrator] And here at 1,500 meters,

there is ice, snow, and salt.

- [Translator] And if we wouldn't do this,

if we just wait for damage to happen,

it gets more expensive and sometimes even irreparable.

- [Narrator] The special foundations

are the backbone of the Ganter Bridge.

They carry the main net burden and volume of traffic

since its opening in 1980.

The life expectancy of the structure

depends on many factors.

High up in the Alps, weather is a problem.

- [Translator] That happens quite often.

- [Narrator] In some places, the outer layer is damaged,

which protects the concrete from the road salt

used against ice accumulation on the bridge.

These sections definitely have to be repaired.

On the concrete cladding of the stabilizing harness,

the expensive protective layer was left out.

Is that going to backfire?

- [Translator] They are in the same condition

as five years ago.

The cracking is the same.

As you can see,

we have the surface covered in fine cracks like a net.

They were visible at the last inspection.

- [Narrator] After two days of inspection,

Thomas Valen gets a first impression

of the condition of Ganter Bridge.

- [Translator] The bridge is actually

in very good condition.

We have normal wear and tear.

Through the inspection system every five years,

damages can be detected in time and repaired.

That way we can catch problems

before more serious damage can occur.

It would be negligent

if you don't do anything for 30 years

and hen check if everything is still okay.

[bright music]

- [Narrator] The Ganter Bridge,

an outstanding example of architecture,

a monument to Swiss engineering.

Nowhere has a balance between function and form been found

and so impressively realized

as at the beginning of the 1980s.,

Later, bridge designers overseas push the envelope

to reach new limits as well.

The Sunshine Skyway Bridge in Florida represents

new cable-stayed design

and is the longest bridge in the western hemisphere.

[dramatic music]

The Sunshine Skyway Bridge is located in the Gulf of Mexico

on Florida's west coast.

The sunshine Skyway spans the Tampa Bay in Florida

from St. Petersburg to Terra Ceia.

Its signature bright yellow represents the Sunshine State.

6:00 AM, the first crew makes its way to the bridge

for inspection.

Due to its exposed position surrounded

by salt water, strong winds, and high air temperatures,

several crews are engaged on a daily basis

in the maintenance of the gigantic bridge.

The crew here focuses on the inspection

and maintenance of the bridge pillars.

At the same time,

there is also a lot of work to be done on the bridge.

Tanel Mullins and Jeff Blair discuss final details

for today's inspection

on top of the Sunshine Skyway.

Then they're on their way.

Their maintenance assignment takes them

to the middle of the cable-stayed concrete bridge

on the four lane highway.

Between St. Petersburg and Terra Ceia,

more than 50,000 vehicles cross the bridge each day.

Tanel Mullins has been working

for years together with his boys,

making sure the bridge withstands the fatigue

that comes with high volume traffic.

- We have a 24/7 response

to emergencies and accidents and those type of things.

Long days, so to speak, or long nights for that matter.

Every day is a new day. Every day is a new challenge.

- [Narrator] Tanel and his crew service the bridge daily,

a necessity to keep the Sunshine Skyway Bridge safe,

which is in the open sea and therefore in salty air.

- We have to basically run across traffic

in order to access anything in the median

or access the to get down inside the bridge.

- [Narrator] Working as a team gives everyone a good feeling

because they look out for each other.

The job is dangerous.

Despite a speed limit of 65 miles per hour,

traffic on the bridge is unpredictable.

Maneuverability is limited on the bridge

because you've got the ocean on either side.

You always gotta be careful, I mean, you know,

it's not too scary if you're watching this,

you really have to watch out and get a big head start on it.

- [Narrator] To get to the stay cables,

the workers must find a gap in the middle

of rush hour traffic on the highway,

and that may take time.

- Let's go.

[dramatic music]

- [Narrator] One of the main problems

of the Sunshine Skyway,

corrosion of the steel in the precast

concrete segmental columns.

Tanel and his crew have repeatedly renovated,

reinforced, and replaced parts.

[tools screeching]

- A bridge this size has a lot of,

even though it's very big,

it has a lot of intricate details

that have to be maintained and watched after.

- [Narrator] The bridge is constantly being serviced

by the crew.

An imperative requirement due to the salty air.

But that is not the only danger in the Gulf of Mexico.

A cautionary tale,

the previous bridge, which stood in almost the same spot,

was rammed by a ship in 1980.

366 meters of the bridge crash into the sea,

along with six cars and a Greyhound bus.

- [Radio] Mayday, mayday, mayday coast guard.

Mayday, mayday, mayday coast guard.

- [Radio] Vessel calling mayday, vessel in distress.

This is United States Coast Guard.

- [Radio] The Skyway Bridge is down.

Get all emergency equipment out of the Skyway Bridge.

The Skyway Bridge is down.

Mayday, emergency situation.

Stop the traffic on that Skyway Bridge.

- [Narrator] 35 people drowned in the Bay.

Only the respective end segments

of the old bridge are left, vigils of the past.

The new Sunshine Skyway Bridge is completed

only seven years after the accident.

The two main pillars upon which the pylons rest

are protected by round manmade islands called dolphins.

[upbeat music]

The current bridge engineer, James Jacobson,

has learned from past shortcomings.

- We wanted to make sure that this would never happen again.

So the new bridge was built

with much stronger pier protection,

these islands surrounding it that will protect

the bridge from being hit in the future by any other ships.

In addition,

the main pilings are surrounded by rock islands

with large boulders that would stop a ship

from ever being able to hit the main columns again.

- [Narrator] The cable stay design allows

wider ships passage and a better redistribution

of forces, even in heavy seas,

strong winds, and hurricanes.

The bridge won't be hit directly

because of the small islands,

which are made of coarse gravel covered

with a steel protective layer and extend

into the seabed of the Tampa Bay

to protect the pillars from all sides.

- Many workers working in harsh conditions

below the water level in these cassons

that were driven deep into the bay bottom.

And then as the bridge was brought up,

they were working high above the bay

adding these pieces together until it finally connected

in the middle and then the bridge was complete.

- [Narrator] Safety during the construction

of a new bridge has top priority.

The choice of design demonstrates this.

It is constructed of concrete and steel cables running along

the center line of the bridge supporting the main span.

It was designed by the Fig and Muller engineering group

and built by the American Bridge Company.

Thanks to the round shape of the protective islands,

the initial impact of a ship collision can be dealt with,

but also the direction of the vessel is changed.

It bounces off the side,

and thus the impact to the island is reduced.

[gentle music]

In addition, 40 small offshore islands

protect the bridge against direct collisions.

According to the engineers,

the bridge can now withstand a collision

with an 87,000 ton ship.

Regardless of new innovations,

the Sunshine Skyway Bridge must be serviced daily

to be able to survive the rough Gulf of Mexico.

Tanel Mullen and his crew know that theirs

is a never ending job, but he loves it.

- The reason I like working on a bridge like this

in the role that I have as a maintenance guy,

it allows you to work out almost in nature.

I mean, you're on top of the Tampa Bay world

so to speak right here.

- [Narrator] An exciting day

with maintenance above and below

one of the most spectacular bridges in the world

comes to an end.

[dramatic music]

Another exceptional sea bridge requiring high maintenance

can be found in Northern Europe.

It is Europe's longest bridge.

We're not just saying that because this bridge

is really long, incredibly long,

long enough to connect two countries.

The Oresund Bridge connects the Danish capital Copenhagen

with Malmo in Sweden.

The Oresund Bridge is one of the largest

infrastructure projects in Europe.

Its construction at sea

only works thanks to a mega construction site

that brings engineers and technology to their limits.

7:00 AM, service start for Christian Norman,

the Technical Director of the bridge.

His shift nearly always starts in the monitoring center.

- Hi Christian. - Hi Marty.

[workers speaking foreign language]

- [Narrator] No bridge has

such an extensive monitoring system

as the Oresund Bridge, and for a good reason.

The Oresund Bridge is a combined road and railway bridge

subject to rigorous deformation criteria.

Traffic loads and weather information must be constantly

measured and evaluated in order to identify

potential hazards such as this traffic collision early on.

The Oresund Bridge is the longest cable-stayed bridge

in the world,

which carries both four traffic lanes

and two railroad tracks.

A total of 30,000 sensors and 256 cameras

not only collect data on traffic and weather,

but also take measurements prior to the vibration effects

of the stay cables.

The nearby Danish airport also requires

the highest safety standards.

Christian Norman scans the entire system

and gets a disturbing warning.

A sensor in one of the tunnels

leading to the bridge reports an error.

- If the whole system is not working,

we cannot hold the temperature down in the port building,

and if the temperature is going to rise,

the electrical systems could overheat

and there will be much bigger problem afterwards.

The worst problem would be that something

had happened with the wind data.

- [Narrator] Christian immediately makes his way

to the site.

On a day like today,

the maintenance team is already on alert.

During bad weather,

the tunnel managers monitor the situation

around the bridge very carefully.

If the wind picks up and develops into a strong storm,

it may even be the case that

they have to temporarily close the bridge.

Christian has arrived at the well secured electronic heart

of the Oresund Bridge.

The entire electrical engineering system

comes together here.

One of the main components

of the 1 billion Euro construction project.

The Oresund Bridge is one of the most monitored bridges

in the world.

Countless kilometers of cables

and wires run together underground.

Pinpointing the cause for concern is often

like trying to find a needle in a haystack.

- Now I have to find out if we have a signal here.

The signal set is open,

so I have to try to adjust it a little bit.

- [Narrator] This time,

Christian finds the error in the cooling

and ventilation system of the tunnel unusually fast.

- Off signal, and now we have the signal on.

It means that we have one fault less here.

- [Narrator] The Oresund Bridge,

the gigantic construction now makes it possible

to drive over land from continental Europe

to Scandinavia and vice versa.

Every day, 19,000 vehicles and 200 trains use the bridge.

But until then, it is a long and difficult road

at the start of construction in 1995.

In the middle of the sea,

a four kilometer long artificial island is built.

One of the bridge ends will finish there

so that the approach path of the Copenhagen Airport

is not disturbed by bridge elements.

Construction manager Lars Pedersen

has struggled from the outset with a lot of resistance.

- When we started, everybody was pessimistic.

People were concerned about the economy,

people were concerned about the time schedule

and the environment.

But it showed out that the ugly duckling

became a beautiful swan in all regards.

- [Narrator] The strategy of Lars Pedersen

and his colleagues,

to finish 90% on land

and then transported by floating cranes out to sea

rather than assemble it on site.

The plan works and the project manages to keep

within the set timeframe.

- There was a lot of protests also during the construction,

but it showed out that there were solutions to things.

To me, the Oresund bridge means something very special,

and to me it will be the most beautiful bridge in the world.

- [Narrator] The over 7.8 kilometer long bridge

spanning the Oresund Sea between Sweden and Denmark

is a maintenance monster.

[conversing in foreign language]

- We have a problem on the Northwest pylon

with the aircraft warning lights.

So we have to make a quick stop and go up to see

what the problem is because it's not flashing.

It has to work 24/7.

- [Narrator] Oresund Bridge

is only five kilometers away from Copenhagen Airport

and air traffic cannot be compromised

under any circumstances.

This is also the reason why one end of the bridge disappears

into a tunnel.

[dramatic music]

But the current problem is not underwater.

200 meters above the strait,

the main pylon's aircraft warning light in the approach path

to Copenhagen Airport is out.

Christian takes the elevator inside the pylons

to the highest point of the bridge.

[alarm siren blaring]

Normally, not only the left and center warning lights

must flash, but also the right one.

It's obviously defective.

The problem is pinpointed.

A protective control has temporarily shut down the light.

Christian has the problem under control in no time.

[upbeat music]

- Yeah, beautiful. Now it works again.

- [Narrator] And while one is up here,

why not take a few minutes

to enjoy the breathtaking scenery?

- It has been that since I've been started working here.

It is so great and so big and everything.

Everybody's out here that works here are great people.

So it's the best job as you can guess.

- [Narrator] The bridge between Copenhagen and Malmo,

one of the most important connections in northern Europe

and one of the most spectacular bridges in the world.

But the latest milestone in road bridges

is in western Europe.

Another cable-stayed structure,

but one like no other on the planet.

It has the highest bridge pier worldwide

and an incredible length of almost 2.5 kilometers.

With its construction, records are broken.

Daily maintenance is an adventure every time.

The Millau Viaduct changes the map of Europe

and currently represents the pinnacle

in road bridge construction.

[dramatic music]

The Millau Viaduct is located in the south of France.

The Millau Viaduct in France, a bridge of superlatives.

It has been built to withstand hurricanes and earthquakes.

It represents a benchmark in cable-stayed construction.

Seven pylons elevate the highway of the viaduct

to a height of up to 245 meters over the Tarn Valley.

As tall as a skyscraper. built in stages.

The pylons of steel reduce the overall load,

making it possible for a minimum of stay cables

that distribute the bridge load over 14 fields.

It's gigantic and to the finest detail

sophisticated design combines centuries

of bridge building expertise.

With its spectacular dimensions.

The Millau Viaduct demands everything from its engineers.

For 12 years,

the French argue about the optimal solution

in terms of aesthetics and feasibility.

[dramatic music]

The A-75, the shortest route between Paris and Barcelona,

one of the main arteries of Europe.

The most spectacular part of the highway

runs through the valley.

Life before the viaduct meant winding roads

and hairpin turns through the valley

slow-moving traffic, and frequent traffic jams,

often a journey of up to two hours.

[bright music]

The solution, the Millau Viaduct,

a road leading you through the air.

Crossing the valley takes 10 minutes now by car.

In 2004, the bridge is finally completed,

a milestone in bridge construction.

Every pylon is supported by a total of 22 struts or stays,

11 on each side.

Inside the stay, there are steel cables.

The tallest pylon measures 343 meters

from the ground to the top.

The Eiffel Tower easily fits underneath

the spectacular construction.

High pylons, wide spans.

Not only is the construction ambitious,

so is regular maintenance.

7:00 AM, Maintenance Supervisor Tiari Visat

and his team start the working day.

They're preparing for a mission at maximum height.

There are problems with the illumination of the bridge.

- [Translator] Can you come please?

We have a problem on top of P2.

- [Narrator] An aircraft warning light has to be replaced.

As luck would have it,

the defective light is at the top of the highest pylon.

- [Translator] So have you got everything we need?

A light replacement, the tools? We have to go up P2.

There's a problem with the light. We have to replace it.

Okay, up we go.

- [Narrator] Tiari will personally replace the light

on the highest of the seven pylons.

Access to the pylon is directly under the road surface.

While traffic rolls over the asphalt above,

the engineers make their way under the highway to the pylon.

A long way to go,

especially when the two of them still have to climb almost

100 meters up to the top of the pylon.

- [Translator] So here we've got to go up pylon number two.

That is physically very strenuous.

After all, it is 87 meters up there.

- [Narrator] The long and difficult ascent begins,

87 meters, and only by ladder.

The men climb up in pairs in case of an accident.

Each pile is hexagonal and extends

below the bridge deck 90 meters.

In the upper part, it branches out into two pillars.

The form repeats itself upside down

over the road up to the cutoff point.

The problem here,

when night falls and darkness descends, danger looms.

The airport Rodez-Marcillac is only 60 kilometers away

from the bridge.

Aircraft taking off and landing

have to be able to see the viaduct.

It's why aircraft warning lights are set

at the top of the pylons.

Should these lights fail,

it could be disastrous for the aircraft.

To make sure this doesn't happen,

the bridge's permanent maintenance team

regularly replace these bulbs.

They don't wait until they actually fail,

but monitor the bulb's service life

and replace them before they go out.

Tiari and his colleagues have been fighting their way

up the pylon for half an hour,

and today, it just happens that the warning light on P2,

the tallest pylon, has to be replaced.

Reaching the top,

Tiari must venture out into the open,

a small platform at a dizzying height

of 343 meters up in the air.

Here is the aircraft warning light.

The bulb must be replaced by the two engineers.

But first, the great view compensates for all that climbing.

- [Translator] Climbing to the top of the pylon

still always produces a special feeling.

There's this incredible view.

- [Narrator] Now begins the trickiest part of the job

for Tiari and his colleague.

At 343 meters, every move must be precise.

The tiniest mistake could be fatal.

Whatever falls from up here

lands on the highway like a speeding bullet.

- [Translator] We are always very focused when we work.

We have to be extremely careful

that nothing slips out of our grasp and falls.

- [Narrator] Up on the platform on bad days,

there can be wind speeds of up to 200 kilometers per hour.

And if a bulb is defective,

the men have to climb up there regardless.

[bright music]

Constructing the bridge is a huge challenge.

Bridge Manager Emmanuel [indistinct] remembers

that deadline pressure is a major factor.

- [Translator] We had three years to build the bridge.

We pushed the traffic lanes together from both sides.

That was very complex and time consuming and involved using

special GPS systems for the very first time

in bridge building.

- [Narrator] The challenge,

pushing the roadway onto the pylons from both sides

of the valley.

Meter for meter, hydronic systems guided both ends

onto each other,

and all that at a height of up to 245 meters.

- [Translator] The traffic lanes were partially undulated.

Those unfamiliar with the work saw that

and said they're crazy, that'll collapse.

- [Narrator] 500 men working around the clock

for three years,

managing to raise 21,000 tons of steel and 206,000 tons

of concrete stretching through the air.

December the 14th, 2004,

it is complete, an historic day.

But work on the bridge is never ending.

Every day, a four man maintenance team is in action.

On the highest bridge pylon in the world,

Tiari and his colleague have worked their way

to the heart of the aircraft warning light device.

The bulb can now be replaced.

[dramatic music]

The view makes up for the stress.

- [Translator] When the job's done,

it's great to have this amazing view.

That makes up for some of the effort, doesn't it, Francois?

- [Translator] Yes, the ascent is always pretty difficult,

but when you're up there, it's simply beautiful.

- [Narrator] The end of a successful working day

in what must be one of the most spectacular workplaces ever,

on top of the tallest bridge pylon on the Millau Viaduct,

one of the most spectacular bridges in the world.