All language subtitles for puorGVM.CAA.462x.VTDH.p0801.egdirB.rebmuH.ehT.6fo6.1.seireS.segdirB.tsetaerG.sniatirB

Britain's iconic bridges,

spanning
our most dramatic landscapes,

have not only linked our island
but made it great.

These are the bridges
that are known around the world,

built by visionaries
like Stevenson and Brunel

who are famous even today.

Look at this!

From the banks of the Tyne
to the mighty Thames,

from the Firth of Forth
to the Menai Strait...

I'm on a journey to discover
how those great bridges were built...

Here we go.

And the sweat and sacrifice
that went into their constructions.

Stopping traffic.

I'll uncover the huge egos,
flawed geniuses and jealous rivalries

behind their creation.

It's as if he'd been airbrushed
from the whole story.

These are Britain's Greatest Bridges.

On the eastern fringes
of the British Isles,

there's an extraordinary structure
that is somewhat forgotten.

It's a record-breaking structure
that changed engineering forever,

and we've been given
special permission to explore it,

from bottom to top.

Wow! My goodness!

This is something special.

It's so high up.

It's nothing apart from these
two cables which disappear off.

This is the Humber Bridge.

Its length from end to end
is more than 2km,

and between the two gigantic towers,

stretches one of the greatest
engineering feats in history.

The suspended central span
is 1,410m long,

and when it opened in 1981,

it was the biggest suspension bridge
on the planet.

Just look
at these two enormous cables,

they're about 70cm thick.

Each of them weighs
over 5,000 tonnes.

Then there's the towers,

the one on I'm stood on here
on the north side,

and the one way off in the distance.

These things are so tall,

they're actually further apart at
the top than they are at the bottom.

And you know why?

Because of the curvature
of the Earth,

that's the scale
we're talking about here.

The whole thing is epic.

For nearly two decades,

this colossal edifice
reigned supreme.

The longest span of
any suspension bridge in the world.

For many, including me,

the Humber Bridge is one of the
most beautiful bridges ever built.

There's an understated simplicity
that I just love.

The way it disguises thousands
of tonnes of concrete and steel,

like a feather floating effortlessly
across the water.

But building this record-breaking
bridge was far from effortless.

It was a severe technical challenge,

born out of an extraordinary
political power struggle.

So just what did it take to build
the longest bridge in the world

right here in Britain?

As with most great bridges,

the story of this one begins
with a stretch of water

that many people
thought unbridgeable -

the wide Humber Estuary.

Formed by the combination
of two great rivers,

the Ouse and the Trent,

and almost 60km long,

this tidal inlet divides
a major industrial region in half.

Let's have a little look
at the lie of the land.

So I've come up the north tower,

so this is the north side
of the estuary.

Off in the distance there,
the city of Kingston upon Hull.

This is Yorkshire.

Across the other side,
away over the expanse of the bridge,

is the south side of the estuary.

That's North Lincolnshire.

And if you look out east,
you've got the town of Grimsby,

and further east,
you're into the North Sea.

Before the bridge was built,

driving from one side of the Humber
to the other

involved a 70-mile road journey
that could take two hours or more.

The only way to cross quicker,

was to ride on Britain's answer
to a Mississippi paddle steamer.

The paddles on the steamer allowed
them to navigate very shallow waters,

but the silty Humber was
so shallow in places,

the ferry still ran aground
from time to time,

stranded in the middle of the estuary
until the tide changed.

Amazingly, decades since
it was put of a job on the Humber

when the bridge opened,

you can still hop aboard
one of the paddle ferries today,

here on the banks
of the River Thames in London.

Now, permanently moored,
and used as a popular bar,

the Tattershall Castle,
as this vessel is known,

is in remarkable condition.

Stepping aboard is like
walking into a long forgotten world.

Now, this is the engine room.

It was built in the 1930s.

If you look you can see
all these beautiful brass fittings,

this great big crank shaft
and connecting rods.

And down here, you can see
where the spindles would be attached,

and there would be another one
on the other side,

and they'd head straight out
to drive the great big paddles

on each side
on the outside of the hull.

Sadly, the paddles have
long since been removed,

but you can see the deck extensions
that once sat above them.

These images show the steamer
in its final days

under the ownership of British Rail.

The Tattershall Castle put in
39 years service on the Humber,

before being brought to London
in 1975.

But the fact that
this old paddle steamer should end up

here on the River Thames
is oddly fitting.

You see, it was right there,

in the Houses of Parliament
behind me,

that this ferry lost its job
on the Humber.

It was a casualty
of a fierce political struggle

that saw the voters of Hull
being offered

what was seen as
an extraordinary election bribe -

a bridge.

A bridge that was set to be
the longest in the world.

When the Humber Bridge opened
in 1981,

it was the longest single-span
suspension bridge ever built,

with a road deck 2.2km long.

This new roadway
connected communities

on opposite banks of the estuary

that used to be 70 miles apart
by road.

Overnight, they became
brand-new neighbours.

But more than that,

this record-breaking bridge
formed the promise of a new future

for this part of Britain.

It would spur the creation of
a new industrial hub for the nation.

But it wasn't quite
for such public-spirited reasons

that the bridge really got built.

It's widely held that it was,
in fact, the result

of some rather more calculated
political game-playing.

Back in the 1960s,

the folk of the Humber towns
had already spent decades

campaigning for a new bridge.

Theirs was the only estuary
in Britain that didn't have one.

But a bridge that could span
this expanse of water

would not only have to be
extremely long,

but also very tall.

There are four major ports
on the Humber

that carry a hefty 13% of
the UK's seaborne trade between them.

With 4,500-tonne cargo ships
regularly passing the bridge,

the deck had to be high enough
to allow them to flow underneath.

But the design also had to
take into account

what goes on under the water.

The Humber Estuary has
a very soft bed,

with deep channels and shallow banks
that can shift over time.

As those deep channels move,

the shipping lanes need
to move with them.

Most kinds of bridge
able to span a river this size,

require a whole series of supports,

leaving only narrow gaps for shipping
that could easily silt up.

But there's one type of design
that needs just two towers.

A suspension bridge could cross
the water in one giant leap,

allowing ships to follow the channels
as they change.

So to keep the full width
of the estuary open,

this bridge had to be
a suspension bridge.

And with the banks
more than 2km apart,

it would be
the longest single-span ever.

Despite their advantages,

suspension bridges are complicated
and, therefore, costly to build.

No-one seemed willing to spend
the kind of money needed.

Then something happened

that would make the expense
of such a construction,

all of a sudden,
worth it to the Government.

This man died.

Henry Solomons MP.

Harold Wilson's Labour Government
was made highly vulnerable

by the death of Mr Solomons.

A by-election for his Hull North seat
was set

for the 27th of January, 1966.

If Labour lost, Wilson would be left
with a majority of just one MP.

For Labour, a win was crucial.

Wilson dispatched his most
experienced political operators

to win over the voters,

including the transport minister,
Barbara Castle.

Mrs Castle stood up to give a speech
to 200 people

crammed into a local school hall.

Everyone expected some kind of road
improvement carrot to be dangled,

but then she came out with six words
that nobody anticipated -

"You will have your Humber Bridge".

Nine days later,
the people of Hull went to the polls,

and here at the city hall,
the votes were counted.

Joseph Kevin McNamara,
Labour, 24,000...

It was a victory for Labour.

The bridge would finally be built.

But six years later,
when Wilson was voted out of office,

there was still no bridge.

Surprisingly,
the man who defeated him,

Conservative
Prime Minister Ted Heath,

revived the scheme.

Heath had plans
for a new industrial county

called Humberside.

It would take in the whole estuary

from Hull to Grimsby, and beyond,

with a new bridge at its heart.

Leading the project would be
the firm of Freeman, Fox & Partners,

run by Sir Ralph Freeman.

Freeman was the world's best
suspension bridge engineer.

His other hits include
the Severn Bridge

and the Forth Road Bridge.

If Sir Ralph could make
this ambitious design a reality,

it would be the pinnacle
of his career.

Ground was finally broken
in July 1972.

If you stand here and look out

over what was the biggest
suspension bridge in the world,

you might have a job puzzling out
just where they started building it.

I mean, how do you get
two enormous cables

weighing 5,000 tonnes,

155m up in the air,

with a 2km road hanging off it?

The answer is to start
where every suspension bridge must,

with two enormous holes
in the ground.

These holes will form the foundations
for the towers.

The towers will then be used
to hold up the suspension cables,

and from those cables,
the road deck will be suspended

from a series
of smaller vertical cables

called hangers.

But it all starts with the holes,

and digging those is not as easy
as it seems.

If you've ever dug a hole
on a beach before,

you know it doesn't take long before
it starts filling up with water.

And what I've created here is
much more of a...

murky pond than any kind of basis

for a 155m suspension bridge tower.

The way to make a dry hole
on a wet beach is to use sheet piles.

These long interlocking strips
of steel are literally hammered

into the ground
to create a curtain of metal.

On the Dutch River,
one of the Humber's tributaries,

Phil Boyes of the Environment Agency
is driving piles into the riverbed

as a flood defence.

As one sheet goes down right next to
the other, they kind of join, do they?

There's a bit of a joint between them?
There is, yeah.

On the edge of each pile,
there's what is called a clutch.

So, one is... it's a curve of steel
one way

and then it's curved
the opposite way on the next pile,

so that helps
the two piles interlock.

And then the vibrating hammer
essentially just vibrates the pile

at a very high frequency

and that's what helps drive
that pile down into the ground.

Essentially, it's using brute force...
It is, yeah.

To get this sheet down
into the ground.

That's very clever.

Now I understand the idea
behind pile driving,

Phil is letting me put the theory
into practice.

So, by doing that we're going to, what, just
build up the pressure in the hydraulics?

Yes, that's the one. Here we go.

Away it goes.

And down it goes, I mean look at it!

What is here just a small flick
of a switch...

triggers an enormous
amount of power over there.

This is high-tech equipment
doing its job.

It's powerful, it's unforgiving,
and it's bloomin' loud.

It's the Gordon Ramsey
of the construction industry.

Here we go, look, that's it.
That's the signal.

Just giving it a quick check there
to make sure it is nice and level.

Everyone's happy. Job well done.

At the Humber Bridge
construction site,

hundreds of tonnes of sheet piles
were driven deep into the riverbed,

forming a dam of steel
around the location of each tower.

That allowed diggers
to excavate the area inside the dam,

without fear of the walls caving in

or the hole filling with water.

Once the hole was deep enough,

the next major step could
take place - filling it in again,

because a strong foundation
made of solid concrete was needed

to support the first
of the two towers.

A year and a half into the project,

they'd now cast a huge slab
of concrete into the hole -

44m long, 16m wide and 11m deep.

It's still there,
hidden away under the beach.

And so, the time had come to begin

the first really revolutionary
feature of the bridge -

a 155m-tall tower,

to be made,
for the first time anywhere

on a long-span suspension bridge,
out of concrete.

Concrete is magic stuff.

When it's first mixed,

it can be poured or moulded
into almost any shape.

And when it sets,
it's as tough as stone.

The Romans were the first
large-scale users of concrete.

They used it on
the world-famous Pantheon in Rome.

Its dome is one of the biggest
in the world made of concrete,

and it's been standing
for nearly 2,000 years.

But suspension bridge towers are subject
to quite different and far greater forces

than most buildings.

The thing was, up until that point,

suspension bridge towers had almost
always been made out of steel,

so the bridge designers
had to be absolutely certain

that a huge concrete tower
would be equivalent in strength,

and the reason they could be
was all to do with these.

Oranges.

The Humber Bridge
is still standing today,

thanks to a French gardener
called Joseph Monier.

It was the 1860s

and Monier worked at
the historic Royal Palace in Paris

where one of his jobs was to
look after the exotic citrus plants.

Every summer, he'd have to move them
from inside their glasshouse

to the gardens outside,

but the concrete pots
they were in kept breaking.

The problem is
that whilst concrete is very strong

under the force of compression,

it's very weak
under the force of tension.

So any sideways pull,

like when a heavy lorry

crosses a suspension bridge,

could cause it to crack apart.

Monier found this same problem

when he tried to drag
his orange pots around the garden,

until he made a simple change
to their design.

Monier discovered

that if he put iron rods
into the concrete as it set,

when it hardened,
it was much stronger.

That simple addition -

adding metal rods
to create reinforced concrete -

totally changed its behaviour.

This new form of concrete

is as strong in tension

as it is in compression,

making it perfect

for almost any kind of structure.

By the middle of the 20th century,

architects and engineers
were finding amazing new ways

to exploit its properties.

The engineers at Freeman Fox wanted
to take that one step further.

They knew using reinforced concrete
instead of steel could save

months of construction time
and millions of pounds

if they could find a way to get it
into place quickly and safely.

Because even if the concrete itself
was up to the job,

most methods of casting it weren't.

A typical way to make
a concrete structure was

to pre-cast it into small pieces

and hoist each one into position
by crane,

one by one.

But that was out of the question

with the kind of heights
they were talking about here.

Hey!

Another option was to cast
the entire structure in-situ,

but you can't build
a 155m-high mould

and pour concrete in from the top.

So, that's when they turned

to another fashionable,
new building technique.

It was called slip forming
and it had proved successful

in building a futuristic hotel
and casino in Las Vegas.

But could Freeman Fox transplant
this technology

from the parched Nevada desert
to the watery world of the Humber?

It was a gamble
they just had to take.

The Humber Suspension Bridge,

with its world record-breaking span
across the Humber Estuary,

it's a triumph of 1970s engineering.

It used new materials,
and groundbreaking methods

and remained the longest
unsupported roadway until 1998.

One of the challenges facing
the bridge's designers at Freeman Fox

was the massive towers
that such a structure needed.

They would be some of the tallest
ever built from concrete,

but most existing methods for pouring
the concrete just weren't suitable...

so they took a punt
on a novel technique.

The technique enabled tall structures
to be built quicker

and more efficiently
than ever before.

It was called slip forming.

Slip forming gained popularity
in the 1960s

after being used to build
a 31-storey tower in Las Vegas

called the Landmark.

Building a giant, 155m-high mould,

then pouring concrete
from the very top

would be technically challenging,

really costly,
and take far too long.

But slip forming needs
only a small mould, about 6m high.

As the lower parts of the new tower
dry and harden,

the mould is shifted, or slipped, up
a few centimetres on jacks.

All the while the concrete is poured
without interruption.

The mould moves continuously upwards,

leaving behind
a single, solid structure.

The technique worked impressively.

The Humber Bridge towers proved

that slip forming is quicker,
cheaper and safer

than just about any other method
of concrete construction.

In the years since, it's become
standard practice around the world

for almost any kind of tower.

If you look here
on one of the Humber towers,

you can see a series
of horizontal lines

where the concrete was poured
a few inches at a time.

It's almost like
it's got a grain to it.

Working constantly,
it took just under six months

to reach the full height,

that's an average of 7.6cm an hour.

I'm meeting John Bailey,

a local man who had a bird's eye view
of this building revolution.

John, you worked
on top of the towers.

What was it like up there?

Initially, it was a little bit scary

because you were going
into the unknown.

You'd never been up
to that height before.

When you get up to over 500 foot,

then things look a little small
from the top,

so, it was, yeah...

Your heart was in your mouth
most of the time.

And so as the towers grew,

the kind of all the infrastructure
here...

Everything was there... went up with it.
Yeah, you even had...

Well, you can see there,
this is the canteen.

This is where the guys would have
their lunch or whatever...

You know, if it rained.

So, what were the conditions like
working on the bridge?

I mean, you were up there
in all weathers, I guess.

If the weather was bad,
you didn't go up.

It was brutal up there, especially
with the wind-chill factor.

You could get down to -20,
30 up there.

Jeez. It was, it was cold.

Some of the things
the guys used to wear.

I know one guy who used to
pinch his wife's tights

because it would... to keep him warm
in the winter.

It was a standing joke, the idea was
if you climbed the tower,

it was 45 minutes
and three cigarettes.

To get from bottom to top.

The North Tower was finished
in May 1974.

Next, they needed to repeat
the slip forming process

and build the South Tower,
this time, in the river itself.

But when engineers prepared
to start work on the foundations,

they discovered a serious problem
with the sheet piles

surrounding the site.

The design called
for this man-made island

for the south tower to sit on.

But unexpectedly strong
tidal currents ruined the sheet piles

they put in to build it,

helping cause
a crippling two-year delay.

Work on the rest of the bridge
relied on both towers being up,

but the sheet piles had to be reset

and the foundations dried out.

Project bosses were desperate
to claw back some time.

Amazingly, with the experience
they gained on the first tower,

and by working round-the-clock,

they had this second tower topped out
in nearly half the time,

increasing their average climb rate
to almost 11cm per hour.

Building the entire bridge
was supposed to take just five years,

but by 1976,
four years into the project,

only the towers were complete.

The next major task was to lift
the suspension cables

up to the top of the towers,

but unless they were
securely fastened at each end,

they would quickly come
straight back down again.

I'm descending
into a tomb-like structure

at the bridge's southern end
called an anchorage.

It's really nothing more

than a 200,000 tonne slab of -
well, you guessed it - concrete.

The titanic weight of this structure

and its partner on the opposite bank

is all that stops the two cables
from crashing into the river.

But buried deep inside the anchorage
is something totally unexpected.

Wow.

I mean, you know
you're coming deep down

because of all the ladders,
they just keep going, but...

I don't think anything prepares you
for this.

Just listen to that echo.

Moo...

In here, it's apparent

that the suspension cables are
not two enormous wires

but actually thousands upon thousands
of small wires,

each just 5mm thick.

Well, you can see

right above me here is
where one of those main cables,

that runs the entire length
of the bridge,

comes in to the anchorage.

And where it comes in,
what was that great big, fat cable

splays out
into 37 different bunches of wires.

And then these rows of orange blocks
behind me

is where each of those bunches
are anchor-pointed

deep down into the concrete.

Anyone who ever said engineering
was dull and ugly

has obviously never seen this.

It's absolutely beautiful.

The 404 wires in each bunch
are hooked onto giant bolts,

each sunk 20m deep
into the concrete wall.

Each of these loops was carried
across the Humber individually.

There are nearly 15,000 lengths
of wire in total.

If you were to drive across
the bridge in a small car,

each of these wires would carry
just about 30g of it.

All modern suspension bridge cables
are made this way for two reasons.

Firstly,
if one of these wires should snap,

there are still 14,947 remaining
to hold the bridge up.

The other reason is that dragging
a 70cm thick, 5,000-tonne cable

to the top of one tower

across a 1.4km gap
to the other tower,

then down the far side
would be impossible.

So, how was it actually done?

To find out,
I'm meeting with Bill Harvey,

one of the engineers
that worked on the job.

Getting those cables up
is just amazing.

I mean, well, we're right under
one of the main cables here.

What you can't see from here is
actually what's inside this sheet.

It's lots and lots
of pieces like that.

Pieces just like that?
It's incredible, isn't it?

I mean, to think that
is what's holding up...

well, us right now, this whole
roadway, all the cars,

all the trucks
that keep thundering past.

Yes.

That's marvellous.

So, the process of actually
getting cables all the way across...

It's called spinning
because they use a wheel

and the wheel is
actually just a pulley.

The curious method of spinning
was invented in the 1840s

by American engineer John Roebling

and used on almost every
major suspension bridge since.

It involves a pulley system
that draws the wires across the span,

pulling them off a huge drum
at one end.

Bill and I are going to recreate
the principal

on a smaller scale, using string.

If you imagine
a five-tonne reel of wire

fastened into the anchorage.

So this is me
over on, let's say, the north...

Over on the north bank.

And then a spinning
wheel pulling it.

So I run this right across... Right
across the river... across the estuary...

And you'll see how fast
this is unreeling. OK, yeah.

And then it gets looped there.

And those bits get adjusted.
Yeah.

And then another loop is taken.

So actually in that one journey
across,

I've brought over
two strands of wire.

And, actually, there are two wires
on the spinning wheel as well,

so you've taken four
and then you take another four.

Wow, so this speeds things up hugely.
Yeah.

And then when you've done
that 101 times -

and there's 404 wires -

you've got what's called a strand,
and there are 37 strands up there.

How long would that...?

It's going to take about 15 minutes
to do a trip,

done thousands
and thousands of times.

To build up... Yeah.

This great big cable
that we've got here now.

And the guys who are working here
just have to stand here

and maybe stand in the middle
of the river on the catwalk

and catch the wires as they go past
and anchor them.

So, you'd have guys dotted along.
All the way along.

Just to kind of make sure
and guide it and... Yeah.

Make sure everything is
going correctly? Yeah.

And they'd be just stood up there,
what, all day long? All day long.

Standing on that.

Even though four wires could be spun
in just 15 minutes,

it took 22 months to finish
this part of the job.

In October 1979,

the last and most complicated
major process could finally begin -

erecting the 21,000-tonne roadway,
the deck.

This, of course,
is what it's all about.

Everything else - the towers,
the cables and the anchorages -

all exist just to carry this ribbon
of highway across the water.

You might think
that once the deck was in place

the whole suspension bridge
would be solid as a rock,

but that's where you'd be wrong.

To see how much the bridge moves,

even on a relatively calm day
like today,

just watch this coin.

I've popped it down there,

right up against
the edge of this expansion joint,

which connects
the main bridge deck behind me

and the side span there.

Look at it go.
You can see it's moving.

That's a good 2 or 3cm there already,

and it's the bridge deck where I am
on this side that's moving.

It's the gentle flex and sway
of the bridge in the wind

and with heavy traffic,

it's almost like
it's breathing in and out.

As cars and trucks
thunder over the bridge,

they cause the deck
to jiggle a bit.

But the bridge has to cope with
a far greater force than traffic -

the wind.

And when the wind picks up,

movement in the structure
is essential.

Imagine a tree and a brick wall
in a gale force wind.

A tree bends and flexes,

it's much more likely
to remain standing.

The brick wall acts like
a huge sail,

takes the full force of the wind

and blows down much more easily.

Likewise, with a suspension bridge,

a bit of flex and sway
is a good thing.

But if you get your sums wrong,

a bit of sway can turn into something
much more extreme

and the whole bridge
could come crashing down.

As slender and as elegant
as it may seem from afar,

it's not until you get right up under
the bridge deck, like I am here now,

that you get a true sense
of the size

and the strength of this thing.

It's actually quite intimidating.

Like some kind of
ridiculous space ship

slowly drifting overhead.

Lifting the 17,000-tonne steel
road deck into position in 1979

and keeping it there forever
was going to be a serious challenge.

That's because suspension bridges
have an invisible enemy -

the wind.

To resist the force of gales,

all of them are designed
to allow sway,

but one chilling lesson
from history illustrates

how this necessary flexibility
can go badly wrong.

In 1940, a suspension bridge
across the Tacoma Narrows,

just outside the US City of Seattle,

began to swing
in a way no-one intended.

Even before the bridge was finished,

it would buck like a bronco
in high winds.

Construction workers
nicknamed her Galloping Gertie.

Eventually, this curious ripple
turned into a full blown wave

and just four months after it opened,

the entire bridge ripped
itself apart.

There was something about the design
of the roadway

on the Tacoma Narrows Bridge

that magnified the way it behaved
in the wind.

Something the designers on
this bridge had to completely avoid,

and the best way to see how
they did it is by going down in here.

I'm going inside the bridge deck...

So, you leave the day light behind,

coming right down
into this huge, cavernous void.

And it's noisy too with the cars
and trucks going overhead.

They're literally right overhead,
just there.

This is the middle
of the bridge deck.

It's a series of these
vast, hollow, steel boxes,

which continue for a kilometre
in that direction,

along to the north side of the river,

and then another kilometre
all the way down

back in that direction, too,
over to the south bank.

It's really odd down here.

Each one of these boxes
was pre-fabricated on land,

but getting them into place
was no easy feat.

Starting at the dead centre
of the bridge,

they were floated into position,

then hoisted one by one
with huge cranes,

which themselves hung off
the suspension cables.

Each box was then welded
to its neighbours

to form a continuous deck,

and it's the shape of that deck
which ensures the Humber Bridge

will never gallop like Gertie.

Along the entire length
of the bridge deck,

it's flat here in the centre
above and below me,

and then it slopes away
at the sides.

You can see it much better
on this model here.

So underneath,
it's shaped like a saucer,

and over the top, it's shaped,
well, like an upside down saucer.

Compare that then to this model here
of the bridge deck

of the ill-fated
Tacoma Narrows Bridge.

You can see they're very different.

This one is much squarer

and it's got these solid
side barriers all the way along.

So, let's see what happens to this
with a little bit of wind.

Now, you might expect the bridge deck
just to be pushed away by the fan

and kind of stay there
until I turn it off,

but give it a sec.

It starts to sway gradually,

but it doesn't take long

for the Tacoma model
to waggle erratically.

But look at that.

It's going absolutely berserk,
it's osculating back and forth.

It's a phenomena called flutter.

At Tacoma, a strong wind pushed
the bridge to one side,

lifting it slightly.

But gravity and tension
in the cables pulled it back down

and, rather like a playground swing,
up the other way.

The wind then amplified
this movement,

pushing it further
in the same direction,

then gravity and tension
pulled it back even harder.

The back-and-forth motion got
stronger and higher with each swing

until the bridge failed.

Change the design
of the bridge deck and watch this...

It's the same fan,
it's the same springs.

Let's see what happens.

This model is much more
streamlined in shape,

allowing the air to flow over it
far more smoothly.

Not much so far.

But it does something else
that's remarkably clever.

It's the difference in lengths
between the lower and upper deck

that has the strange effect
of lowering the air pressure

under here compared to on top.

Now, effectively, that forces
the bridge deck downwards,

pulling on the suspension cables.

The bridge is bracing itself
into the wind,

and the windier it gets,

the more stable the bridge becomes.

But during the complex process
of assembling the deck,

it was anything but stable.

And in March 1980, disaster struck.

At the north end of the bridge,

one of the 40-tonne cranes
broke loose

and tumbled 70m down
on to the incomplete roadway.

The joints ripped apart,

leaving two boxes dangling
precariously.

The Hull Daily Mail reported
the dramatic accident,

which happened just up here
behind me.

Saying, "A man was hanging on
for his life."

And that "the sections
were swinging like seesaws",

"hitting each other with the sound
like a clap of thunder."

It was a miracle nobody was killed

and, amazingly, the damage done
was minimal,

but the whole incident
was a very close call.

What could have been
a catastrophic disaster

only set the timescale back
by a few months.

In December 1980,

the final box was lifted into place,

completing the span.

The mighty Humber was bridged
at last,

but it came at quite a cost -

£151 million in total.

What's more, it had taken nine years
instead of five

and thanks to the rocketing inflation
of the '70s,

it was £81 million over budget.

Some people criticised the bridge
as a white elephant,

a bridge from nowhere to nowhere,

that should never really
have been built.

Despite all that,

this structure was celebrated
as a national achievement,

the latest in a long line of groundbreaking
British engineering landmarks.

And no less a person than her
Majesty the Queen opened the bridge

on the 17th July 1981.

I'm meeting Rachel Stainforth,

who was there that day,
aged just six.

So, the Humber Bridge has been here
ever since you can remember, Rachel.

It has. It's been a huge
instrumental part of our family.

At the time, my grandad was chairman
of the Humber Bridge Board

and my nan was Lord Mayor of Hull,
so, because I was in the family,

I got asked to give
the official bouquet to the Queen

on the opening of the Humber Bridge,
so I was six at the time, I think.

And on the day, did it all go well?

I did have a bit of stage fright
at the beginning

and so I had to have a nudge and said,
you know, "Get on with it" sort of thing.

And so, I did that
and she was very pleasant.

I think I looked at my grandad
the whole time and not her,

but, yeah, it was... it was
a really good day.

I think now, you know,
as years have gone by

that it's very much a focal point
of the city

and in the people of Hull's,
their hearts.

Her Majesty made
the first official crossing.

Behind her, eager motorists queued up
for their first turn.

The toll charge - £1.

Do you get a free toll pass? No.

No, 'fraid not.
Even my grandad didn't.

Although he was the first person,

he was the first toll-paying car
to go over.

OK, very good. Yeah. Very good.

The Humber Bridge is perhaps
a bit forgotten about,

slightly off the beaten track
of Britain's motorway network,

but we should remember that,
here in the UK,

we have a world record-breaking
structure,

what was for 17 years,

the longest single-span
suspension bridge on the planet.

And it is a bridge to be proud of

and to boast about

because we made it
and we made it here.

Captions by Red Bee Media
SBS Australia 2019