All language subtitles for How.Did.They.Build.That.2021.S02E07.Steep.and.Stunning.1080p.WEB.h264-CAFFEiNE_track3_[eng]

[Male Narrator] How do engineers
building the steepest railway

in the world
overcome impossible odds

and tunnel through a freezing
cold rock face?

[Bruno] It was blocked and then
we had really sleepless nights.

[Narrator] What happens when a
145-year-old building

goes under the knife of an
expert architect?

[Daniel]
It's like a brain surgery.

You have to have the scalpel and
all the precision instruments.

[Narrator] And how do engineers,
building a 700-foot luxury

apartment block,
face down a monster storm?

[Kevin] Unfortunately, we were
at the worst part of the build

when that hurricane came.

[Narrator] This is the age
of the extraordinary.

[Hayley] It's like one
of those insect-eating plants,

only enormous and white.

[Narrator]
Where ingenious engineers have

unleashed unchecked creativity.

Now their secrets are revealed.

As we discover the inside
stories of their construction.

[Corina]
This is an incredible feat

of planning and engineering.

[Narrator] To try and understand
"How Did They Build That?"

To the beautiful mountains
of Switzerland now

and a challenging and innovative
construction project that really

puts the fun in funicular.

Do you even know
what a funicular is?

No? Well, stick around.

With tunnels cut
through solid rock,

and maximum gradients of 110%,

it's the world's
steepest mountain railway.

Naturally,
this being Switzerland,

the design is sweet
as chocolate.

[Narrator] The Swiss Alps.

Home to 48 of Europe's
highest peaks,

each over 13,000 feet tall,

it offers some of the
continent's best winter

skiing and mountaineering.

Getting over 11 million people
up the slopes here every year,

is a serious business involving
251 cable cars,

129 gondolas,
and 42 funicular railways.

In 2012,
more than 500 years after

the first funicular was built,
work started on a new one.

It would cost $57 million
and run two years overschedule,

but it also changed the face
of the funicular forever.

[Hayley] You think,
is it a train?

Is it an elevator?

In some ways, it's both.

[Narrator] The team had to
tunnel through sheer rock

to create the steepest railway
in the world.

And if that wasn't hard enough,

the carriages had to adjust
to gradients from horizontal

to 110%.

[Corina] This thing has
to go from dead flat

to nearly vertical without
tipping over passengers

halfway up.

[Narrator] Capable of carrying
3,000 passengers an hour,

at speeds of 32 feet per second,

covering 2,500 feet of altitude
in three minutes,

this is the
Stoosbahn Funicular Railway.

So how did they build it?

The picturesque Swiss mountain
village of Stoos

lies at an altitude
of 4,000 feet

with stunning views
over Lake Lucerne.

Like many Alpine villages,

it attracted wealthy Europeans
in the 19th century.

But it wasn't until
after the first world war,

when sports like tobogganing and
downhill-skiing became popular,

the tourism really took off.

Mountain resorts needed
efficient transport systems

up and down the steep slopes,
in all weather.

And funicular railways
were the perfect solution.

[Corina] The original Swiss
funiculars of the 1900s

were powered by filling a tank
in the car at the top

of the mountain with water.

Then gravity would
bring it down to the bottom

and pull the bottom one up.

Simple, ingenious
and sustainable.

[Narrator] Funicular railways
solved the problem of carrying

passengers up steep slopes
by pulling the carriages up

with a single cable,
looped over a pulley at the top.

As one car descends, the other
is pulled up at equal speed.

And because they're
counterbalanced the pulley

only needs to lift the excess
weight of the passengers,

which makes the whole system
just incredibly efficient.

[Narrator] In 1933, the tiny
village of Stoos

opened its first funicular,

which not only brought
in the tourists,

but was also the
main access into

and out of this car-free resort.

70 years later, the Alpine
village wants to be better

connected to the valley below.

[Corina] Even if that
means building the world's

steepest funicular railway.

[Narrator] One that will take
the most direct route,

straight up the north face
of the mountain.

It comes with some of the
toughest terrain imaginable

in gradients of 110%.

[Corina] A 1% gradient
means that if you move

100 feet forward, you're gonna
gain one foot in elevation.

So a 110% gradient means that
for every 100 feet you go,

you're goingn to be climbing
upwards 110 feet.

So in other words,
it's really, really steep.

[Narrator] To carry passengers
up and down this mountain,

the engineers will need
to design and build the steepest

funicular railway on the planet
embracing some old-school

funicular tricks while coming up
with some brand new ones.

The plan is for the new
funicular to link Stoos

with the town of Schwyz
in the valley below.

The route will climb
2,500 feet in altitude,

on a single track
that's over a mile long.

Three tunnels will be carved
through the mountain

at some of the steepest
gradients ever attempted,

48 degrees.

At either end,
bridges will connect the near

vertical mountain to
horizontal station platforms.

And engineers will have to
design revolutionary carriages

able to adjust to that using
radical hydraulic engineering.

Reinventing a tried and tested
transport system is one thing,

engineering and building it
is another.

At the start,
we tried to understand would it

be possible this steepness
to manage?

Is it possible from a
technical point of view?

And what would it cost about?

[Narrator] The first challenge
Bruno and his team face

is excavating a straight route
up the mountain.

In 2014, work begins on
the first of three tunnels.

They turn to an innovative form
of drilling originally used

to create ventilation shafts in
mines called raise boring.

[Ellie] Raise boring is most
often used where you have

to create a vertical tunnel.

First you drill downwards
with a smaller pilot drill

until it emerges at the bottom,
then to that you add a bigger

drill head and pull it back up,
widening the hole.

The benefit is that your waste
drops out of the bottom

of the hole on its own.

And that saves
a lot of shoveling.

[Narrator] The team expects
excavating the initial

10-inch pilot holes
to take five days.

But part way through,
the drill piece breaks

bringing the project to a halt.

The rock formation goes down
and up on the other side.

But here it turns.

And in this area,
it's very difficult.

Unfortunately,
when they made the pilot hole

which was 25 centimeters,
it was blocked.

And then we had really
sleepless nights.

What's going on now?
Then it was one year blocked.

That was really a very,
very difficult situation.

[Narrator] The project is
already a year behind schedule

and they haven't even started
building the actual railway.

[Narrator] In Stoosbahn after
a very, very long wait,

the drill bit needed to bore
the funicular railway tunnels

is repaired.

Work restarts and the team
hold their breath waiting

for the drill to break through
the rockface at the bottom.

At the last day,

I saw the responsible machinery
employee was very nervous.

And I ask him,
why are you so nervous?

He says, blocked again.

No, no, no. Listen.
Look, look, look, look.

And after five minutes came
water, water, water out

of the of the wall, water.

And then came the rest out.

And it was really,
it was like a baby's born.

[Narrator]
A year behind schedule,

the team resumes excavating
30 feet of tunnel per week,

blasting the primary holes,

and enlarging them with a
special boring machine,

before coating
and sealing them with concrete.

This is precarious work.

For a lot of the time you're
working in freezing conditions.

You might be on extreme slopes,
and with the risk of rockfalls

or avalanches at any given time.

[Bruno]For the workers,
they had,

sometimes we worked
24 hours a day.

That was a huge challenge
to guarantee this safety.

[Narrator] Finally,
in February 2017,

three tunnels totaling 1,900 ft.
In length are finished.

The tunnels may be complete,

but the engineers' challenges
are far from over.

Next, they need to create a
carriage system that can handle

the extreme changes in gradient,

from steep mountain
to flat station platform.

[Ellie] With most traditional
funiculars the cars are raked

at a fixed angle, all the way
from the bottom to the top.

But with this system they
have to go from zero degrees

up to 48 degrees, and then
back to zero degrees again.

[Narrator] The man charged
with designing carriages

that can do that,
is engineer Niklaus Moser.

The solution comes to him
one night in his kitchen.

[Nicholas] I was at home, and of
course, I was drinking a beer,

can of beer.

And uh, as time goes by,
this can gets empty

and I just put it down
and rotated it.

[Narrator] Nicholas's empty beer
can inspires a futuristic,

barrel-like design
for the carriages.

It will feature
level-adjusting cabins

that are always horizontal,

however steep
the dizzying incline.

A hydraulic piston
within the chassis

continually rotates the cabins
to remain horizontal,

so the 34 passengers in each pod
can move around freely.

The exterior steel
and glass shell means

they also enjoy unobstructed,
panoramic views of the valley

and mountains.

And they say no good can come
from drinking beer.

[Narrator] Five years after
construction began,

the revolutionary Stoosbahn
Funicular is almost operational.

The team has one final check,

stress testing the
prototype carriage systems

at extreme gradients.

[Nicholas] We tested it.

We were rotating
and do all the functional tests.

We lift it up
in this 110% slope.

It was a very, very nervous time

and a very,
very challenging time.

[Narrator] The radical funicular
carriage system achieves what

many thought was impossible.

Under test conditions the
interior barrel-like cabins

rotate horizontally
at gradients of 110%,

and then back to zero again
on the flats.

There were some small hiccups.

This is pretty normal,
fine-tuning, et cetera.

Some modifications
had to be done.

[Narrator] It's now time
for the first test run

of both carriages at once.

Unlike the earliest funicular
railways where the carriages

ran on two separate tracks,
here, there's only one.

So how do they pass?

The narrowest system has both
cars on the same tracks.

And they only split into two
when they pass each other

at the midway point.

[Narrator] This very simple
system was invented in 1879

by Swiss mechanical engineer,
Carl Roman Abt.

At the heart of it
is a wheel with two rims.

If this is fitted
on the outside track

and wheels without rims are
fitted on the inside,

when the track splits in two
it guides the carriage onto the

right-hand track and then back.

[Nicholas] It pulls them out
automatically to the outside

and guides them back in.

So that's called
the Abt passing loop.

[Narrator] That's the theory,
but in practice the first run

on a new track and passing loop
is always a nervous time.

[Bruno] I had a dream that
when first times both wagons

cross in the middle

that it would be not
in the middle

and then I waked up.

[Narrator] The teams
calculations of cable length

and tensioning are the
difference between

the cars passing safely
or colliding.

We had a little bit, we have
been a little bit nervous

because it's a prototype.

But then when it happens first
that both crossed in the middle,

it was in the middle, so that
was a really exciting moment.

[Narrator] Against the odds,
on December 17th, 2017,

the new Stoosbahn Funicular
Railway opens to the public.

Two years overschedule and about
30 million dollars over budget,

the build may not have run
quite like clockwork,

but within months Stoos,
with its incredible new railway

is voted one of the top tourist
destinations on the planet.

[music]

You want to build a tower,
the most futuristic,

state-of-the-art residence
in downtown Miami.

Its design will require
one of the world's most

avant-garde architects
to push the limits of what

even they think is possible.

You'll be using a
concrete, glass-fiber hybrid

that's never been used
in a project like this before.

Anything else?

Oh yeah, a hurricane
is due to hit

right in the middle of
construction.

So what do you do?

You get buildin', that's what.

[music]

[Narrator] Miami Florida,

where South Beach
with its sun, sea and sand

has long been a playground
for the super rich.

But there's a new kid
on the block downtown

that's really turning heads.

Here, a clever developer
with a visionary architect

came together
and transformed the skyline

with an extraordinary
700-foot-tall tower.

They hoped it would
send the price of property

up there with it.

[Corina] At up to 25 million
bucks for an apartment,

this is definitely a place
for the super rich.

[Narrator]
But the stakes were high.

They were gambling on a radical
inside-out structural idea,

never tried on this scale

They all thought we were crazy.

[Narrator]
If that wasn't enough,

a major hurricane
threatened the entire build.

I'm sometimes shocked
that this was done.

[Joe] There was no turning
back once we started

building this thing.
We had to make it work

[Narrator] This tower named
the 1000 Museum

forced engineers and architects
on a journey into the unknown.

So how did they build it?

[Narrator] Miami's South Beach
has long been a destination

synonymous with luxury.

A city known
for its showing off,

houses here have sold
for over $75 million.

Get it right
with your developments,

you can make some serious money.

But in 2012,

land around South Beach is so
eye-wateringly expensive,

that developers
are looking elsewhere.

Kevin Venger thinks the time
is right to bring that

million dollar price tag
to a largely forgotten bit

of downtown Miami.

Better known for its museums
than its luxury penthouses,

Kevin's got a dream of turning
it into a new millionaires row.

Downtown, its location is
in proximity to everything.

This site, has unparalleled
views of South Beach,

the waters, the ocean.

[Narrator] So Kevin's plan is to
build a residential tower block

and entice in the glitterati.

To do that, he decides on a
skyscraper that's going to be

like nothing else on earth.

It's a huge gamble
because if they don't come,

it could be financial ruin.

[Patrik] The ambition was
to lift the market

on that side of Miami

and bring a kind of quality
of architecture and lifestyle,

so that they can actually
catch South Beach prices.

[Narrator] Right now though,
Kevin has an ugly, one-acre plot

opposite Museum Park.

But he has a dream.

To make it a reality,
he turns to Dame Zaha Hadid,

one of the world's most
visionary architects,

whose extraordinary buildings
from the Antwerp Port Authority

to the Quan Zu Opera House,

never fail to stop people
in their tracks.

Here on the site
of an old gas station,

she's going to have
to work some serious magic

if she wants to wow the world

Zaha's designs around the world

are just so unique
and different.

We knew we were going
to have a really amazing tower

that was going to change the
skyline in Miami forever.

[Narrator] Zaha and the team
come up with a revolutionary

design solution,

creating a tower block
that is strong enough

to survive Florida's hurricanes,

but also doesn't need the normal
columns inside to hold it up.

It will start with building
super-sized foundations

to support the building,
even on the soft Floridian soil.

Then instead of the normal
skeleton inside the tower

with concrete and steel columns
giving strength,

the building will be wrapped
in an exoskeleton of glass fiber

reinforced concrete.

This will allow uninterrupted
spaces inside,

stunning views out,
and the sharpest of finishes

appropriate for a block that
comes complete with a helipad

for its uber-rich owners
to pay a flying visit.

It has also, never been
done like this before.

The design really
gave us column-free

interior space.

With column-free interior space,

you can create
amazing floor plans.

[Narrator] Zaha's radical
designs have a reputation for

being notoriously hard to build.

And with an exoskeleton system
that's never been tried before,

this one is going
to be no exception.

[Luis] The first thing that
popped into our heads is like,

yeah, we can make
it work on paper,

but how are we going
to build this?

Because traditional
construction techniques

would not be appropriate
for a structure like this.

No one had ever built
anything like this before.

I knew this was going to be a

super challenging project,
something nobody ever did.

I knew it was
gonna be tough job.

I knew it was
gonna be a long job.

[Narrator] In December 2014,
work begins on site.

And the first challenge
the engineers face

is laying the foundations
for the 63-story tower.

The site itself,
previously a gas station,

isn't huge

and butts up to its neighbours.

And unlike say New York
where stick a spade in,

you're likely to hit granite,

here it's sandy soil
for a long, long way down.

[Kevin] You have to be much more
conscious about the settlement

of the project,
so you don't have any issues

with your neighboring
properties.

[Narrator] The team has
to make sure that the

foundations will be solid,

and that the tower won't
simply start sinking.

So the engineers
decide to go deep.

[Luis] By going deeper,
we would go into more

competent soil or rock,

which would end up minimizing
the amount of settlement

that the building experienced.

They actually hit a record
going 184 feet.

[Luis] The foundations ended up
being the deepest foundations

that were ever done in Miami.

[Narrator] And the record
breaking doesn't stop there,

because now they've
found solid ground,

the next step is
pouring the foundations,

an incredible
10,000 cubic yards of concrete,

which has to be done in one go.

It takes some
serious organization.

But 24 hours later,
the job is done.

[Luis] As that last
truck is pulling away,

you get a sense of relief.

It's like, ah, okay, we're done.

No, but then reality kicks in.

It's like all we did was
just set the foundation.

We still have 60 more
floors to build.

[Narrator] And this
is where the real

engineering challenge begins.

The developers want
their high-end apartments

to go big on space

with virtually
no internal columns.

To do this,
the designers come up

with a ground-breaking,
new exoskeleton that's

both strong enough to hold up
the entire building

and beautiful without the
need for any cladding.

[Corina] On a skyscraper,
the concrete core in its center

provides its main structural
support and stability.

The exoskeleton flips
that idea on its head

because it gives
that vital support

from the outside
of the building.

Just like a scorpion
or a cockroach,

that hard, outer shell
holds its body together.

Its a win-win for developers
because it means you can half

the size of the central
structural core.

You use less concrete
and you get to increase

the internal floor space.

Basically, you get more bang
for your buck.

[Narrator] All good in theory,
but how do you construct

a vast 700-foot-tall exoskeleton
that can bear the weight

of the building,
while showing off designer

Zaha's free-flowing curves?

There's only so many materials
that you can use in order

to get that exoskeleton
to achieve her design.

[Narrator]
From the 15th floor up,

the curving exoskeleton
becomes more intricate.

It needs to be built
from something stronger,

so the skeleton can be thinner.

They hit upon an innovative
material never before seen

on a US skyscraper called
glass fiber reinforced concrete

or GFRC.

[Luis] You might ask yourself,

how is it that you're
reinforcing concrete with glass?

Well, it has a high
strength in tension,

so it starts to mimic
the behavior of steel.

[Narrator] When you add fibers
of glass to concrete,

not only do you get something
that's super strong,

but also it can be formed into
almost any shape imaginable.

Glass fiber reinforced concrete
is essential for achieving

the clean, free-flowing curves
that Zara Hadid is famous for.

Because it uses
prefabricated panels,

you can get razor-sharp edges
that you just can't get if

you're pouring concrete on site.

[Narrator] Normally, you create
shapes in concrete by building

a mold called formwork made
from something like plywood.

You fill it with
steel-reinforced concrete

and when it's set,
you take the formwork away.

But this new technique is
literally a high-wire act

for the builders.

The mold is created from glass
fiber reinforced concrete

that is also going to be
the final exterior finish.

It should look stunning
and be extraordinarily strong.

That's if everything
goes to plan

because none of the construction
crew has ever done anything

like this before.

I knew this was gonna
be a challenge.

[Luis] The most nerve-wracking
moment that we experienced

on the project is when we were
going to see GFRC formwork

being used for the main
structure of the building

for the first time anywhere.

[Narrator] With just
half an inch of tolerance

built into the panels,

fitting them is going to be
anything but straightforward.

[Kevin] They all
thought we were crazy.

They said, oh, you guys are,
this is crazy.

We're never gonna be able to
handle the product.

We're never gonna be able
to keep up with this.

This is a whole new thing.

It took a learning
curve for sure.

[Patrik] I think the contractors
were swearing against us,

you know,
each panel took quite a while,

but it matters.
It's really beautiful.

[Luis] That was a
huge sense of relief

because we had 50 floors
more of this to go.

[Narrator] Barely is the
exoskeleton finished

before mother nature throws a
very dangerous curveball.

In August 2017, Hurricane Irma
is predicted to hit Miami.

Bad enough
for a finished building.

Right now,
it's potentially catastrophic.

Unfortunately, we were at
the worst part of the build

when that hurricane came.

That's the real test for a
building for a first time.

We had finishes going up the
building in the lower floors,

glass going up
in the middle floors

and the tower at the top,
wide open.

[Joe] Cranes were getting taken
down from this hurricane.

You know in
a couple of locations,

actually pretty close to here.

It's a gut shot that you
just hope that you just

have some water damage
and some minor issues.

[music]

[Narrator] Next,
Hurricane Irma makes landfall.

[Narrator] In Miami,
the team are two thirds

of the way through
building the 1000 Museum.

When on September 9, 2017,
Hurricane Irma makes landfall.

Six-foot storm surges
flood the coast.

Winds over 150 miles per hour
batter the city.

It causes over $25 billion worth
of damage across the Gulf.

But somehow, miraculously,

the 1,000 Museum building
weathers the storm.

There was very little damage
from that hurricane.

We got off lucky.

[Narrator] The team gets to work
finishing the final floors

of the tower.

All of the earlier drama
fades away under sunnier skies,

and the rest of the build comes
off without a hitch.

After four and a half years
of sweat and tears,

Zaha Hadid's visionary
skyscraper is at last complete.

Outside, Miami's latest
ultra-futuristic addition

transforms the city's skyline.

While inside, the exoskeleton
has also done its job,

leaving uninterrupted eyelines
and barely a column in sight.

The design sceptics thought it
couldn't be done really is

and it's breathtaking.

All of the units have 10-foot
high ceilings

and all glass wrapping
around gives you right away

when you walk in water views

and a lot of light coming
into your living room.

I love bringing people up here.

Seeing what we've achieved

here is a huge sense
of accomplishment.

[Joe] This one is
probably the best building

that I've ever built
in my career in it

and the toughest.

[Patrik] The workers themselves,
they loved the challenge.

It was a kind of bonding
experience of,

creating something
extraordinary.

I have an extreme sense
of pride every time

I look at the Miami skyline.

1,000 Museum stands out
like the pinnacle of

all the other high-rises.

There's nothing like it
else in the world

[Narrator]
A developer took a massive risk.

An architect pushed
the boundaries,

and a construction team
went the extra mile.

The 1,000 Museum is a true
testament to how embracing

the revolutionary
can build the extraordinary.

[music]

To Germany now where
deconstructivism is transforming

the face of the historic
city of Dresden.

In this case, a 135-year-old,

neo-classical palace
and what appears to be

a crystal-shard rocketship
falling from space.

The result, I am sure you will
agree, is out of this world.

[Narrator] Built in 1876, this
building has been an armory,

an Army museum, a Nazi museum

and a Soviet museum

before closing following the
reunification of Germany.

Then 15 years later,

it rose like a
phoenix from the ashes

to become one of the country's
most extraordinary buildings.

This huge 21st century
glass and steel arrowhead

seems to just penetrate
this historic building.

[Narrator] An architect
with an idea to transform

the traditional
into something completely fresh.

[Daniel] It's like
in a heart transplant.

You're changing
the heart of a building.

[Narrator] Opened old wounds
among the local population.

[Narrator] It took 15,000 tons
of glass, concrete, and steel.

Some serious
precision engineering

and seven years.

This is the Bundeswehr Museum
of Military History.

So how did they build it?

[music]

[Narrator] Until World War Two,
Dresden was considered

so splendid it was known
as the jewel box.

Then in February 1945, the city
was fire bombed by the allies.

25,000 inhabitants
lost their lives

and little remained,

except, somewhat ironically,

the military museum,
which was unscathed.

Following the war,
Dresden was under Soviet control

and the museum was used
to tell the story of warfare

from a Soviet perspective.

But with the fall
of the Berlin Wall in 1989,

its mission became unclear
and its doors were closed.

15 years later,

historians started to seek
new ways to frame Germany's

dark, military past.

[Narrator] In 2001,

the city decides the
old Dresden building

will become Germany's
biggest and most important

military history museum,

but it needs
a radical reinvention

to make it fit for purpose.

[music]

[Narrator] Next they have little
idea how radically different

it's going to be.

[music]

[Narrator] In Germany,

plans are underway
to create a museum,

which will tell its
military history in a

radically, revamped building
in the city of Dresden.

Architect, Daniel Liebskind is
known for his daring approach

to sensitive projects,

such as Berlin's Jewish Museum

and the World Trade Center
memorial site.

He pitches for the Dresden job.

[Ellie] To create a space
that is appropriate

for the complexity
and sometimes incredibly

dark history
of Germany's military

is a monumental design task.

Daniel Liebskind is perhaps
one of only a few

capable of taking this on.

[Narrator] As a Polish American
of Jewish descent,

this project strikes
a chord with Daniel.

What drew me to the
project is the importance

of military history.

You know, all the wars,
World War One, World War Two,

the millions of dead.

That's very interesting
to address it,

to think about it
and to create a building

that is contemporary
and that speaks to that history.

[Narrator]
Daniel's architectural vision

will strike at the heart of the
old 19th-century institution.

The center of the building
will be stripped back

and reinforced to prepare
for what's to come.

A mega five story,
15,000 ton wedge of glass,

concrete and steel
will cut through the

classic 135-year-old
brick facade.

Inside this awesome extension,
a gallery of new collections

will bring the story
of Dresden up to date.

At its peak,

an 82-foot-high viewing platform
will have breath-taking look out

onto the modern city and point
to Dresden's tragic past.

People can enter
through this new vector

and look at
something so important,

which is where the first bomb
that destroyed Dresden,

where did it land?
Just in front of that wedge.

And the wedge itself
a similar form to the two other

bombs that fell in the back.

So the triangle of bombing,

you're actually standing in it
when you look at the new

horizon of Dresden.

[Narrator] Although
not popular with everyone,

it's the design
the city settles on.

[Narrator] When construction
starts in 2004,

the first challenge is making
sure the 128-year-old building

isn't destroyed by the new
15,000-ton addition.

[Ellie] Adding an extension is
potentially fraught with danger.

Any new load bearing down on the
existing building

could cause it to fracture
and even crack.

It's hard to be sure
how strong the foundations are,

how it was constructed.

It could have experienced
settlement over the decades.

So you have to proceed
with extreme caution.

[Narrator] Delicately,
they slice away 15%

of the original building.

[Daniel]
It's like a brain surgery.

You have to have the scalpel and
all the precision instruments.

You have to know exactly
where you're cutting

and what you're doing.

[Narrator] As well as carefully
removing part of the building,

the engineers need
to strengthen the foundations

where the new structure
will be built.

[Narrator] A network of more
than a hundred slimline

steel reinforced piles is sunk
10 feet under the building

ready for a huge new reinforced
concrete slab to be laid on top.

The delicate, but incredibly
strong foundation system

will support the new extension

without ruining the original
19th-century building.

Now they can turn
their attention

to the extension's
concrete shell

featuring 100-foot-high walls
set at extraordinary angles.

[Narrator] The engineers
use 3D computer modeling

to calculate how thick these
great angled walls need to be.

Then they're built
from reinforced concrete

while huge temporary steel beams
hold the whole thing up.

[Narrator] The heavy new
structure is carefully built

around the old stonework arches.

The building is at its most
vulnerable since 1945.

It's like in a heart transplant
where you hold a patient

on a machine pumping blood
and air to the lungs

while you're changing
the heart of a building.

[Narrator]
That's not the only issue.

The team is struggling to get
a concrete mix that will give

the walls the cast-iron
strength they need.

[Narrator] Finally through
trial and error,

they find the right recipe
for the concrete.

The building goes up
story by story

until finally
the concrete roof goes on.

Now all that's left

is to create the imposing
100-foot steel exterior

with the awe-inspiring
viewing platform

pointing towards Dresden.

It needs to protrude from
the front of the old museum

without destabilizing the
fragile 19th-century facade.

Using a master stroke
of illusion,

the new addition
barely touches the old.

[Narrator] The engineers wait
nervously as the steel arrowhead

is hoisted into position.

[Daniel] I think the most
nerve-wracking day was the day

of seeing the two forms

in complete integrity

speaking to each other.

I think that's really the moment
where you hold your breath.

[Narrator] It's a big success,

as 21st-century steel meets
19th-century brick

and Libeskind's sketch
becomes a living building.

[Narrator] After seven long
years of construction,

the Bundeswehr Military Museum
finally re-opens

to the people of Dresden.

[Narrator] Old is perfectly
intwined with new,

and the added 330,000 square
feet of exhibition space

finally meets Germany's
difficult history head on.

[Daniel] I love that museum.

It's, you know,
so precisely built.

It's so straight-forward,
it speaks to everyone.

I want to make sure
that people understand

what the stakes are for us
human beings in this history.

[music]