Earth's Great Rivers II (2022–…): Season 2, Episode 2 - Danube - full transcript

Earth's great rivers...

..make extraordinary journeys...

..carving through continents,

feeding and connecting life...

..nurturing culture...

..providing a place for adventure.

From the frozen
wilderness of the Yukon...

..to the tropical
heat of the Zambezi...

HIPPO GROANS

..and the magical,
hidden worlds of the Danube.

Great rivers are the lifeblood of
planet Earth.



The majestic Danube...

..almost 2,000 miles long,
from source to sea...

..running through the heart of
Europe.

So much more than a single river.

The Danube is a
giant network of water,

reaching out across the continent.

Flowing east from
Germany and Austria,

all the way to
Romania and the Black Sea.

Its tributaries gather
water from 19 countries...

..making it the most
international river on Earth.

On its journey, it will
cross formidable landscapes

and ancient kingdoms...

..revealing glorious riches

and magical surprises.



But to follow the ever-changing
face of this unique river...

..we start at the very top.

Over 4,000 metres above sea level,

Piz Bernina Mountain in Switzerland

is the highest point of
the entire Danube system.

Here, 800 million tonnes of water

is locked in...as ice.

Four miles long and 250 metres deep,

the Morteratsch glacier,
for most of the year,

is covered in deep snow.

But when temperatures rise in
spring,

and conditions are just right...

..there's a window of opportunity.

Running keeps me alive.

It connects me with nature
and connects me with my own spirit.

Anne-Marie Flammersfeld has
spent most of her life running

the world's toughest landscapes.

Today, she is seizing her moment

to run on the frozen
headwaters of the Danube.

Running on a frozen river,
it's something really weird

because it's only there in
a special period of time.

It looks beautiful,

but looks can be deceiving.

Even in the summertime, running on
a glacier is really dangerous.

You don't know where
the crevasses are.

When you fall into a crevasse, you
can fall for three or five metres.

So it pays to
follow a planned route.

I always try to look for
the best line when I run downhill

because I run downhill really fast,

and I really enjoy it,
and then my eyes are concentrated

on every step and, tak, tak, tak.

And, uh, yeah, this
is most of the fun.

As she nears the
base of the glacier...

..there's a glimpse of the true
power locked up in the ice.

When you look into it
and you see that the water

is coming from somewhere

and you think, "Ah, it's a river."

Beneath the glacier,

the headwaters of the
Danube are on the move.

More than a quarter
of the river's water

comes from the Alps.

And, in spring, it becomes an
unstoppable force of nature...

..fuelling the flow of the
Danube across the continent,

all the way to the Black Sea.

Its journey has only just begun.

A few miles away,

on the slopes of the valley below...

..the melting snow...

..makes way for new beginnings...

..revealing...

..someone's home.

Inside is a creature who
has been waiting to come out...

..for nearly eight months.

A male alpine marmot.

They may seem small,

but, growing up to 8kg,

these are the heavyweights
of the squirrel family.

Winter has not been
easy on him and his kind.

Alpine marmots lose about
a third of their body weight,

stuck in their
burrows during winter.

Now, he needs to fatten up.

The melting snow
has uncovered valuable food.

Marmots eat grasses, flowers,

and even a worm or two...

..if they can find them.

But there's a problem -

other families live here, too.

With only so much food to go around,

he'll need to defend his territory.

And when it comes
to protecting home,

marmots mean business.

An intruder approaches.

It's time to go on the offensive.

To get an advantage...

..marmots rise up and stand tall.

Here in the valley,
it's hand-to-hand combat...

..each pushing and grappling.

Now, keeping your
footing is everything.

But just when the coast seems clear,

there's more danger.

The heat from the sun
now causes giant icicles

to fall from frozen waterfalls.

A blow from one of
these would spell disaster.

Crisis over.

In the valley of the marmots,

life is looking good.

As the meltwaters run on...

..they join countless
other streams and tributaries...

..flowing from all
corners of the Danube system.

Passing through
a myriad of habitats,

some of which hide secret wonders.

In the forests of Bosnia,

one Danube tributary has
a very different source.

These crystal clear waters
are fed by underground springs...

..creating a magical water world.

Legend has it that the Romans were
so stunned by this river's beauty

they named it Una,
meaning "The one."

While the water may look clear,

it's full of dissolved minerals
from the limestone below,

producing a special kind of river

with miniature waterfalls and pools.

As water flows over
moss and other plants,

the dissolved minerals
are gradually absorbed

and collected by
this natural sponge,

which hardens and builds...

..eventually forming
whole new waterfalls.

It's like something
from a fairy tale.

But not everything to see
here is above the water.

Below, there's a party under way.

The nutrient and oxygen-rich
headwaters of the Danube

create the perfect place to
gather and search for food.

Golden shoals of barbel

mix with graceful grayling,
and busy trout.

Many use these
fresh waters to spawn...

..including one species

found nowhere else on Earth.

Each spring, if you look carefully,

you'll find one of the
river's top predators.

The huchen, also known
as the Danube salmon,

can grow over a metre long.

The largest freshwater
salmon in the world.

Today, this pair are
showing their softer side.

With her powerful tail,

the female sweeps away the gravel

to make a small
depression in the riverbed.

A nest in which to lay her eggs.

Very soon, the riverbed looks
like it's had a spring clean.

The male joins her to mate...

..and guards her from
any unwanted attention.

But then...

..perhaps it's best to leave
these giant predators to it.

The secret waters of the
Danube provide a bounty

of opportunity for life.

And where there are fish...

..others will surely follow.

Today, Zdena Gavranovic
is hoping to catch a fish

that thrives in crystal
clear waters,

the trout.

She starts by making
some fishing flies.

IN CROATIAN:

IN ENGLISH: Her aim is to
make the perfect insect...

..something that might just
trick a trout to eat it.

IN CROATIAN:

Tiny feathers for
the wings and silk for the body.

Solid enough to look the part,

yet delicate enough to cast.

Now, time to put them to use.

First, she casts out her line...

..with a loop in the air.

Released on to the water
as light as she can...

..placing the fly to
entice her quarry.

Fly fishing is a
special kind of fishing.

IN CROATIAN:

Timing and rhythm are everything.

Each cast lets out
a little more line...

..a little more hope.

IN CROATIAN:

No luck this time,
not that it matters.

When a river is as
beautiful as this,

that is rewarding enough.

While some are drawn to
the tranquillity of the river,

the waters of the
Danube constantly change.

In Slovenia, one of the
Danube's largest tributaries,

the Sava, offers an
entirely different experience.

Woohoo-hoo!

Like the rushing waters around him,

kayaker Rok Rozman
finds a freedom here.

But it's not without risk.

There might be trees in the rapids,

which can be really dangerous.

There's some rocks
that produce siphons.

So, like old people said,

the river is full of traps.

But, at the same time,
the river is full of joy.

People who meet the river in a kayak

will always see the
river differently.

For Rok, who is also a biologist,

rivers bring so much
more than just enjoyment.

Cos the river has the
most abundance in diversity

and life out of
any habitat, you know?

Transporting nutrients,
water, energy,

it's the most
important part of nature.

And when faced with
the pressures of life,

Rok also believes
the river can help.

If you have problems,

you can go and talk
to the psychiatrist,

or you can go and
sit next to the river.

It's up to you what's nicer,
cheaper, and better.

As they flow down from
headwaters and alpine valleys,

the Danube tributaries
finally come together

to become this great river.

Towns...

..farmland...

..and cities begin
to line its route.

Over thousands of years,
people have settled on its banks

and have tamed the river...

..straightened and engineered

to help protect against annual
flooding.

But there are still
wild places here.

Just outside
Austria's capital, Vienna,

lies Danube-Auen National Park.

A strip of protected
forest and wetland

on the banks of the Danube...

..home to some
extraordinary creatures.

EARTH CRACKLES

A baby European pond turtle.

Buried as an egg four months ago,

it's now hatched and free.

Its mother chose a nesting spot
that would be safe from flooding...

..but now it's far away from water.

And this tiny creature needs
to go on an epic journey...

..all on its own.

But when you're the
size of a thumbnail,

everything is so much larger.

Even tiny ants are a big deal.

But this turtle comes with
its very own suit of armour.

Its arms and legs might be small,

but they are powerful.

Using all its energy,

it instinctively
heads towards water.

Out of all the baby
turtles that hatch every year,

only 2% will make it to adulthood.

And just when you
think you've made it...

..the finish line
seems so very far away.

And it's not just
the turtles on the move.

BELL RINGS

Now or never.

A close shave.

Fortune favours the brave.

Critically endangered in Austria,

every turtle that makes it counts.

At last,

cool and refreshing water.

It might seem unfamiliar
to our young turtle,

but, finally, home.

Safety, food, and even some friends.

Having passed through Germany,
Austria and Slovakia,

the Danube is now at the
midpoint on its great journey

and arrives in Hungary...

..at the majestic
capital of Budapest.

A city that owes its
existence to the Danube

and has seen empires rise and fall,

from the Romans to the Crusaders.

In Budapest, art and
romance intertwine.

Grand architecture,

and no less than seven bridges,

showcase a place that
has been the source

of cultural
inspiration down the ages.

Today, with a
population of 1.7 million,

it is as important as ever.

Water might be one of the
oldest means of transport,

but it's still the cheapest.

And Budapest, because
of its unique location,

is key to the Danube's
continued success

as the backbone of the
European transport network.

Up to 50 million tonnes
of freight are transported

along the Danube each year.

Giant cargo ships and
barges sail from port to port...

..carrying large and heavy loads,

like cereals, sand, and fuel

that would otherwise have to
take less economical routes.

Dockyards act as transport hubs,

where shipping containers and
goods are ferried like clockwork.

A giant, moving jigsaw puzzle,

working 24 hours a day,

seven days a week.

It's easy to see the
importance of the Danube

to everyday life in Budapest,

but there is more.

A secret, hidden from view.

A shaded pool is hard to spot.

But, for two scientists,

it's an ancient wonder
that connects the Danube

to the last Ice Age.

To explore it...

..Dr Gergely Balazs

and Dr Denes Szieberth

need to put on
specialised equipment

as they prepare to enter a cave

that is completely filled...

..with freshwater.

The Molnar Janos caves only started
to be explored in the 1950s,

with the invention of
suitable diving equipment.

We have this busy
city on the top of it.

But the cave,
it's an ancient thing.

Crystal clear water,

filtered through rock
over millennia,

stretches for almost four
miles right under Budapest.

And there's more to be
discovered with each dive.

Some of the passages here are huge,

and the water is so clean
that you don't even see

that you are in the water.

So you are just flying
through these huge spaces.

The caves offer unique
opportunities for the scientists.

You see things
which no-one have seen.

You make measurements which no-one
had the opportunity to make.

This is pure exploration.

Despite the challenges,

the scientists have
already begun to unlock

the secrets of these waters...

..concluding that over a million
litres of water a day

flows imperceptibly
through the caves.

And, in Budapest, there
can only be one destination.

There is an obvious connection.

The cave feeds a lake,

which, through a channel
under the Locash bath,

the water of this lake is
flowing directly into the Danube.

A hidden tributary...

..joining the Danube on its
great journey downstream.

Here, in Hungary,

the Danube's waters may
seem slow and sluggish...

..but they still have the ability

to conjure up moments
of wildlife magic.

On one of its middle tributaries...

..there's an animal that produces

one of the most spectacular
natural events on Earth.

IN HUNGARIAN:

IN ENGLISH: Freshwater
scientist Dr Bela Kiss

is trying to find some of them.

Bela monitors the
population of an insect

that hides underwater
for up to three years.

But, to do that...

..he has to dive down over four
metres to the riverbed.

IN HUNGARIAN:

IN ENGLISH: It might
not look like much...

IN HUNGARIAN:

IN ENGLISH: But in a few months,
these larvae will transform

themselves to become one of
the largest mayflies in the world.

For just a few days in June...

..when the water temperature rises,

they begin to hatch.

First, the males take flight.

IN HUNGARIAN:

IN ENGLISH: For some...

..life is very short indeed.

Soon, more and more
appear from the water.

There's no time to hang around.

They have only three hours to live

and just one purpose...

..to find a female and mate.

The search for newly-hatched females

begins a frenzied mating dance.

The sky soon becomes thick,
with several million mayflies

all mating in groups.

Once common in many
parts of the Danube system,

pollution and habitat-loss

mean this great event
is becoming harder to find.

But if you know where to look...

..it's an astonishing
super-swarm of life.

IN HUNGARIAN:

As quickly as it began,

this remarkable event...

..is over.

After a three-year wait,

it's a short existence,

but it's a life well-lived.

In just one day, they have flown,

mated and died.

By this stage on its journey,

the Danube has been joined
by its major tributaries,

the Drava, the Tisza...

..and the Sava.

Combined, they almost
triple its flow.

As it reaches its third
and final capital city,

Belgrade, in Serbia.

Over half a mile wide,

discharging 5.5 million
litres per second.

This now mighty river...

..flows on towards
the border with Romania

and one of the last great
landmarks on its epic journey.

The Iron Gate gorge.

90 miles long, yet narrowing
to just 150 metres wide.

For thousands of years,

all traffic on the river had
to pass this daunting gateway.

The narrow gorge,
with towering cliffs,

was infamous for its
dangerous rapids and whirlpools...

..making passage in a
boat extremely treacherous.

But in the 1970s,

this part of the
Danube was changed forever...

..when engineers
harnessed the river's power

and created the Iron Gates Dam...

..one of the largest
hydroelectric plants in Europe.

This giant feat of engineering

produces five and a half
million megawatts of electricity,

relied upon by 25 million
people in Romania and Serbia.

A super-structure that has
had an impact on both people...

..and the river.

Below the dam,

the Danube enters the
lowlands of Romania and Bulgaria.

In these waters, there
is one group of animals

that has been deeply affected
by the man-made barrier upstream.

A true monster of the deep...

..the sturgeon.

Some species of sturgeon,
such as the Beluga,

live for over 100 years
and grow up to six metres long,

the size of a shark.

But it's their eggs
that have made them famous,

sold as luxury caviar,

and shipped around the world.

As one of the major rivers
draining into the Black Sea,

the Danube is a vital
spawning ground for sturgeon.

But overfishing, pollution
and the construction of dams,

which have blocked them from
their spawning grounds upstream,

mean this river giant
has all but disappeared.

Now, sturgeon are thought
to be more critically endangered

than any other group of species...

..on the planet.

For one person, their future
is something worth fighting for.

It's my passion.

I want to do it all the time.

Borislava Margaritova,

a fish biologist
working in Bulgaria,

is trying to conserve the health
of the Danube and its fish,

especially four species of extremely
rare sturgeon still found here.

The Danube is the last river

in Europe that they spawn naturally.

So we try to protect them
because they're very rare now.

Today, she's going out with
her team to survey the river.

We are on the river
at five in the morning

and we work most of the
time until the evening time,

ten in the evening.

It depends what we catch.

Using nets, they hope to find
some fish for their research.

But in such a large river,

and with a small team,

it's not going to be easy.

In nine years of doing this work,

Borislava and her team have
only ever caught six sturgeon.

It's very difficult.

You spend eight, nine hours
on the river, on the boat,

and you pick up the nets,
and you see the empty nets.

It's very frustrating for me.

But there is always hope.

And today is a very special
day indeed.

Yes!

HE SHOUTS

THEY CHEER

Incredibly, the team catch not
just one sturgeon, but two.

Smaller than the famous Beluga,
but no less precious.

A young sterlet sturgeon,

estimated to be between
three and five years old.

And a starry sturgeon,

between five and seven years old.

Woo!

It's a huge result for the team.

We try to catch these
specimens for months,

so it's very rare.

We are lucky. Ah-ha!

It's like when
somebody have a birthday

and you have this present
that you want for many,

many years...

HE CHEERS

..and you have it, and it's
not only one, you have both.

They use their precious
time with the fish

to record important data,

including size and weight.

And carefully attach tags,

so they can monitor
the fish's movements.

The significance of this unique
encounter is not lost on Borislava.

The sturgeons are like
a flagship on the Danube.

So, if the sturgeon are still here,

we will know that
the river is healthy.

There is a way to go.

But, for now, Borislava can
celebrate this small victory.

Bye, baby.

It's hoped that
conservation efforts,

like restocking and
protecting migration routes,

might just give these
iconic fish a future.

The Danube has finally arrived

at the last stage
of its epic journey,

saving the greatest
transformation till last.

The Danube Delta.

Passing through Romania and Ukraine,

this mighty river
finally breaks free.

At almost 2,000 square miles,

this is the largest
undisturbed wetland in Europe.

Only fully accessible by boat.

Narrow channels pass through
riverine forests

of willow and poplar.

Opening out into
freshwater marshes...

..fringed with reedbeds...

..and vast lakes
covered in water lilies.

One of Europe's
least inhabited places...

..giving space for
wildlife to thrive.

More than 5,000 animal and
plant species are found here.

The Delta is a globally
important destination for birds,

some migrating from as far away
as Africa and Asia to breed,

like Whiskered Terns
and Squacco Herons.

And one bird that has made
the Danube Delta its own.

The Great White Pelican.

With 17,000 breeding pairs...

..this is the largest
colony in the world

outside of Africa
and their numbers are increasing.

For just a few months,

they'll nest here and
feed on the Delta's bounty...

..working together in giant
flotillas to feast on fish.

A glorious spectacle at the end of
the Danube's great journey,

before, once more, they head
into the Black Sea and beyond.

The Danube's waters have
flowed through more countries

than any river on Earth...

..through a continent
separated by borders

and changed by humanity.

Despite these challenges,

always finding a way to keep
going...

..to inspire...

..to nourish...

..and even astonish.

One continent
connected and united...

..by water.

The Danube and its
tributaries cover 19 countries,

creating the most
international river system on Earth.

To capture its secret hidden worlds,

Earth's Great Rivers
teamed up with local crews,

contributors and
experts right across Europe...

..the people who know the Danube
best.

But it was in Slovenia

that they met
one person who revealed

a different side to
the Danube story...

..a threat that could affect
its future,

as well as many other rivers
around the world.

Biologist and former Olympic rower -

Rok Rozman.

It's this mighty river that
I call home.

The meaning of it is just extremely
big in every way.

Rok has lived all his life on
the Sava river,

one of the Danube's
major tributaries...

..and he knows it as well as anyone.

Sava is really special

because it brings everything
that's stored high up in

the mountains down to
the bottom of the valley.

Without Sava, this valley
wouldn't be green

and we wouldn't have pastures,

and we wouldn't have tourism.

We wouldn't be kayaking,

we wouldn't be fishing,

we wouldn't be enjoying
the sound of the river.

It's basically the essence
of this place.

Woohoo-hoo!

But it isn't just Rok who takes
advantage of the power of rivers.

Over the years,

engineers have harnessed them
across Europe

as a source of energy...

..building dams -

a valuable and low carbon source
of electricity...

..and a way to store water
and help control flooding.

But dams will always create winners
and losers.

And these barriers have
complex implications...

..dramatically reshaping
the river's ecology

up and downstream...

WHISTLE TOOTS

..which is a concern

for many who live alongside
these rivers.

The Sava river already has over
ten dams

and there are plans for ten more.

For Rok,

the damage caused by these barriers
to the wildlife

and ecology of the river
is too great to ignore.

It would be sad to see

such destruction to this river,
you know?

The river provides home
for these animals.

You know,
they can't go anywhere else.

If a bird lives on
a gravel bar, well,

then it lives on a gravel bar.

If an otter needs a river
with fish, well,

then that's what this
river provides,

and that's why it's so important
to protect these rivers.

And by the time we realise

the negative effects,
it's already way too late.

And it just...

..breaks my heart and mind. Erm...

Because if these plans go ahead,

the place where I'm sitting right
now will be underwater.

And it's not just me, I'm the last
in line, you know?

My enjoyment in kayaking is
the last in line.

There's fields here,
people depend on these fields.

There's an otter family
living there.

Where will the birds go?
Where will the plants go?

Free-flowing rivers can be hard
to find in Europe.

Recent research has suggested more
than a million barriers

fragment the continent's rivers.

The Danube and its tributaries

have seen more than 700 dams

and weirs built along their course.

The effect of these man-made
structures

on wildlife is significant.

Faced with this,
Rok decided to do something.

I realised that
emotion without action

is basically going to ruin your
soul eventually,

and I called a bunch of my friends
and I said,

"Look, guys, these rivers are
going to be destroyed without

"anybody knowing if we don't
do something."

CHEERING

We realised that the core of
the problem is that

there's not enough people spending
time next to the river

and we said, "Well,
we're going to take people rafting.

"We're going to take people
picnicking by the river.

"We're going to take them kayaking,
swimming, whatever."

You first need to know a place

to fall in love a place

and only then you're going to feel
the need to protect it.

Rok's initiative has already
helped stop

the building of 12 new dams in
the region.

And one of the dams on his
home river,

the Sava, has now been delayed.

But it's also focused attention on

the importance of allowing rivers
to flow naturally.

Along with lakes and wetlands,

rivers cover less than 1%
of the planet...

..and yet are home to a quarter of
all vertebrate species...

..including over half of all species
of fish.

Hydro is seen as a renewable source.

Their intentions might be good,

but the reality is that what we're
doing is, basically,

we're destroying the most important
parts of our environment.

Hydropower is a major low-carbon
source of electricity,

but as decision makers
are coming to understand

the value of free-flowing rivers...

..its use is being reassessed.

And a revolution
in renewable technologies

may offer exciting alternatives...

..like solar...

..wind, and battery storage,

which could all help keep
rivers flowing.

My hope for the future is that
people realise

the importance of rivers
for themselves...

..then also for all the wildlife
and plants,

and whatever lives next to it...

..because the time is running out.