NARRATOR: In the heart of Germany
stands one of the most iconic sites on the continent...
...Heidelberg.
A castle, once glorious beyond compare, now in ruins.
(Birds squawk)
NARRATOR: As Europe emerged from the dark ages,
the most brilliant light of learning
emanated from this city.
The vibrant river and mountains teemed with wild creatures.
Animals beckoned to scientists and physicians
as subjects for study and inspiration.
But new ideas about religion
soon pitted Protestant against Catholic,
sparking a war that would tear Europe asunder,
and reduce the great castle to rubble.
Amidst human tragedy,
the animals managed to adapt and even thrive,
writing a new chapter in the history of Heidelberg.
(♪♪♪)
NARRATOR: Heidelberg Castle was once among
the most majestic sights in Europe.
The sunny slopes of the surrounding Odenwald Mountains
provided unsurpassed natural bounty.
At the foot of the castle,
the River Neckar linked Heidelberg
to the mighty Rhine and to the world.
Powerful rulers here served the Holy Roman Empire.
They turned Heidelberg into the foremost center
of learning in Europe.
In every direction, nature's living laboratory
offered up a wealth of plants and animals to be studied.
A new era of science blossomed in a most unexpected place...
...the Church of the Holy Spirit,
just a stone's throw from the castle
in the heart of old-town Heidelberg.
Today the church watches over a different kind of new beginning.
Peregrine falcons had nearly disappeared
by the end of the 20th century, victims of pesticide exposure.
But the birds are making a comeback,
and they've found an ideal breeding place...
...in the church bell tower.
(Birds chirp)
NARRATOR: Three new chicks have just emerged.
Their parents take turns gently sitting on them
to keep them warm.
(Birds chirp)
NARRATOR: It will be 42 days
until they're big enough to leave the nest.
Until then, the parents will provide
a steady stream of pigeons and doves,
and round-the-clock care.
(Birds chirp)
(Bells ring)
NARRATOR: Beneath the bell tower nursery lies the birthplace
of the very first university in Germany,
now more than 600 years old.
Founded in 1386,
the young school soon became
a center of philosophy and medicine.
The church coffers provided funding,
and its halls offered space for research.
After centuries of the Dark Ages,
the light of science and medicine
at last shined in Heidelberg.
(Birds chirp)
NARRATOR: Like those early academics,
the young peregrines have plenty to discover
in the surrounding landscape.
Rich hunting grounds are right on their doorstep,
just beyond the castle ruins.
As the male leaves in search of food,
he heads southeast to the foothills
of the Odenwald Mountains.
Odenwald means "forest of legends."
Today it's a 1,000 square mile
nature preserve, the perfect place
for a legendary hunter to return.
Beneath the canopy are many of the same plants and animals
that were here 600 years ago.
Heidelberg's early physicians sought them out,
walking this forest to find ingredients
for their concoctions and cures.
This male European toad has just emerged
from a state of suspended animation.
It spent the winter buried underground, as still as death.
Then, when nighttime temperatures rose
to around 40 degrees Fahrenheit
and a rejuvenating rain soaked the earth,
thousands emerged en masse.
(Water splashes)
His singular mission is to get to the breeding pond,
the same one he was born in.
To get there, he'll cover almost
half a mile a day.
The going gets tough, but he can't afford to be late.
En route, the male keeps a lookout for a female.
If he finds one, he'll hop on board
and let her carry him the rest of the way.
(Toads croak)
NARRATOR: She's bigger, but in addition to carrying him
she's hauling thousands of unfertilized eggs
in her abdomen.
Finally, their goal is in sight...
...not a woodland pond, but Heidelberg Castle.
The castle's spring-fed fountains
are one of the most important amphibian spawning grounds
in the region.
This may look like traditional mating,
but actual fertilization happens in the water.
She lays a string of eggs,
and from his prime position on her back,
he fertilizes them as they emerge.
They'll swim together for up to 12 hours
stringing yards of fertilized eggs
among the aquatic plants and branches.
A jelly-like substance forms a protective cover
around the eggs as they develop.
These grass frog eggs operate on the same principle,
only they're arranged in a cluster instead of a string,
providing a little more protection.
The outermost eggs remain vulnerable,
and a little alpine newt has decided
that one would make a very nice meal.
Fortunately, there are a few thousand left.
These days, the frogs and toads can get on with mating here,
unmolested by humans.
In the 15th century, they didn't have it so good.
(Footsteps move nearer)
NARRATOR: Amphibians like them were raw materials for medicine
that was supposed to impart
their animal abilities to humans.
Their moist, permeable skin was the charm.
Salamanders were boiled alive
to make lotions for treating burns.
Frogs were cooked in sesame oil to cure arthritis and gout.
Such ideas might seem ludicrous today,
but many modern drugs
are derived from chemicals in frogs' skin.
A line can be drawn from modern pharmacology
directly back to these first laboratory kitchens.
(♪♪♪)
While knowledge grew, the old power of mythology
and symbolism still influenced science.
(♪♪♪)
For inspiration, physicians turned to Asclepius,
the Greek god of medicine.
Wrapped on his staff
is one of the most enduring animal totems in medicine...
...the snake.
The ability to shed its skin
was to scientists of the day nothing short of rejuvenation,
the ultimate healing power.
Heidelberg's local serpent is a rarity.
In Germany, the Aesculapian snake only exists
in three isolated areas,
one being the Odenwald Mountains.
At almost six feet long,
it's the longest snake in this country.
It keeps its head up while cruising
to see its surroundings
and pick up scents with its forked tongue.
(Snake rattles)
NARRATOR: Mice and other small mammals are its favorite food,
but it won't turn up its nose at lizards or amphibians.
It's also an excellent climber, so even birds aren't safe.
(Birds chirp)
NARRATOR: When it finds prey, the snake kills by constriction,
as it lacks the venom
that has fascinated scientists for centuries.
Fortunately, modern science no longer condemns snakes
to the apothecary's pot.
But their appearance as a symbol
of the medical profession endures.
As the 16th century dawned,
science at Heidelberg had already progressed
by leaps and bounds.
The Book of Medicine, written here,
was the most comprehensive work
of medical science in its time.
Its thirteen volumes contain over 18,000 remedies
and medicinal plants,
many of which are still acknowledged today.
Its creator was none other than Heidelberg's Louis V,
who ruled the city during the early 16th century.
It took him more than 20 years to write these books by hand.
When he wasn't writing,
Louis V was busy overseeing
a massive expansion project.
He enlarged the castle's library
to fit the ever-growing number of books.
More construction followed.
Details of this architecture point to his love of nature.
Like the physicians, Heidelberg's architects looked
to the surrounding natural world for inspiration.
They didn't have to look far.
Right below the castle flows the Neckar River.
It's home to an animal that inspires all builders...
...the beaver.
Like Louis V and his forebears,
this family of beavers has built its stately home
over many generations.
Last year's offspring are almost as big their parents.
These kits will continue to live in the family keep
for around two years, before striking out on their own
to become the architects of a brand new wetland.
Since beavers spend much of their lives in the water,
it's critical that they're well waterproofed.
They spend hours grooming and oiling their fur.
Glands between their back legs
secrete an oily substance called castoreum,
which they meticulously comb through their fur.
This substance made beavers
a target of Heidelberg's burgeoning medical science.
Physicians extracted the castoreum from these glands
to use as a remedy for everything
from ulcers to fevers, to cramps and rheumatism.
The secret to its healing properties
lies in the beaver's diet.
Willow bark contains salicylic acid,
the raw ingredient of aspirin.
The waterproofing castoreum
contains high levels of this compound.
For the beavers, though, willow branches are just food.
They can grow to up to 66 pounds
eating little else.
Their teeth are specially designed for the job,
coated in a hard layer of red iron oxide.
As a beaver's teeth grind over each other,
they sharpen to a blade.
Wood that's too tough to eat becomes building material.
Beavers use the water to transport big willow boughs.
It's much easier and safer
to float and swim than to drag them over land.
Moving goods up and down the river
was key to the growth of Heidelberg as well.
14 miles downstream,
the River Neckar flows into the Rhine,
one of Europe's most important trade routes.
Spices and exotic plants from all over the world
made their way upriver to the city.
On the opposite bank from the castle,
non-native plants found a surprisingly favorable climate.
The southern exposure of the Odenwald Mountains
makes this one of the warmest regions of Germany.
Mediterranean plants that are seldom found
north of The Alps thrive here.
Almond, peach and apricot trees,
even pomegranates bear fruit here.
(♪♪♪)
(Birds chirp)
NARRATOR: Terraced orchards divided by stone walls
make the most of the sunshine.
Warm-weather creatures take advantage as well.
Sand lizards and more common wall lizards
dwell in the many cracks and crevices.
As cold-blooded reptiles,
they can't internally regulate their body temperature,
so they have to live somewhere
with both warming sunshine and cooling shade.
Their scaly skin keeps them from losing moisture.
But as this sand lizard grows, he needs to replace his jacket.
This sloughing of skin happens many times a year.
To ease the itch and help the process along,
the lizards make good use of the rough stone walls.
The stones are also a great place
to soak up the morning sun after a chilly night.
Once the lizards have warmed up their muscles,
they can head out to hunt.
Cocking their heads, they scan the surroundings.
With so many flowering trees,
insects are never in short supply.
It's all a matter of being quicker than the bug.
There are always surprises.
An ant puts up a valiant fight over this grasshopper.
A risky move against a hungry sand lizard,
but it makes off with a morsel to bring back to the nest.
(Bee buzzes)
NARRATOR: Among the many flowering trees, one bug reigns...
...honeybees are crucial pollinators.
(Bees buzz)
NARRATOR: A new colony is setting up a nest
in one of the terrace walls.
With their queen protected,
they get to work building a nursery of honeycomb.
They glue their structure together with propolis,
a mixture of plant oils, sap and wax fermented with bee saliva.
It has the added benefit
of protecting the surface of the nest from bacteria and fungi.
In the field of pharmacology,
Heidelberg's bees were way ahead of its human scientists.
Nursery ready, the queen begins to lay her eggs,
depositing one into each cell.
Now it's up to the youngest bees to care for the larvae,
all of which are female.
After 21 days,
they welcome their new sister bees into the hive.
The sunny south-facing bank of Heidelberg
doesn't just appeal to plants and animals.
Students from the university once came here
to stroll and ponder life's questions.
Today the place is still known as the Philosopher's Way.
Nature was a place for reflection and contemplation.
The place for serious research was back across the river.
The Church of the Holy Spirit
had been the birthplace of the great university.
Now it assumed a new role
as the biggest library of the Renaissance in Germany.
The vast galleries were filled with books that represented
the best available knowledge on all subjects.
The brightly-lit rooms were perfect for reading.
One of the most cherished manuscripts
was "The Art of Falconry,"
written by the Holy Roman Emperor
Kaiser Frederick himself in 1248.
It's considered the first work of zoology
written in the spirit of modern science.
In Heidelberg's golden age, people raided falcon nests
for chicks to hand-rear for sport.
(Bird squawks)
NARRATOR: Today, the three chicks living in the church bell tower
have no such problems.
They can take in the best view of the city
while waiting for their mother to return with food.
Six weeks have passed since they hatched.
Their fluffy down has given way to proper feathers for flight.
Instinct tells them to flap, but these two chicks
don't have the confidence for take off just yet.
Their brave sibling, though,
has already made it to a nearby rooftop,
just in time to miss the food delivery at the nest.
The others are waiting eagerly
as their mother returns with a pigeon.
But there's no reward for being timid.
She pulls the meal back to the window.
If they want to eat,
they'll have to step out of their comfort zone
and take a leap of faith.
(♪♪♪)
The brave chick tries to catch up with its mother.
But landing on the steep tower
is a tough maneuver for a first outing.
(♪♪♪)
NARRATOR: It's a big day for the young falcons,
as they change from nest-bound chicks to fully-fledged adults.
In the early 1600s,
a fledgling prince struggled
with the sudden ascent to power.
Frederick V was only 14 years old
when he assumed the rule of Heidelberg.
The young Prince found himself on the cusp of history.
The Protestant Reformation
had been gaining influence in Germany
and Heidelberg had become a Protestant city,
ruled now by a Protestant prince.
Tensions with the Catholic Church in Rome were on the rise.
But the young ruler's reign was also in danger
on another front closer to home.
By the age of 18, he began to suffer from strange fevers.
Heidelberg's best doctors claimed that foul odors
from swamps along the River Neckar were to blame.
They weren't too far off.
It wasn't the swamp air, but the mosquitoes that bred there.
Today we think of malaria as a tropical disease.
But in the early 17th Century,
mosquitos carrying the malaria parasite
existed well into the temperate zone.
The mosquitoes still persist in Heidelberg's wetlands today,
but they no longer carry the disease.
Tiny rafts of mosquito eggs float on the stagnant surface
of one of the Neckar's small tributaries.
The islands are only the size of a grain of rice
but hold between 200 and 300 eggs.
Underneath, the larvae have already begun to hatch.
They continually filter-feed
microscopic plankton from the water.
They breathe through their tails,
which poke like snorkels through the surface film.
They'll shed their skin three times as larvae,
growing larger each time.
On the fourth shed, they become pupa,
with recognizable wings and eyes.
From the pupa, they emerge as adult mosquitos
to break the water's surface.
It would take doctors almost three more centuries
to trace malaria to mosquitoes.
Prince Frederick's doctors held to the belief
that foul air was to blame.
The word "malaria" literally means "bad air."
And the best way to combat bad air
was with pleasant smelling fragrances.
The doctors of Heidelberg gathered bundles of flowers
from the Odenwald Mountains to treat the ailing prince.
They dried the flowers and infused them in oil
to concentrate their fragrance.
Today the practice is known as aromatherapy.
The blossoms may have eased young Frederick's fever,
but he remained sickly and weak.
When he wasn't suffering, he sought solace in nature
and a blossoming love for his young wife Elizabeth Stuart,
the English King's daughter.
To honor her, he built the Elizabeth Gate.
This declaration of love
is covered in images of tiny natural wonders.
To complement the gate,
he commissioned a French engineer
to lay out a sumptuous garden.
At the time of its creation,
many considered it the eighth wonder of the world.
It was to be the embodiment of creation itself,
a veritable Garden of Eden.
He planted such a variety of flowers
that there would be blooms every month of the year.
He built balconies to overlook the splendor,
secret grottos, and elaborate spring-fed fountains.
The very fountains that today are a haven for amphibians.
These alpine newts are having their annual spring mixer.
The males are spruced up for the occasion.
Their normally drab skin has turned bright and iridescent.
The females keep their usual brownish-grey attire,
but their bellies swell with unfertilized eggs.
The male's dragon-like crest is enlarged,
as is his cloaca,
the reproductive opening at the base of his tail.
(♪♪♪)
Competition is fierce.
Not all will find a mate.
The sense of smell plays a big role in courtship.
Although newts breathe air,
an organ in their mouths can detect smells underwater.
That way he can tell if she's ready for wooing.
The time is right, so he vibrates his tail
to show he's ready, and that seals the deal for her.
Many other creatures rely on the fountains for reproduction.
Fire Salamanders have already mated,
but the females need these pools
to give birth to their live larvae.
There's an unexpected problem.
Amorous male toads fresh in from the forest
are looking for mates.
They'll latch on to anything that moves.
The salamander mother is undeterred.
One by one, her babies emerge in their protective sacs.
As each one drifts to the bottom, the sac bursts
and a fully developed larva emerges.
After a moment to recover from the ordeal,
it's ready to swim and feed.
For now, it breathes through feathery gills.
Most other amphibians begin as fertilized eggs.
Being born as a group offers some protection.
The toad tadpoles also have gills.
The cold, oxygen-rich water is perfect in this larval phase.
But the transformation to terrestrial animals
has already begun.
Each species proceeds in its own particular way.
The toads' gills retract and become internal;
meanwhile, they're developing lungs.
Grass frog tadpoles are already growing hind legs.
(♪♪♪)
NARRATOR: Alpine newts still have external gills,
but they already have all four legs.
Such rapid development requires a lot of fuel.
A veritable banquet of water fleas,
worms, and insect larvae does the trick.
New fire salamanders are just as voracious.
They're already getting their adult spots.
Each pattern is unique, like a fingerprint.
Every species follows a different schedule,
but the moment of transformation eventually arrives for all.
Young toads break their watery confines and step onto land.
Tadpoles no more, they look almost identical
to their parents...
...only a lot smaller!
When you're that tiny, everything is an obstacle.
But soon the tables will turn.
(♪♪♪)
(Toad croaks)
NARRATOR: In 17th-century Heidelberg,
a big transformation was also underway.
A storm was brewing over Europe,
the likes of which no one had seen.
The Holy Roman Empire was determined
to enforce Catholicism in all its territories.
Heidelberg stood in direct opposition.
The ideas that fueled the Reformation
flowed from its Protestant chapel.
Frederick V, the young, sickly prince,
pledged to defend the Protestant faith.
Under pressure from his allies, Frederick traveled to Prague
to be crowned the Protestant king.
His reign would be so brief
that history now calls him "The Winter King."
The Catholic League answered this provocation
with full military might.
In 1620, Frederick's forces met the Catholic army
on the banks of the Vltava River
in what is now the Czech Republic.
(Gunshots)
(♪♪♪)
NARRATOR: The Protestant troops were annihilated,
and Frederick fled into exile.
Still, the Catholic forces were not satisfied.
They wanted to root out the Reformation at its core.
So they took aim at Heidelberg itself.
Fear spread through the city.
People saw omens in the natural world.
(Birds squawk)
NARRATOR: Common swifts, seeming to appear out of nowhere,
like a vast winged army,
were believed to predict bad things to come.
Their unsettling cry earned them the name "screech devils."
But these spring migrants
were merely harbingers of fair weather.
Swifts live their lives in the air.
They can stay in the skies for months without landing.
They do almost everything on the wing.
But they have to land to nest and raise young.
Every year, they make the journey
from the Sahara Desert to Germany.
They're drawn to rocky cliffs and, since it's destruction,
to the old battlements of Heidelberg.
A hole in an old turret is the perfect spot.
The castle walls are well occupied.
While the swifts have the turret
and the falcons are in the belfry,
a family of common kestrels has claimed an arrow slit.
The parents patrol constantly,
scoping for enemies or prey.
Kestrels hover in mid-air to scan the ground below.
Their sharp eyes can detect the faintest movement in the grass.
Thanks to their parents' hunting skills,
the chicks don't have to wait long to be fed.
In the castle tower next door,
the five-week-old swift chicks have grown their adult feathers.
Only their white faces betray them as youngsters.
In just another week,
they'll be making their first trek to Africa,
not coming to rest until they have chicks of their own.
No other bird spends as much of its life on the wing.
Adult swifts that haven't managed to breed this year
aren't caught sitting still.
In the evenings, they organize into huge groups
called "screaming parties."
Together they climb to heights
of between 6,000 to 9,000 feet.
They'll spend the entire night circling high above the castle.
They can even sleep on the wing
by shutting down half their brain at a time.
On mild summer nights,
hundreds of pipistrelle bats
swarm through the battlements.
It's thought that the adults are showing their offspring
the best places for hibernation when winter comes
in a few months' time.
Ounce-for-ounce, the common pipistrelle
is one of the world's smallest mammals,
weighing little more than a sugar cube.
When its wings are folded, it's smaller than a matchbox.
(Bats call)
NARRATOR: The pipistrelles share the castle walls
with larger mouse-eared bats.
Up to a thousand congregate here.
They spent winter tucked deep into the battlements,
slowing their metabolism and living off of fat stores.
Now that it's warm, they're active,
nabbing as many bugs as they can while the pickings are good.
Whatever the season, the castle walls provide
all the protection the bats need.
The same could not be said
for the 17th-century citizens of Heidelberg.
Frederick V had put his effort into lavish gardens
at the expense of strong fortifications.
In July 1622, the Catholic army crossed the River Neckar.
For 11 weeks, they laid siege to Heidelberg.
(Footsteps)
NARRATOR: On the 19th of September, 1622, the city fell.
(Gunshots)
NARRATOR: The Catholic army
razed Heidelberg Castle and city to the ground.
The exiled Frederick V never returned home.
The ensuing Thirty Years' War
between Protestants and Catholics
tore Europe apart.
Entire regions lay in waste.
Plague and starvation took an even greater toll.
But few places suffered more than Heidelberg.
Frederick's magnificent gardens,
once considered the eighth wonder of the world,
lay in ruin.
The precious library,
one of the greatest seats of learning
Europe had ever known, was dismantled.
The victorious Catholics sawed church pews
into chests for transport
and shipped the university's treasured collection of books
to Rome as a gift to the Pope.
For many years, the castle remained uninhabited.
In Heidelberg, the Reformation was over.
The city was Catholic once more.
The young peregrine falcons
are undergoing a conversion of their own.
They've left their home in the Protestant Church
of the Holy Spirit and have come to rest
on the nearby Jesuit Church.
From here, they make daily trips into the forest
for intensive training.
As the world's fastest birds,
they'll soon be dive bombing their prey
at up to 240 miles per hour.
But they have to learn how to harness all that speed.
Mother tempts her offspring with a piece of food.
All three youngsters join in the game of keep-away.
(♪♪♪)
NARRATOR: It's all in service of perfecting
the high-speed maneuvers that will keep them,
and their future families, well fed.
(♪♪♪)
NARRATOR: One day, mother and father won't show up with food.
The young falcons will be on their own.
40 years after the fall of Heidelberg,
a precocious youngster was also stepping out into the world.
A young girl named Liselotte, granddaughter of Frederick V,
brought a ray of hope to the beleaguered city.
She was a boisterous child who loved to play in nature.
In the spirit of Heidelberg's past,
she was a budding scientist,
who is said to have kept snakes in her room.
But the times were against the curious Liselotte.
In the mid 17th century,
the field of science was off limits to women.
Instead, Liselotte was married
into the court of Louis XIV of France.
Her family hoped that the marriage
would inspire the powerful Catholic Sun King
to protect their homeland.
They were wrong.
In 1688, French troops invaded and once again destroyed
the city of Heidelberg.
Citizens were burned alive in churches
and the city was razed yet again.
Liselotte could do nothing to stop the carnage
and blamed herself.
She wrote,
"All night, as soon as I fall asleep a little,"
"I see all the destruction."
"And then I drift and cannot sleep again."
"I lament that I am the downfall of my fatherland."
NARRATOR: In the years that followed, the once great city
fell into a fairy-tale sleep among the ruins.
But in the rubble of lost glory, animals found a haven.
(Bird squawks)
The castle that could not protect its people
now succeeds in protecting its wildlife.
Almost by accident, Heidelberg has again become
a living laboratory of natural science.
In its own way,
living up to its promise from centuries ago.
(♪♪♪)