All language subtitles for secrets.of.ancient.structures.s01e01.480p.web.x264.rmteam

- [Narrator] From ancient
temples to towering cathedrals,

humanity's deepest
beliefs have given rise

to architectural marvels
that defy imagination.

- How on earth is this possible?

- It's the type of building

that inspires movies
and fairytales.

- You would not think
that it was real.

- [Narrator] Faith,
worship, and even fear

have inspired the creation of
unbelievable sacred spaces,

each a testament to
the power of devotion

and human ingenuity.

- It is the largest unreinforced
concrete dome ever built.

- [Narrator] From the enduring
mysteries of the Pantheon.

- How did they raise this
gargantuan structure?

- [Narrator] To the
gravity defying wonder

of Mont-Saint-Michel.

- It looks like it's literally
floating on the water.

- [Narrator] We pull
back the curtain

of how ancient builders
channeled their reverence

into feats of engineering

that continue to
captivate us today.

Pushing the boundaries
of what seemed possible

in their quest to
honor the divine.

- Tales of a divine visit

hint at the reason
the gate survived.

- The Archangel
Michael tells him;

you have to go set up a church
and monastery on this island.

- It's conversion
to Christianity,

and a church is
what has saved it.

(uplifting music)

- [Narrator] At the
heart of modern Rome

stands an engineering triumph.

A building of
unparalleled design.

- You're walking through
these sort of narrow,

typical modern Roman streets,

and all of a sudden,
the Pantheon is just
in front of you.

It just sneaks up on
you. It's amazing.

- Laying eyes on
the Pantheon today

evokes a real sense of wonder.

- It is a stunning
architectural work,

a perfect dome with
an oculus at the top.

- You are left wondering

how on earth they
managed to construct it.

- [Narrator] Nearly
two millennia after
its construction,

the Pantheon remains unrivaled,

the sole structure of its
immense scale and venerable age

to have survived intact
into the modern era.

- It is such an
advanced structure

that it took centuries
for architects

to fully appreciate

and even attempt to
replicate anything like it.

- The Pantheon has the
largest unreinforced dome

in the history of the world.

- What engineering secrets

have enabled the
Pantheon to prevail

while other structures
built at the same time

have fallen into ruin?

- How did they raise
this massive structure?

- Did these ancient Romans
have an advanced knowledge

of math and physics?

- And what inspired
the ancient Romans

to construct the Pantheon
in the first place?

- Pantheon means all the gods.

So you'd think by its name,

it would be a temple
of all the gods.

But it wasn't the
normal thing to do,

so it's a bit of a mystery
exactly what it was.

- In the early
1500s, Michelangelo,

one of the most influential
and talented creators

in Western art history,

lays eyes on the Pantheon's
dome and is awestruck.

He claims it to be angelic
and not of human design.

- [Narrator] Over the
course of history,

many have tried to
emulate the magnificence

of the Pantheon's dome.

- Many modern structures have
been inspired by the Pantheon,

including Saint
Peter's Basilica, the
US Capitol Building,

and the Jefferson Memorial.

- But none have been
able to replicate it

on a scale of grandeur and size

that we see with the Pantheon.

- The sheer scale and complexity

of raising the Pantheon's dome

would have demanded an
extraordinary investment

of resources, labor
and ingenuity.

Who was responsible
for making this happen?

(dramatic music)

- [Narrator] The
bronze inscription

adorning the Pantheon's facade

offers an initial clue

towards unraveling the
mystery of its true architect.

- Across the front
of the Pantheon

is the famous inscription.

In English, it says, Marcus
Agrippa, son of Lucius,

three times consul, made this.

- Marcus Agrippa
was also important.

He was the consul of Rome,

which meant that he oversaw
administrative life,

including the
construction of monuments

which would be dedicated
to Emperor Augustus.

- [Narrator] In 27 BCE,

Octavian Augustus becomes
the first emperor of Rome,

marking the transition
from the Roman Republic

to the Roman Empire.

- Julius Caesar had
been ruled by a Senate.

Now we have his nephew
Augustus, who would succeed him.

His legacy was constructing
this new administrative rule

for the state

in which he, as the ruler,
held supreme authority.

- For Augustus, the
stakes here are immense.

(dramatic music)

- Augustus comes to power
after decades of civil war

and establishes the Pax
Romana, the Peace of Rome.

- [Narrator] His
rule will be defined

by economic
prosperity, stability,

and wide sweeping
infrastructure development.

- Augustus tried to bring
back traditional Roman values,

and one of the ways that
traditional Roman values

were embodied visually was
in the architecture of Rome.

- This was the beating heart

of this massive empire built
on trade and military might.

The structures that were built

would not only serve
the needs of Romans

but would also
manifest his authority.

- [Narrator] At the heart
of Augustus's vision

is the transformation of Rome,

reimagining the ancient capital

as a symbol of imperial
grandeur and efficiency.

- There's a famous
saying which goes,

Augustus found Rome
brick and left it marble.

(dramatic music)

- [Narrator] For centuries,
scholars and visitors alike

accepted the Pantheon's
inscription at face value,

crediting construction of
the Pantheon to Agrippa

during Augustus's reign.

- We put great importance

on inscriptions found
in ancient monuments.

These markings provide
crucial information

about the patronage, dating
and purpose of the structure.

However, when it comes to the
inscription on the Pantheon,

it has done more to confuse.

- [Narrator] This
long held assumption

is challenged
dramatically in 1892

when new archeological
evidence emerges,

revealing a surprising truth.

In April 2020,

a massive sinkhole opens
outside the Pantheon,

exposing a hidden
archeological clue

buried beneath the
city's ancient streets.

- They find ancient
Roman paving stones

that date to the
time of Agrippa.

- These appear to be
the remnants of an
earlier structure,

meaning that the
Pantheon we see today

is actually a reconstruction
built upon the foundations

of an earlier temple.

- [Narrator] Further
archeological evidence

and historical record

reveals that Agrippa's
Pantheon was destroyed

by a fire around 80 CE.

Emperor Domitian rebuilds it,

only to have it
burned down again

in a lightning strike in 110 CE.

The one we see standing today

is completed a decade-and-a-half
later in 125 CE.

- So if this isn't
Agrippa's Pantheon,

then who built the structure

that we see in
front of us today?

- The building, as it stands
now, was built by Hadrian,

a much later emperor.

So why would Hadrian
keep the inscription?

- [Narrator] The
emperor Hadrian,

one of the most significant
leaders of the ancient world,

rules the Roman Empire
from 117 to 138 CE.

He would become known as one
of the Five Good Emperors,

a term that highlights a time

when Rome was led
by capable rulers

who prioritized the
empire's wellbeing

over personal gain or dynasty.

- Hadrian's rule is
characterized by a shift

from expansion to consolidation.

- He was a prolific builder

and his passion for architecture

led to numerous building
projects in Rome

and across the Empire.

- He was someone who
saw building as an
important dimension

of manifesting
imperial power locally.

- By Hadrian giving
credit to Agrippa

for his original construction,

this is a throwback to a very
prosperous and wonderful time

in the Roman Empire..

- It conveys the
idea of continuity,

continuity in the legitimacy
of this imperial rule

from the early Augustan dynasty
now to this new dynasty,

of which Hadrian was a member.

- [Narrator] The
question still remains:

how did the Roman engineers

achieve the seemingly
impossible feat

of constructing and raising
the Pantheon's massive dome?

- Standing in the
middle of the Pantheon

and staring up at the dome
not only hurts your neck

but leaves you speechless,

breathless as to the engineering
and design skills involved.

- Did the Romans
understand the laws

of basic Newtonian physics
long before they were defined?

- Did the ancient
Romans recognize

that the balance

between weight of the
dome itself and its span

are absolutely
inextricably linked?

The lighter the dome, the
further you can span it.

- One of these hints lie in
their unique use of material.

This material not only expands

their engineering capabilities

but helps them create structures

of unprecedented durability.

- The Pantheon is
the living embodiment

of the Urbs Aeterna,
the Eternal City.

And one of the reasons
for its longevity

is a building technique that
was so advanced for its time

that, in many ways,

it far surpasses what we
use today, Roman concrete.

- [Narrator] For centuries,

scholars and engineers
have been captivated

by the extraordinary
durability of Roman concrete

while failing to
uncover its secrets.

- Modern concrete can break
down in as little was 50 years.

But more than a thousand years

after the Western Roman
Empire crumbled to dust,

structures like the
Pantheon are still standing.

How is this possible?

- The poets came to speak
of Rome as the Eternal City

and its architecture was
meant to reflect that.

- Why is it taken us over
2000 years to crack the code

on something that the
Romans used so widely?

- [Narrator]
Researchers had assumed

that the key to the ancient
concrete's durability

lay in one ingredient,

a specific type of
ash that was described

by architects and
historians of that time.

- We're starting to understand

what makes Roman
concrete so special.

So unlike concrete
today, which uses sand,

the Romans used volcanic ash.

And when this volcanic
ash was used as a filler

and mixed with lime,

it made the concrete
incredibly strong.

- [Narrator] But
recent investigations

have unveiled another component
in the ancient Roman formula

that enables it
to repair itself.

- The lime itself produces
a very basic solution,

which leaves calcium
hydroxide in water in pores

in the cement itself.

The volcanic ash material has
a large content of silica.

Silica is sand, so if
you get a crack in it,

what happens is the small
amount of liquid water

which contains calcium
hydroxide moves into that crack,

some of the silicates react
with that calcium hydroxide

to produce more cementitious
material again in the crack

and heal it back up.

So what the Romans actually
created was a concrete

that's essentially self-healing.

- But how did Roman concrete
enable the execution

of the Pantheon's
revolutionary design?

The secret is in the
strategic use of concrete.

- Really what we
want to do in domes

is start out with
a very thick base

and get thinner as we go up,

because the stresses of
the amount of material

that we're actually
supporting above

gets less and less as we go up,

so we can have thinner
and thinner walls.

We actually get a structure

that's easier to
build, is lighter,

and is also more resilient

because it doesn't have as
much mass to start with.

- There are 140 coffers,
which is a recessed square,

in the dome.

They're arranged in
five concentric rows.

The coffers in the dome,

they might have been
strategically placed

to reduce the material, to
lighten that load of that dome.

- [Narrator] Despite these
ingenious strategies,

a fundamental mystery persists.

How did the ancient Romans
raise the colossal dome

to the height at which it stands

considering the rudimentary
technology of their era?

- Do you build that
dome on the ground

and then lift it into place?

Can you lift it up
on a large platform

and then remove the platform?

Do you shore it
up from the ground

and pour the concrete up high?

Do you build those walls
first and put it in place?

There are lots of different ways

that you might approach this.

Which one is the
most successful?

I'd really like to know.

- [Narrator] The
name Pantheon itself

holds cryptic insights.

- What was the true intention

behind this
architectural marvel?

Was it driven by reverence,
obedience, or perhaps fear?

- The word Pantheon
means all the gods.

It's a bit unusual to dedicate
a temple to all the gods,

but the suggestion
clearly is there.

And the structure is there too.

The dome meant to reflect
the dome of the sky.

And so as a temple,

it was a microcosm of the
world, of the universe.

- [Narrator] In ancient Rome,

the line between mortal
emperor and divine deity

was often blurred.

- Romulus was the son
of the war god Mars.

He was the first king of Rome,

and a legend developed that
the site of the Pantheon

was the place where
Romulus is deified

and ascends to heaven.

- [Narrator] But although it
would become popular later on,

at the time when the
original Pantheon was built,

deification of Roman
leaders was not a common

or automatic practice.

- Over time,

we find emperors playing
upon the symbols of divinity.

The idea that emperors are gods

does gradually penetrate Roman
religious culture as well.

- According to one
historical source,

Agrippa wanted to put
a statue of Augustus

with the statues of the other
gods inside the Pantheon,

but Augustus refused,

and so Agrippa put
the statue of Augustus

outside the Pantheon itself
in the portico out front.

But it still associated
Augustus with the gods.

- [Narrator] Hadrian's
reconstructed Pantheon

features a captivating
architectural element

that provides an
alternative perspective

on the building's true
function, the oculus.

- The important part
about the oculus

is that it needs to be located
concentric with the dome,

to ensure that the stresses

that are experienced across
the dome are all equal.

It can't be offset.

It really needs to
be in that center.

Structurally, the oculus
could have been filled in

with concrete material,

but that concrete material would
have to be incredibly thin.

And so maybe there
was constraints

around how thin could
they get that concrete

before it was unable
to be durable enough.

- [Narrator] Beyond the
front doors of the Pantheon,

the nine meter wide opening

stands as the sole
source of light.

More than just
admitting sunlight,

it traces the sun's
journey across the sky.

- One can imagine that
walking into the Pantheon

that you would immediately feel

you were brought into
an otherworldly space,

because the light

that comes through the
oculus during the day

infuses the entire environment

with this very
soft, glowing light.

It evokes a otherworldly space

through this play
of light and dark.

- [Narrator] Recent research
gives further credence

to the suggestion that the
Pantheon was constructed

as a sophisticated
solar calendar,

marking dates of
great significance to
the ancient Romans.

- The study draws parallels

between the temple structure
and Roman-era sundials.

- For the past 2000 years,

if you happen to be in the
Pantheon on April 21st,

the anniversary of
the founding of Rome,

you're going to pay witness
to an incredible spectacle

as light from the oculus
comes streaming down,

focused directly on
the main entrance.

It not only speaks to the
incredible sophistication

of the engineering
to even achieve that,

it also shows how much
cultural importance

the ancient Romans
placed on certain days.

- [Narrator] In the wake
of Christianity's rise,

many magnificent temples and
monuments of ancient Rome

faced a grim fate of
neglect and abandonment.

- After several centuries

of being the center of
spiritual life in Rome,

we find it falling into
a long period of neglect.

In 609, it's Christianized
and turned into a church,

and here again,

it becomes an important
center of worship in Rome.

- [Narrator] The shift
in religious paradigm

threatens to erase

much of the city's
architectural heritage,

leaving many once revered
structures vulnerable

to the ravages of time and
changing cultural values.

- In the centuries
that followed,

much of the old city
of Rome will disappear.

Buildings will be dismantled,
recycled into new buildings.

Others will simply
disappear underground

but not the Pantheon.

The Pantheon, protected by
its new status, will endure.

- What was it about this
particular structure

that allowed it to prevail

when other monuments
of its time did not?

- [Narrator] The
newly restored church

is dedicated as the Church of
Saint Mary and all Martyrs.

- The Pantheon
remains to this day

the largest unreinforced
dome structure in the world.

That itself is a lasting legacy.

Here we are, 2000 years later
and it's still standing.

It is still remarkable.

It's a work of innovation
in and of itself

that hasn't been replicated.

- We're very lucky
to have a building

as unique as the Pantheon.

Regardless of what
your beliefs are,

its conversion to Christianity

and a church is really
what has saved it

and allowed us to
still have access

to such an amazing
architectural wonder today.

(gentle music)

- [Narrator] Off the coast
of France stands a structure

that seems to defy the
very laws of nature.

Reaching skyward in
a daring testament

to humanity's ambitions
to touch the heavens.

Much like the Pantheon,

it embodies our ancestors'
relentless pursuit

of architectural and
engineering ingenuity,

challenging the limits of human
capability and imagination.

(gentle music)

- Mont-Saint-Michel
is a sight to behold.

It looks like something
straight out of a movie.

- This fantastical site

has been compared to
a mythical fortress.

- It's a type of building

that inspires movies
and fairytales.

- It has endured for
over a thousand years,

defying powerful tides,
treacherous quicksand,

harsh weather, and fierce sieges

and still stands proud.

- It looks as much
like a fortress

than it does like a monastery.

- What we see today reflects
over a thousand years

of construction and renovation.

- [Narrator] While
Mont-Saint-Michel

has captivated imaginations
with its legends and mysticism,

the true wonder lies in the
still unanswered questions

surrounding the very real
construction and endurance

of this wonder of the West.

- How did these medieval
builders erect this abbey

on such a narrow pile of rock?

Why the complete rehauling

of the island's
defensive structures,

and how did this incredible
structure end up so isolated

out in the middle of the sea?

- [Narrator]
According to legend,

the island's transformation
into a place of worship

begins with a divine
encounter in the year 708 CE,

when the bishop Aubert
is visited by the
Archangel Michael,

a celestial attendant

associated with
courage and protection.

- According to popular
tradition, in 708,

Bishop Aubert is visited
by the Archangel Michael,

and the Archangel
Michael tells him,

"You have to go set up
a church and monastery

on this island."

And Aubert wakes
up and he thinks,

"Well, that was just a dream,"

and he doesn't do
anything about it.

Three times the
Archangel Michael
supposedly visits Aubert.

- After three visions, he
pokes Aubert in the head,

leaving a hole in his skull.

This is enough to
convince the bishop,

and he resolves to
build the church.

- On October 16th, 709,

Bishop Aubert completes
and consecrates the church,

marking the official
founding of what we now know

as Mont-Saint-Michel.

As the story goes, Aubert
dies just over a decade later,

and his remains are interred

beneath the oratory
he established.

After a millennium of
expansion and change,

in 1792, a man claims to possess
the ancient bishop's skull,

marked with the divine wound

inflicted by the
Archangel Michael.

Today, the skull
is on full display

in the nearby town of Avranches.

But could it actually
belong to Aubert?

While believers
maintain this tale,

some skeptics suggest it may
be the head of someone else,

the prominent hole
showing evidence

of early medical procedures
rather than a holy encounter.

- Stories like Aubert being
visited by the Archangel Michael

are actually incredibly common.

It follows a tradition
of hagiography.

Hagiography are the stories
that are written about saints,

and it's where we get
superheroes of sorts.

They have powers that are
bestowed upon them by God.

A founding of an important
monastery or church

always has much more impact,

if it's associated somehow
with a superpower of sorts,

somehow with a saint, somehow
with an intervention by God.

It makes the site
all the more holy.

- [Narrator] With
no physical remains

of Aubert's original
structure existing today,

does the tale of his hand-built
church hold any truth?

- Does the church really exist?

If it were to be uncovered,

what could it reveal
about the island?

(dramatic music)

- [Narrator] In the 2000s,

the first ever
analysis of bricks

from the chapel
Notre-Dame-Sous-Terre

hopes to reveal fresh insight
into Aubert's original shrine

more than a thousand years
after it was erected.

- The goal is to
date this chapel

to see if it is in
fact the original.

- [Narrator]
Employing a trifecta

of cutting-edge
scientific techniques,

researchers delve into
the secrets of the
ancient structure.

Analyzing approximately
100 bricks,

their results promise
to shed new lights

on the secret past of the
chapel Notre-Dame-Sous-Terre.

- We look at what the
bricks are made of,

and then we can match that
with historical record

to try to marry up what
time period they were made.

- [Narrator] The
results indicate

that the chapel was
constructed in two phases

during the 10th century,

one part in the first half
and one in the second.

- One of the problems when
historians or archeologists

are confronted with a structure

is that it has changed
many times over the years,

and when we're trying to
reconstruct what it was like

at any one period,

we're often left

with a very incomplete
archeological record.

Pieces of old buildings are
reused in new buildings.

That's where we need to turn
to documentary evidence.

And so that's where
historians play a role,

because we'll be going
through the archives

looking for clues

that there was already
Christian monastic activity

happening there.

- [Narrator] A stark contrast
to the humble origins

of Aubert's original church,

the Abbey of
Mont-Saint-Michel towers

approximately 80
meters above sea level.

Atop the Mont summit sits
the transept crossing,

the central point
of the structure

representing the intersection
of Earth and Divinity.

- One of the responsibilities
of the church as a whole

was to make them both love
and fear God at the same time,

and there's no
better way to do that

than with impressive
architecture.

So the whole Gothic
architecture movement

is really a chance
to communicate

to the lowest peasant
and the highest noble

that God lives among us here,

and we all need to
be better Christians.

- [Narrator] Situated at such
a steep elevation, however,

the transept crossing is a
daring architectural gamble.

Not only is this the
symbolic heart of the abbey,

but it is vital

for distributing the weight
of the church structure.

- Adding to the
challenge is the fact

that this was built on
essentially a precipice of rock.

It makes you wonder how did
they get the labor force

to Mont-Saint-Michel?

How did they get their supplies

and materials needed to build
and construct this building?

- [Narrator] With the potential

for catastrophic
failure looming large,

one must ponder what compelling
force or profound belief

would drive the builders

to undertake such a perilous
and ambitious project.

- Pilgrimages happen

because Christians want
to get in close proximity

to the relics of a
holy person, a saint.

- To this day, the
Benedictines in the abbey

claimed to have the
skull of Bishop Aubert.

- Having an important
saint in your monastery

can be a real moneymaker
in the Middle Ages,

because these people are
essentially paying to be there.

And Mont-Saint-Michel was
really the second largest site

of pilgrimage in Europe

for a good period
of the Middle Ages.

- It attracts scholars,
artists, musicians and pilgrims

from across the continent.

- [Narrator] In 1060, Italian
architect William De Volpiano

is chosen to build
the main church

of the new Benedictine abbey.

- So when a monastic
reformer like De Volpiano

is traveling around
the continent and
making these changes,

he's not unusual.

He is part of a larger
trend of what's happening

in the 11th and 12th century.

It's this desire to
standardize monasticism

and make it better,

desire to experiment with
new forms of architecture.

And that's what's happening

when we come to
Mont-Saint-Michel.

We have an effort to join in

in that larger trend that's
happening to better the site.

- [Narrator] Using modern
advanced technologies

like 3D scanning,

scientists are still uncovering
exactly how he did this.

These ongoing studies

reveal labyrinths of
concealed passageways

and previously unknown crypts.

But the key to erecting the
majestic Benedictine church

atop Mont-Saint-Michel
lay in four crucial ones.

- It is built on four crypts,
which is highly unusual,

and these are intended
to serve as foundations

on what is essentially a
very precarious foundation

in this region.

- This is a dauntingly
small rock bed,

only about ten meters in length.

- While this is a really
narrow site to build on,

the best thing about
it is that it's rock.

There are some challenges
with working on rock.

Sometimes the rock might
be quite an uneven surface

and you need to smooth that out.

- We kind of have to flatten
the top of the hill off,

but we don't have the technology

to actually take the
top of the hill off.

So what we do is we
make small, flat areas

by cutting away the granite,

and then we place a portion
of our foundation there,

and then we go up a little
bit and cut another flat spot

into the rock and repeat that.

And then between each
of those flat areas,

we start building
these vaulted arches.

And we keep building
vaulted arches upward

until we flatten the hilltop.

And then we can build our
structure up from there.

- The layout and design of these
crypts is carefully planned

to align with the
structures above them.

- We really need,
with large structures,

the ability to divide the
weight and load of that building

over a large area.

And that's what the
crypts are doing.

Clearly these people
who are designing

and building this structure

recognize the need to move
those loads and divide the loads

over the largest
surface area of the hill

that we possibly can.

- [Narrator] Mont-Saint-Michel's
battle scarred walls

reveal a fortress
fortified by necessity.

- When we look at the
archeological evidence

around the development
of the structure

on Mont-Saint-Michel over time,

it clearly becomes increasingly
more fortress-like.

- During the 13th
and 14th centuries,

the heart of the village
was situated at the top.

But over time, that village

has migrated down to the
bottom of the mountain,

which is where we see it today.

- Mont-Saint-Michel was
itself serving a political

as well as a religious purpose,

so that structure was necessary
to be a place of safety

for those around them.

This was a purpose that we find

with many other
religious institutions
as well at this time.

It's not uncommon
to find a monastery

that looks more like a
fortress in some cases

than it does like a monastery.

(dramatic music)

- [Narrator] Captain
Louis d'Estouteville

stands triumphant atop
Mont-Saint-Michel,

having just
vanquished his enemies

against overwhelming odds.

- In the 15th century,

Mont-Saint-Michel
comes under a siege

that would last decades.

According to legend,

the sands around the fortress

are stained red
with their blood.

This is the Hundred Years' War.

- The Hundred Years'
War is a conflict

that at least gets started

because of a dynastic
dispute in France.

But it's also really about
the territorial ambitions

of both countries.

For the better
part of 100 years,

these two countries will
go to war with one another.

- [Narrator] Due to its
proximity to the border

between Normandy and Brittany,

the stronghold
became a key location

in this century-long conflict.

- During the Hundred Years' War,

it marked an important
stronghold for the French,

one that they maintain
throughout the war,

even when the English were
at their highest point,

when they had routed French
forces in many other locations,

Mont-Saint-Michel
remained impenetrable.

- We do have one reminder
of those efforts,

and that is in two bombard
cannons that they left behind,

which are now affectionately
known as Les Michelettes.

- [Narrator] In
the 19th century,

renowned French writer
and poet Victor Hugo

lays eyes upon
Mont-Saint-Michel.

- Victor Hugo had gone
to Mont-Saint-Michel

hoping for inspiration,

but instead what he found
was utterly shocking.

- [Narrator] Hugo describes
Mont-Saint-Michel:

"Around as far as the eye
can reach, infinite space.

The blue horizon of the sea,
the green horizon of the land.

Clouds, air, liberty,
birds in full flight.

Ships with all sails set.

And then all at once

on the top of an old
wall above our heads,

through a barred window,
a pale face of a prisoner.

I have never felt so strongly
as here the cruel antithesis

which men sometimes
mix with nature."

- This once great
medieval cultural center

had been reduced to a
poorly-kept, brutal prison.

It was something that
affected him profoundly,

and something that
he vowed to change.

- How did this site of
profound spiritual importance

become a place of
confinement and punishment?

- In the late 15th century,

the French King Louis
the XI-th figures out

that actually it's
a great location

to send political prisoners.

- Many of the same
physical characteristics

that made it a functioning

and long living
Benedictine community

also lent itself to
being a prison later on.

First of all, heavily
fortified walls.

It was very difficult to
access, especially at high tide,

and that meant it
was hard to leave.

Internally, it's structured
in terms of cells

that would already have
had built in chambers

in which the monks
would have lived.

So in that sense,

it was an easy way to use
existing institutions.

- Famously, Louis the XI-th
even designed a type of cage

that was put into use
at Mont-Saint-Michel.

It was a metal box
where prisoners would
be locked inside,

and it was soundproof and they'd
be hung from the ceilings.

- This soundproof contraption
cut off the prisoner

from all human contact,

serving as a severe
form of confinement

and psychological torment.

- We're used to experience
the world around us

through our senses.

Now, you put
somebody in this cage

where you can't hear
or sense anything

from the inside of it,

you're cut out from
the world around you.

This is probably as
close as you can get

to simulating this feeling
of no longer being alive,

no longer being
part of the world.

- [Narrator] Adding to
this profound isolation,

Mont-Saint-Michel today boasts
some of the highest tides

in continental Europe.

- You know, at times
it's an island.

At times, it's
surrounded by quicksand.

- [Narrator] But, has
it always been this way?

Ancient texts reveal a legend

that might unlock the secrets

of the tidal island's
geological past.

- The story details that
the Mont's surroundings

were once part of a dense
and expansive forest,

home to a thriving village

that lived in
harmony with nature.

After a great sin is
committed by the villagers,

a tidal wave
destroys the forest,

submerging it beneath the sea.

- The tide came in, washed the
forest and the village away.

And from that point onward,

Mont-Saint-Michel is the
way that we know it now,

surrounded by a turbulent
ocean, alone in its isolation.

- [Narrator] While
the enchanting story

has been passed down
through the ages,

historical and geographical
evidence suggests

it may be more rooted
in folklore than fact,

leaving the true origins of
Mont-Saint-Michel's landscape

shrouded in mystery.

Throughout history, the purpose
and legacy of the structure

is rewritten with each wave
that crashes against its shore.

- Now the monastery
doesn't end then.

It continues,
they're concurrent.

We have the royal prison,

and we have the monastery.

But over time, those
things begin to change.

By the time we get to
the French Revolution,

there's only a handful
of monks there.

The revolutionary government
that comes to power in France

with the French Revolution,
of course, puts an end

to all monasteries in France,

and the prison now takes
on a whole new form.

It's essentially the early
modern equivalent of Alcatraz.

- And by 1863,

some 14,000 prisoners had
passed by Mont-Saint-Michel.

Their very experience would
be utterly discombobulating.

On the one hand,

they're living in
horrid conditions,

suffering torture
and punishment,

yet amid the most beautiful,
awe inspiring surroundings.

- [Narrator] Victor Hugo's
visit to Mont-Saint-Michel

impacts him profoundly.

He is inspired, along with
other notable figures,

to campaign for the
monument's preservation

and end its use as a prison.

In 1874, Mont-Saint-Michel

is converted to a protected site

and designated as a
historical monument in France.

Just as Mont-Saint-Michel
was shaped by devotion,

an ancient sentinel
was preserved by it.

These structures, born of
different eras and purposes,

share a common thread,

the enduring power of human
conviction to shape our world.

Towering above the
German town of Trier

stands an imposing remnant
of the Roman Empire.

- The Porta Nigra

stands as a remarkably
well-preserved testament

to Roman engineering.

It's the largest
surviving Roman city gate

north of the Alps.

Its four-story structure

showcases the architectural
mastery of ancient Rome.

- [Narrator] But for centuries,

details of the gate's past

have remained
cloaked in obscurity.

- When you look at
the Porta Nigra,

it's not like your
prototypical gate.

It's a much more fierce
looking structure,

and it has the nickname
of the Black Gate.

- Porta Nigra is one
of four city gates

surrounding Trier at the time,

and one of many across
the Roman Empire.

So why is it the only
one still standing?

Tales of a divine visit

hint at the real reason
the gate survived.

- There's a story of a monk

that lived within the
walls of the Porta Nigra.

And this is part of the reason

why we think it
still stands today.

But who is this monk and where
does the story come from?

- The Porta Nigra

is a very interesting
example of these Roman gates

that were massive.

They were intended
to be impressive.

- These are vital components
of ancient infrastructure

and urban administration.

- Clearly they were important
in general, of course,

for controlling movement in
and out of cities, for example,

but they use them
in many other ways

that speak to an interest
in memorialization

and also as
expressions of power.

- [Narrator] Unraveling
Porta Nigra's place

in Trier's history

has proven an
intricate challenge

úfor historians to solve.

Trier was founded by the
Romans around 16 BCE,

during the reign of
Emperor Augustus.

The city rose to prominence

when the Roman general
Agrippa constructed a road

from Leon to Cologne in 39 BCE,

enhancing its importance as
a trade and military center.

However, despite
Trier's preservation

of numerous Roman monuments,

more than any other German city,

much of its early history
remains shrouded in mystery.

- At one point it was
turned into a church.

Then, after a period of time,

that part of the
structure was demolished.

Other modifications as well

have sometimes got in the way
of understanding its origins.

- Pinpointing its exact
date of construction

presents a massive challenge.

- [Narrator] In 2017,
researchers unveil new findings

that shed light on the timeline
of this historical landmark.

- This carefully planned dig

aimed to answer the
long standing question

of when exactly the
Porta Nigra was built.

- [Narrator] After
several attempts,

the team comes across
an ancient piece of wood

that will prove key in
unlocking the gate's mysteries.

Using tree ring dating,

they are able to tie the
timber to the year 170 CE.

- It's quite rare to find wood
in the archeological record.

The conditions have to be exact.

Most of the time the soil
has to be not acidic,

more alkaline-rich as
well as waterlogged

because the water keeps
the wood from degrading.

- This discovery is
a huge revelation.

- The city walls of
Trier were constructed

during the reign of
Emperor Marcus Aurelius,

which was a time of relative
peace and prosperity

for the Roman Empire.

- If this is a time
of relative peace,

why build such a
defensive structure?

- [Narrator] The Porta
Nigra was constructed

as part of a system
of four city gates.

- Historical records,
archeological evidence

and the remarkable preservation
of the Porta Nigra itself

help us piece together what
the original gate system

would have looked like.

- [Narrator] The
gate's original design

featured twin four-story towers

flanking a central courtyard.

The courtyard separated the
gate openings on each side,

creating multiple levels of
protection and surveillance.

- So when we think about
rocks and stone masonry,

historically we really couldn't
cut them very accurately.

What makes sandstone
an interesting material

for construction is that
it's really formable.

So even with wooden tools
with stone implements

on their end,

we can actually form
sandstone into complex shapes

and form it very accurately.

Then when we place
those blocks together,

even without mortar,

we end up with a really rigid,
self-supporting structure.

- Interestingly,
despite its grandeur,

the gate appears
to be incomplete.

- Certain sections of
the walls and pillars

appear to be very
roughly finished,

which does not align with the
precision of Roman building.

- Could looming events have
interrupted its construction?

Or was it simply a matter
of budget constraints?

- [Narrator] As a
new millennium dawns,

Trier welcomes an
unexpected visitor,

one who will alter the
spiritual landscape of the city.

- So in 1030, a monk named
Simeon arrives in the city.

He'd been traveling
with an archbishop,

and he pretty much tried
every way to be a monastic.

He'd been a monk in
Egypt, in a monastery.

He'd been a hermit
out in the desert.

None of those things had been
extreme enough for Simeon.

And when he arrives in Trier,

he decides he's going
to take it up a notch.

He's going to be an anchorite.

An anchorite is someone who
essentially dies to the world.

They have themselves
walled up permanently

in some sort of structure

where they can never
leave ever again.

Usually there's a
small space and opening

where food can be
passed to them,

and where waste can be put out.

But that's it. They will
never, ever leave again.

- He has access to great
monasteries and abbeys,

so why would he choose
this old Roman gate?

- Now the whole point
of being an anchorite

is to be seen by other
people being an anchorite.

It's the medieval equivalent
of virtue signaling.

And so the location he chooses

has to be somewhere
with a lot of traffic,

a place where people
are going to notice him

being an anchorite.

So where does he
choose, the Porta Nigra.

- [Narrator] Simeon's request
to be enclosed in Porta Nigra

is granted,

and a ceremony is held

to mark the beginning of the
monk's life as a recluse.

- During the ceremony,

he's enclosed in a cell
high in the gate tower.

- It's irreversible.

Once you've made that choice,

there is no turning back.

You are living your life in
that small, confined space.

- He spends his days
in solitary devotion,

praying and fasting.

- For poor Simeon, it lasted
a total of five years.

Five years. And he died.

And his bones were buried
there in the same cell

where he had ended his days.

- This is part of the
reason why we think

it still stands today,

because he spent time there,
which enabled preservation.

- What motivated these
monks to renounce this life

was both a quest to connect
with God in their current life,

but also to be rewarded
in the afterlife.

- [Narrator] Following
Saint Simeon's death,

the ancient Roman
Gate is expanded

to incorporate a
magnificent medieval church

in the revered monk's honor.

- What we see today

has had its medieval
iterations stripped away,

and it's basically reconstructed
in its original form

to what people would have
seen almost 2000 years ago

when they were
approaching the gate.

- [Narrator] In 1803,

in the aftermath of
the French Revolution,

Napoleon Bonaparte lays
eyes on the Porta Nigra

and becomes intent on
returning the monument

to its former Roman glory.

- It's very interesting
and certainly revealing

that Napoleon, when he came
and saw the Porta Nigra,

his first response was to
destroy the attached church.

Now why would he
want to do that?

That's because he wanted to
evoke the imperial history

of the gate,

and the church was
not part of it.

- Napoleon saw himself connected

to the Roman emperors of old.

And so the Porta Nigra,

rather than it being
a medieval relic,

to Napoleon, it was a symbol
of the great Roman past.

- Napoleon doesn't want
to continue to fight

to build a new legacy

but instead appropriate a
legacy that has already existed.

And in that sense, it's
easier to build on.

It's sort of like momentum;

you start going back far enough

and it's easy to move forward.

But if you're starting from
today, every step is a journey.

- [Narrator] Bonaparte
dismantles the
church and monastery

and today traces of the
gate's religious extensions

are all but eliminated.

- One of the issues
with sandstone

is it's really very porous.

So if you're burning
fires in the Middle Ages

to keep yourself warm,

the smoke is going
to impregnate,

especially the
surfaces of the blocks.

And as we move into
the industrial age,

we now have all of these
industrial pollutants.

Essentially all of that
pollution over many centuries

has absorbed into the
sandstone over time,

and it's turned it from
that natural sandstone color

into being very black.

- Given its imposing appearance,

it does give an allure to it

by being this standalone
black gate that's just there,

waiting to meet visitors.

- [Narrator] A sense
of wonder and mystery

will forever surround these
monumental structures.

The Pantheon's dome whispering
of forgotten deities,

Mont Saint-Michel's
legends and visions

and celestial guidance,

and Porta Nigra's
unfinished stories

echoing through the ages.

These architectural marvels

have revealed
captivating secrets,

yet countless enigmas remain
hidden within their stones.

(dramatic music)

(dramatic music continues)

(dramatic music softens)