All language subtitles for Hidden.Beneath.the.Cities.S01E01.Underground.Cities.and.Secret.Chambers.1080p.DSNP.WEB-DL.DDP5.1.H.264-KHN_track3_[eng]

In Medyat, Turkey,
a research team

uncovers an incredible
discovery.

In the basement
of a historic house,

they found a passageway leading
to several underground chambers.

So far, roughly
100,000 square feet

has been explored.

This complex may be massive
when all of it's been excavated.

In Royston, England,
workmen uncover

an underground chamber.

The most eye-catching
feature has to be

that there are dozens
of images and symbols

cut into the lower part
of the wall.

The question is, who built this
place, and what was it used for?

In Orvieto, Italy,
archaeologists discover

a secret beneath
a private wine cellar.

The team discovered
a striking, rock-cut staircase

descending nearly 33 feet
below street level.

But the site
is just one piece

of a much larger puzzle.

What roles did those
hidden spaces serve?

Below the busy
streets of the world's cities

exists a hidden realm
of wonder.

Sprawling ancient complexes...

mysterious tombs,

top-secret military bases,

strange structures,

and lost artifacts.

Buried beneath our feet
and long forgotten,

until now.

Underground models are exposed

to reveal what lies...

Hidden Beneath the Cities.

Just over 20 miles
from the Syrian border

in the Mardin Province
of southeast Turkey

lies the ancient city
of Midyat.

Midyat spans
over 500 square miles,

and it has a population
of about 120,000 people.

Economically, it's primarily
driven by agriculture,

but it is also the center
of commerce in the region.

And it is a thriving market
where merchants and artisans

sell local goods
and traditional crafts,

such as handmade silver
products and stonework.

The city
attracts up to 3 million

tourists annually,

primarily because of its
historic architecture.

Nine churches and monasteries

are tentative UNESCO
World Heritage Sites.

Over the centuries, Midyat was
occupied by Aramaeans, Persians,

Greeks, Romans, Byzantines,
and Ottomans,

each adding to the work of the
civilization that preceded it.

It's believed
that the city was founded

by the Hurrian people
in the third millennium BCE,

making it around
4,000 years old.

The first recorded
mention of Midyat

was during the time
of King Ashurnasirpal II,

who reigned over
the Neo-Assyrian Empire

from 883 to 859 BCE.

Records refer to a city
called Matiate,

or "City of the Caves,"

and it’s widely assumed that
they were writing about Midyat.

In 2020,
a team associated

with the Mardin Museum
are doing restoration work

in the old town section
of Midyat

when they make
a surprising discovery.

In the basement
of a historic house,

they found a passageway leading
to several underground chambers.

Clearly, they’re not
naturally occurring.

Somebody took the time to
construct these hidden rooms.

Subsequent
excavations reveal

a sophisticated
subterranean complex

of remarkable scope
and sophistication.

They unearthed more
than 50 interconnected rooms

and a tunnel that stretches
almost 400 feet,

as well as a multitude
of artifacts.

So far, roughly 100,000
square feet has been explored,

and it's believed
that this could be

just the tip of the iceberg.

This complex may be massive
when all of it’s been excavated.

The site is given
the name Matiate,

after the old Assyrian name
for the city above it.

So who built this intricate
underground complex, and why?

As the excavations continue,

details of this subterranean
world begin to emerge.

They found holes
thought to be

for housing amphorae,
which are large clay containers

for storing liquid;
in this case, likely wine.

So was this complex constructed

for the production
and storage of wine?

Turkey is one of the oldest
wine-producing regions

in the world, with evidence
of the process

dating back thousands of years.

From around
1700 to 1200 BCE,

the Hittites ruled
much of this region,

and they had a distinct
connection to wine.

Archaeological finds such
as reliefs portraying vines,

grapes and cups, indicate that
wine played an important role

in the Hittite
culture and economy.

So maybe this was also
true of the people

who built the Matiate complex.

Given Midyat's location,

the area was a cultural
and trade crossroads

connecting Mesopotamia
and Anatolia.

So it's certainly possible
that some rooms in the complex

were built to produce wine
and sell it on the open market.

The research team
progresses through

the underground labyrinth
and makes a macabre discovery.

They found human remains!

So was this complex originally
constructed as a burial ground?

Also, they came across
water wells and silos

for food storage, likely grains.

I think this means we can rule
out that the complex was built

as a burial site.

At the risk
of stating the obvious,

the dead don’t need
water or food.

And if it was constructed for
wine production and storage,

there would be no need
for these things either.

People wouldn't have been
down there long enough

to require supplies.

It looks like the
complex was designed for people

to spend extended
periods of time in.

So is it possible that some
of the residents of Midyat

were actually living down here?

Turkey is home
to over 40 underground cities.

The most notable example
is Derinkuyu,

located just over 350 miles
northeast of Midyat

in the Cappadocia region.

Derinkuyu was
discovered in 1963,

when a man doing
renovation work on his home

noticed that his chickens
kept disappearing

through a crack in the rock.

When he investigated,
he discovered a tunnel

which led to
the underground city.

The scale of
Derinkuyu is astounding.

It has 18 levels of tunnels
going down over 250 feet.

The upper levels
were for livestock,

likely to cut down on odors

and potentially hazardous
gas buildups.

Food and wine storage,
residential areas,

and places of worship
make up the lower levels.

There's even a Byzantine-era
school with vaulted ceilings

on the second floor.

There are over 50
ventilation shafts

cut into the rock
to ensure airflow,

and a 180-foot-deep well
provided fresh water.

More than 600 entrances
to the city have been found;

many accessed through
homes on the surface.

And it's believed that
Derinkuyu could have housed

up to 20,000 people
if necessary.

Based on
discovered artifacts,

it's believed that the Hittites
were responsible

for the original construction of
the complex, around 1200 BCE.

And the first mention of the
underground cities in the region

appears in historical records
from roughly 370 BCE.

The prevailing school of thought
is that Derinkuyu,

and other complexes like it,

were used mainly
as temporary dwellings

whenever people were
threatened by outside forces.

Could that be the case
at Matiate?

And if so, who were
they hiding from?

As the investigation
beneath Midyat broadens,

the team uncovers clues

that may just solve the mystery
once and for all.

Roman-era coins
and lamps were found,

and using this information,
we can surmise that the complex

was likely built in
the 2nd or 3rd century CE.

But what's most
telling is that they found

a Christian church and a large
room with a Star of David symbol

on the wall;
probably a Jewish synagogue.

So the picture that emerges
is that the complex

was probably originally
constructed as a refuge

for early Christians and Jews,

and that they may have lived
down here for extended periods.

But why would they need
to go to such lengths?

In the early
first century CE,

the Roman Empire didn't
make a distinction

between Christians and Jews,

because the first followers
of Christianity

were largely Jewish.

But in 64 CE,
a fire devastated Rome,

and Emperor Nero attributed it
to the Christians.

Religious persecution
began in earnest.

By the 2nd century CE,
Christians were viewed

as criminals, but persecution
was not widespread;

it was localized and sporadic.

Then in the year 250,
Emperor Decius decreed

that Christians were a threat
to the Roman order

and should be treated as such,

with all the power and brutality
that the empire could muster.

While the exact numbers
are impossible to know,

it’s thought that thousands
of Christians were executed.

But in 313,
Emperor Constantine issued

the Edict of Milan,
making Christianity legal.

And then in 380,
Emperor Theodosius issued

the Edict of Thessalonica,
declaring Nicene Christianity

the official religion
of the Roman Empire.

However, evidence
suggests that the people

of Midyat continued to use
the underground complex

to hide from
later civilizations,

such as the Persians.

And there are even medieval
accounts of invading armies

encountering deserted cities,

suggesting prolonged use of the
region’s subterranean hideout.

The research team
believes that the Metiate site

was repeatedly repurposed
over the centuries,

above and beyond
its original function

as a refuge from
religious persecution.

Given the evidence,
when the space wasn't occupied,

it must have served
various purposes

for the people living
in the city above.

A storage space
for wine and food,

and considering the presence
of human remains,

a catacomb for the dead,

and maybe even a simple respite
from the blistering summer heat.

It's thought that
Matiate was continually expanded

and reshaped over the centuries

by the people
who lived in the city,

resulting in this
extraordinary complex.

Amazingly, we think that
less than 5% of it

has been uncovered.

So when all is said and done,

it may prove to be the largest
underground city in the world.

Some experts
speculate that Matiate

may span a staggering
4 million square feet

and was capable of housing
up to 70,000 people.

But for now,
that's only speculation,

and the truth remains hidden
beneath the city of Midyat.

Just under 50 miles
north of London, England,

in the county of Hertfordshire,
lies the town of Royston.

Almost 2,000 years ago,

the Romans built
this north-south road

that connected what is now York
and what is now London,

and this became one of the most
vital thoroughfares in England.

Royston developed where
that north-south road

bisects another road,
one that ran west to east

from the Salisbury Plain
to East Anglia.

In 1162 CE,
a chapel was built at Royston

and dedicated to
St. John the Baptist.

This was later expanded
into an Augustinian priory,

which is a small
Roman Catholic monastery

devoted to the teachings
of St. Augustine,

a North African bishop,
theologian, and philosopher.

Following that,
a market was founded,

and the town grew around it.

King James I stopped
in Royston in 1603

when he was on his way
from Edinburgh to London

for his coronation.

He was smitten with the area
and he eventually built

a hunting retreat in the town,

which became one of his
favorite residences.

Part of that lodge still exists,

and many of Royston's
other buildings

also reflect the town’s
long, rich history.

August 1742,
workmen are building a bench

in Royston's Mercat House,
a cheese and butter market,

when they uncover a surprise.

They were digging
a post hole

and struck a millstone
buried in the ground.

And when that millstone
was lifted out,

they found this vertical shaft
about two feet in diameter.

And the best part is
there were toe holds carved

into either side of the shaft
that would work as steps.

A small boy was
recruited to go down first,

followed by a man skinny enough
to fit through the opening.

They discovered that the opening
led to another cavity

which was filled
with dirt and debris.

Perhaps thinking that they had
found buried treasure,

a team was assembled
to empty the space,

and some 200 loads of dirt
were ultimately removed,

revealing an incredible chamber.

It's bell-shaped
and extends roughly 25 feet

from floor to ceiling.

Its diameter is around 17 feet,

and it’s hollowed out
of chalky sedimentary rock.

A number of recesses are
carved into the walls.

Some oblong, others kind
of shaped like ovens.

But the most eye-catching
feature has to be

that there are dozens
of images and symbols

cut into the lower part
of the walls.

The question is, who built this
place and what was it used for?

The initial
investigation of the space

reveals several items
of interest.

According to records,

they found fragments
of a small drinking cup,

a piece of brass
with no markings,

and most interestingly,
decayed bones and a human skull.

So maybe what we’re looking at
is an elaborate gravesite.

Among the iconography
carved into the walls,

there are a bunch
of religious references.

So you can see why people might
have thought this cave

was a religious site
and a possible burial site.

Due to the cave's
shape and location,

other ideas about the site’s
origins come to light.

Some theorize that the
cave may have been what's called

a denehole, essentially
an ancient chalk mine.

Chalk was extracted
for two main purposes,

farming and building materials,
because when burned,

chalk could produce quicklime,

which was used in fertilizer,
in bricks, and in mortar.

If you compare Royston
Cave to other denehole sites

in southern England,
the layout is similar.

You've got this
slender vertical shaft

leading down to one or several
bell-shaped cavities.

Also, like at Royston,
a lot of mines were established

near crossroads, possibly
because chalk was used

to build and maintain the roads.

And here’s the third piece.

After use, those shafts were
often blocked with objects

or backfill, which is exactly
what we see at Royston.

But the backfill in
the Royston cave must have been

added after the imagery
was etched into the walls.

It had to be removed
to reveal the carvings.

So it's possible that the site
was originally a chalk mine,

but was repurposed later
for a different use

and then blocked off unfilled.

In the 1990s,

some 250 years after
the cave's discovery,

a local devises
a theory of his own,

connecting the site to
an ancient secret society.

He proposed that the
cave was an early ritual site

of the Freemasons,

which is the world's oldest
fraternal organization

and is known for its use
of secret symbols,

signs, and ceremonies.

Now, its exact
origins are murky,

but Freemasonry is
believed to have evolved

from the early guilds
of stonemasons

who built Britain’s cathedrals
and castles in the Middle Ages.

Eventually, lodges were created

where people could exchange
ideas about the trade,

but as time went on,
some people began accepting

honorary members,

and that led to the development
of Freemasonry.

It's believed that
Freemasonry originated

in Scotland where
King James I was from.

We know he had a residence
in Royston

and spent a lot of time there,
which has led to speculation

that the cave may have been
a private place for the king

to engage in Freemasonry rituals

hidden away from any nosy
members of the royal court.

A deeper look
into the cave's

enigmatic iconography may prove
to support this theory.

One of the images
on the wall shows a figure

holding a candle in one hand
and a skull in the other.

The skull could
represent mortality,

and the candle might
represent knowledge,

so this could be a reference
to a man being initiated

into the Freemasons

and experiencing
a symbolic metamorphosis.

There's also a carving
of Saint Lawrence,

a historical figure known
for his faith and courage,

and there happens to be a degree
named after him in Freemasonry.

A degree is like a step up
the ladder of advancement,

representing a stage
of personal development

and increased knowledge
within the fraternity.

Below St. Lawrence,
there's an image believed to be

King David of the Psalms.

One of his arms bends
to form a perfect square,

a cornerstone
of Masonic imagery,

usually accompanied by a compass

and symbolizing morality
and honesty.

And by the main
crucifixion scene,

there are also carvings of hands
with hearts in them,

which represent charity
in today’s Freemasonry.

Here's the thing,
there are lots of connections

between the iconography
we see in the cave

and imagery associated
with Freemasons.

But the thing is, the Freemasons
are super secretive.

So it's not really clear whether
the symbols we associate

with them today had been adapted
in the time of King James' reign

in the early 1600s.

But if this theory is true, the
Royston Cave would be the oldest

Freemasonic ritual site
in all of England.

Thing is though, there are
no historical records

that verify King James was even
a member of the Freemasons.

Unsatisfied with
any of the explanations

surrounding the cave's purpose,

an archaeologist conducts
an extensive study of records

relating to the site,

and in 1978 proposes
a theory of her own.

She believed that
the cave was originally used

as a storage site
for the Knights Templar,

and that it was repurposed into
a private worship space for them

after disagreements
with Royston’s priory.

The Knights Templar
were a Catholic military order

founded in the 12th century

to protect Christian pilgrims
traveling to the Holy Land.

They were known for
their fighting abilities

and involvement in the Crusades,

but also for acquiring large
amounts of wealth and land

throughout Europe,
including Hertfordshire,

where Royston Cave is located.

Just eight miles away,
the Templars had a stronghold

in Baldock, and they would
visit Royston

to sell produce at the market.

And there are records
of squabbles

between them and
the priory’s monks over fees.

And in 1254,
the master of the Templars

sued the head of the monastery
for detaining and beating

some of his men who had come to
conduct business at the market.

The Templars were
obligated to pray every day,

and if they had fallen out
with any priory's monks,

they likely sought out
another place to worship.

The Royston Cave may have
provided this space for them,

and considering the ample
amount of religious imagery,

this theory makes sense
on some levels.

Inside the cave,
a closer look

at the intricate etchings
on the walls

provides the strongest evidence

of a connection
to the Knights Templar.

Some of the carvings,
those depicting hands,

axe heads, hearts,
and concentric circles,

can also be found on the walls
of Tour du Coudray

in the Castle of Chinon
in France.

This castle was used
as a prison,

where some prominent members of
the Knights Templar were held

after they were arrested
in October 1307,

including their last
Grand Master, Jacques de Molay.

This is hardly
the kind of connection

that can be shrugged off
as coincidence.

And the Knight's Templar theory
is the most captivating

explanation of
the Royston Cave’s purpose.

But still, no official record
or concrete proof

of its age or function
has ever been found.

In the 1790s,
an entrepreneurial resident

of a neighboring house
dug a tunnel into the cave

and began charging admission,

which is how it is
still accessed.

Thousands of people flock to
the Royston Cave every year

to marvel at one of England's
greatest mysteries,

buried under the streets
of this ancient town.

Around 60 miles
north of Rome,

in Umbria, central Italy,

the town of Orvieto rises 640
feet above the valleys below,

perched on an isolated volcanic
rock at the meeting point

of the Paglia
and Chiana rivers.

The earliest occupation

of the Orvieto Plateau
dates to the Villanovan Period,

around 1100 to 750 BCE.

Its strategic position
above the Paglia Valley

and near the Tiber River

fostered agriculture, trade,
and regional exchange.

Artisans produced fine pottery
and bronze works,

with trade networks reaching
across the Mediterranean.

By the 8th century BCE,
the settlement had developed

into Velsna, which is one
of the most important cities

in the Etruscan world.

The Etruscan civilization itself
covered a bunch

of what is now central Italy
during the Iron Age,

including modern Tuscany,
Lazio and Umbria,

and it expanded into
neighboring regions over time.

At its height,
Velsna, today called Orvieto,

was fortified by
a four-mile wall system,

underscoring its power and the
rivalries among Etruscan cities.

Inscriptions show its influence
extended northward,

but rising tensions with Rome
led to conflict, and in 264 BCE,

a final siege resulted in
its destruction by Roman forces.

In May 2012,
archaeologists begin excavating

a private wine cellar
on Via Ripa Medici,

on the west side of Orvieto,
near the ancient Porta Romana.

What they uncover marks
the start of a new chapter

in a search to understand
the city’s layered history.

Beneath the cellar slab,

the team discovered
a striking rock-cut staircase

carved into the west wall,

descending nearly 33 feet
below street level

before opening into a chamber.

The space, labeled Area A,
widens as it descends,

forming a truncated pyramid

roughly 20 by 23 feet
at its base.

Beyond Area A,
the site includes

ancient and medieval cisterns,
tunnels and niches,

revealing a continuous
evolving use over centuries.

Perhaps most intriguing is
a second pyramidal chamber,

labeled Area B.

Although left for
future excavation,

Area B is already known
to connect with Area A

via an Etruscan tunnel,
which is now filled

with a gray, sandy,
pozzolana-like material.

This is a volcanic ash,
or burnt earth,

that when mixed
with lime and water

can be used for
mortar or cement.

But the site,
now called Cavità 254,

is just one piece of
a much larger puzzle.

Since the late 1970s,
more than 1,200 human-made

subterranean structures have
been documented beneath Orvieto.

Wells, cisterns,
tunnels, chambers, and more

all accumulated over the course
of nearly 3,000 years.

Together, these spaces
form a hidden city,

suggesting a complex
relationship

between Orvieto's surface life

and the secret world
beneath its streets.

So, what roles did those
hidden spaces serve?

The carved walls and
stepped cuts inside Cavità 254

may reveal a deeper story,

one rooted in the city’s drive
to build grand monuments above.

As excavations
progressed,

it was noted that the stone
stairs turned at a right angle

along the north wall
before terminating.

In antiquity, these stairs
collapsed and were replaced

by a wooden beam system
pegged into post holes.

Could these carefully engineered
access systems,

along with chisel marks,
indicate that Cavità 254

was designed as a controlled
quarry to extract tufa?

A soft porous rock,

which was crucial in Orvieto’s
monumental architecture.

Material dumped
into Cavità 254

includes large quantities
of gray bucchero,

a shiny, dark gray to black
pottery made by the Etruscans

from the 7th to the 4th
century BCE,

along with black and red figure
pottery, common ware fragments,

and wash basins
and building tiles.

In several cases, fragments
from the same vessel were found

in different locations,
indicating rapid infill,

rather than slow accumulation.

This could point to on-site
quarry debris left in place

when the quarrying
abruptly ended.

About 50 miles south,
in Cerveteri,

the site of the Etruscan
city of Cisra,

the Vigna Parocchiale area
offers valuable parallels

that may illuminate
Cavità 254's possible function

as a controlled quarry.

Observatory excavations in 1983

uncovered this huge trench

that seems to originally
have been dug as a quarry.

After quarrying
at Cerveteri,

the trench was abruptly filled
in the early 5th century BCE

with about 21,000
cubic feet of debris.

This wasn’t a gradual
sort of landfill.

It was dumped rapidly
in one coordinated act,

using materials from nearby
prestigious buildings

like architectural terracottas,

column bases, and
fine decorative pieces.

In Cavità 254,
we see the same abrupt infill,

massive volumes of pottery
and architectural fragments,

all dating no later
than roughly 430 BCE.

These parallels could suggest
a shared practice

of sealing exhausted quarries

with symbolic
or practical debris.

But the well-finished walls,

except for the eastern one,

don’t align with material
extraction practices.

Instead of rough surfaces
for efficient block removal,

these dressed walls point
to a different intention.

And also, the presence
of the spiral staircase

is highly unusual
in quarry design,

hinting at a more complex use.

Among Orvieto's
underground spaces,

certain clues have led some
to wonder if Cavità 254

served a more carefully
engineered function,

woven into the city life above.

Maybe Cavità 254
played a role

in the management
of Orvieto’s water supply.

Living on a high plateau
is all fine and dandy

from a military perspective,
but water doesn’t flow uphill.

The Etruscans would have
had to come up

with some serious
hydraulic ingenuity,

and maybe that's what this is.

Question is, though, could
Cavità 254 have been part

of a larger drainage
or stabilization system

hidden beneath the city?

Many settlements were
built on high tufa plateaus

in central Italy,
where the water table

lay too deep to reach easily.

To survive, communities
relied on collecting

and storing rainwater,

using carefully designed
underground systems

instead of tapping groundwater.

Across southern
Etruria, bottle-shaped cisterns,

typically cylindrical
with a narrow neck,

became essential features

between the 7th
and 3rd centuries BCE.

Many included pure clay rings
for waterproofing,

a detail specifically noted

in Orvieto’s so-called
Type I cisterns.

These forms demonstrate
a well-established tradition

of adapting subterranean spaces

for secure water collection
and storage.

In Orvieto itself,
other cisterns

connected to rock-cut basins

created sophisticated
storage networks

designed to retain
surface runoff

and stabilize supply
above the deeper aquifer.

This layered hydraulic strategy
highlights just how deeply

water management shaped the
urban fabric of Etruscan cities.

But Cavità 254 lacks
the defining features

of true cistern systems.

There are no catchment channels,
draw shafts, or overflow drains.

Besides, its lack of
waterproofing rules out

any original use
as a water reservoir.

So altogether, these clues
suggest the space

served an evolving function.

Some look to the
complete sealing of Cavità 254

as an enduring intentional act.

The upper layers
of Cavità 254 were reshaped

in later centuries,
including a cellar floor.

Just below, archaeologists found
a dome-shaped deposit

of mixed Etruscan materials,

likely poured from
an original top opening,

and a thick pozzolana ash layer
about three feet deep,

intentionally sealing
the Etruscan fills.

So could this final,
deliberate closure

represent an ultimate act
of ritual burial?

Among 188 inscribed
pieces of ceramic at that site,

most are marked
with a single letter

or a short sequence of letters
or symbolic signs.

Those inscriptions almost
always run right to left,

and they show these deliberate
standardized markings.

This is not random.

One of the most
striking finds

is a small terracotta relief,

depicting a kneeling
male warrior,

vividly painted and detailed.

The disheveled facial features,
ungrained eyes,

and half-open mouth
evoke the astonishment

of Capaneus from
the Pyrgi Pediment,

a rare Etruscan relief
from the Temple of Pyrgi

that illustrates hubris
and its consequences.

This reinforces the idea
that objects deposited here

carry deep symbolic weight.

While selective
pottery-rich fills do appear

at other Etruscan sites,
no direct parallel

to Cavità 254's deliberate
multi-layered ceiling

has been identified.

What final message or purpose
this act or this space

was meant to serve
ultimately remains unclear.

Beneath the streets
of Orvieto lies a hidden world

carved from tufa, preserving
traces of ancient labor,

ritual, and intention, but
defying any single explanation.

Cavità 254 reflects this wider
underground mystery,

with 1,200 cavities
still guarding secrets

we’re only beginning
to uncover.

About 90 miles southwest
of Yazd city,

in central Iran's
Golden Triangle

stands Abarkuh,
a Silk Road outpost

that linked Persian trade
for more than 1,500 years.

Abarkuh is part
of Yazd Province

in Iran’s central plateau.

This vast arid expanse is ringed
by the Zagros Mountains,

the Alborz Range, and
the eastern Iranian highlands.

Historically, settlements formed
along the plateau’s edges.

Thriving in pockets were rivers
descending from the highlands,

replenished groundwater, and
allowed agriculture to flourish.

Among the oldest
of these settlements,

Abarkuh was shaped by relentless
drought, extreme scarcity,

and blisteringly hot summers,

often surpassing
100 degrees Fahrenheit.

Its endurance depended entirely

on careful stewardship
of limited resources.

And over the generations,

residents developed
a sophisticated system

of earthen architecture,

water management,
and spatial planning.

And this allowed them to
transform this harsh landscape

into a sustainable city.

During
routine inspections

of five historic homes
in Abarkuh's old quarter,

surveyors detect something
unexpected beneath the ground.

The homes had been
built atop rocky foundations,

and the spaces between
those rocky areas

had been turned into gardens.

Using aerial photos and
archaeological studies,

they determined there were
small stone chambers

carved beneath the homes.

After 18 months
of excavation,

they uncovered a vast
subterranean network

of corridors, pathways,
and chambers.

In some areas, the tunnels
were just three feet high,

while others reached
nearly 10 feet.

So far, roughly
650,000 square feet

of the underground labyrinth
has been documented.

But estimates suggest
that roughly 150 acres,

about one third of
Abarkuh's historic core,

can seal subterranean
corridors and chambers.

The scale and the state
of preservation here

raise deeper questions.

Why build such an extensive
network beneath the city?

And what purpose did
these tunnels serve?

Abarkuh's tunnel
network's scale and precision

hint at an urgent purpose,

possibly shaped by
the pressures of its time.

The meticulous
stonework aligns precisely

with known Qajar dynasty-era
constructions above ground.

Historical records confirm
the Qajars' extensive investment

in subterranean
infrastructures--

reservoirs, cisterns,
and tunnel networks--

indicating there's a possibility

that Abarkuh’s tunnels were
established during this era.

The Qajars,
originally a Turkmen tribe

from present-day Azerbaijan,

rose to prominence
amid intense conflict.

After 1779, Agha Mohammed Khan
launched a ruthless campaign

to unify Iran, ultimately
founding the Qajar dynasty

sometime between 1785 and 1789,

a dynasty that endured
until 1925.

This period was defined
by violence and upheaval,

with entire cities
facing destruction.

In such chaotic times,
communities like Abarkuh

may have naturally sought
safety underground,

away from open conflict.

But so far,
we just don't know if there were

any clear defensive or
fortification features

such as gates,
caches of weapons,

or fortifications in Abarkuh.

Instead, the tunnels appear
designed for broader utility.

They may have offered safety
during a crisis,

but security likely
wasn't their sole

or even their primary purpose.

As the investigation
progresses,

archaeologists notice
patterns in the layout;

spaces within the tunnels
that suggest

deliberate and
multifunctional design.

The deeper, cooler
chambers may have provided

seasonal relief during
the harshest months,

offering residents comfortable
areas to gather and rest.

Some might have stayed
underground for extended periods

as surface conditions
became too extreme.

Similar approaches
to subterranean living

appear globally.

On China's lowest plateau,

communities have inhabited
cave dwellings

for thousands of years,

showcasing parallel innovations
in underground architecture.

Dikengyuan,
or sunken courtyard homes,

offered insulation from severe
winters and scorching summers.

Each courtyard was
accessed by ramps,

seamlessly integrating
underground spaces

with surface life.

Similarly, Abarkuh's
tunnels feature stairs

descending directly into
the underground network.

Larger chambers
contain carved niches

and deliberate access points,

clearly designed
for practical daily use.

Over 3,000 miles
to the west

in the Mediterranean region,

underground spaces also
safeguarded vital resources,

particularly food supplies.

In the 15th century,

Valencia became
a major trading power,

which prompted the construction
of extensive subterranean silos.

By 1573, the city built silos

covering roughly
66,000 square feet,

all built beneath a major square
measuring only 240 by 230 feet.

In 2015, a study used GPS
and GPR to determine

there were a total of 48 silos

and hidden
subterranean granaries.

These silos,
embedded in clay-rich soil

on an elevated hilltop,

maintained consistent cool
temperatures and low humidity,

essential for long-term
grain storage.

Abarkuh, however,
shows no signs of food storage

or permanent occupation.

Its layout suggests it may have
had evolving purposes,

like temporary refuge,
seasonal usage,

and perhaps
eventual abandonment.

Still, the scale and precision
of the network

prompt deeper questions
about its full intent.

Historically,
subterranean construction

reflects an ancient tradition
of engineering

adapted to environmental
challenges.

The city of Matera
in southern Italy

is a remarkable example
of this ingenuity.

Starting in the 9th century,

Matera's residents carved
elaborate homes and cisterns

directly into limestone bedrock.

This created a sophisticated
and self-sufficient

underground ecosystem.

With no rivers nearby,
the city relied on capturing

spring water and rain
through an extensive network

of cisterns and
filtration systems.

Limestone gutters and clay
channels guided water runoff

into homes, transforming Matera

into a highly effective
water harvesting community.

Like Matera,
Abarkuh conceals

a meticulously engineered
subterranean world.

And it's located in an area
with limited access

to fresh water inside the city.

So could the complex beneath
the city have been constructed

to supply its citizens
with much needed water?

Based on
the evidence at hand

and historical engineering
projects in the region,

the researchers reach
a consensus on the origins

of Abarkuh’s
subterranean complex.

The network was likely
built as an aqueduct,

a part of Persia's
ancient qanat tradition

that has supported
water infrastructure

across the region
for thousands of years.

These sophisticated hand-dug
systems of gently sloped shafts

and tunnels were designed to tap
groundwater beneath hillsides.

Gravity would carry it
for miles, sometimes up to 30,

to sustain drinking, farming,
and long-term survival

through extended dry seasons.

In Iran, a network
of around 22,000 qanat systems

stretching over 155,000 miles

was fully operational
until recently,

with major cities like Tehran
relying on them

well into the 1960s and '70s.

In Yazd alone, the qanat system
still delivers

about 12 billion cubic feet
of water each year.

That's roughly a quarter of the
province's groundwater needs,

despite only receiving around
2.5 inches of rain annually.

Because it was built
on rocky terrain,

Abarkuh faced difficulty
distributing surface water

to farmland downstream.

Engineers circumvented this
by excavating

extensive underground corridors,
channeling vital water supplies

through solid rock directly
to agricultural areas.

Traditional qanats
often featured reservoirs,

water mills, and rest stations,

details that closely resemble
Abarkuh’s niches and chambers.

Some families built staircases
connecting their homes

directly to the tunnels,

enabling easy water access
and management,

and a naturally cool
environment.

Over generations, the tunnels
likely evolved and expanded

into larger spaces, suited
to various communal needs.

After some of
the aqueducts dried up,

sewage systems were rerouted
into the old channels,

making full excavation
impossible

and obscuring whatever else
might be down there.

We know roughly when
the complex was built

and how it may have been used;

but how far it reached,

how long it operated,
and why it disappeared,

all of that remains a mystery.

Beneath Abarkuh lies
an enduring record

of ingenuity and adaptation,

capturing how
communities survived

through resourcefulness.

But even now, only fragments
have come to light.

The rest remains
buried in stone,

waiting to be understood.