Original subtitles

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.