All language subtitles for Hidden.Beneath.the.Cities.S01E04.Tunnels.and.Tombs.1080p.DSNP.WEB-DL.DDP5.1.H.264-KHN_track3_[eng]

In Ybor City, Florida,

workers uncover hidden tunnels,

raising questions
surrounding their purpose.

Who had the means,

who had the motive
to build them?

And what might they suggest
about the hidden activity

that once moved
beneath Ybor City?

In Naples, Italy,

a hidden tomb is uncovered
deep underground.

We believe
the necropolis once held

dozens of tombs.

But key questions persist.

Who was buried here?

And what do these elaborate
chambers tell us

about the Hellenistic Neapolis?

In Nushabad, Iran,
a local digging a well

unearths a massive underground
complex known today as Ouyi.

Ouyi had
largely stayed hidden

from the modern world
until its rediscovery in 2006.

And the question remains, why
was it built in the first place?

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 marvels are exposed
to reveal what lies

Hidden Beneath the Cities.

Three miles northeast
of downtown Tampa, Florida,

lies Ybor City, a vibrant
neighborhood born of industry

and shaped by immigrants.

But long ago, it was a haven
for organized crime

where ambition
and vice collided.

In 1885,
Spanish-born magnate

Vicente Martínez Ybor
moved his operations

from Key West to Tampa,
pushed by labor unrest,

weak infrastructure, and
political instability in Cuba.

Attracted by Tampa's
rail lines and port,

he bought 40 acres
northeast of downtown

and built a planned community
of factories and worker housing,

laying the foundation
for the city's rise

as an industrial powerhouse.

In 1896,
cigar industrialists

expanded their reach by founding
the Florida Brewing Company.

Set near key rail lines
and Government Spring,

a crucial water source,
the brewery thrived.

By 1900, it was reportedly
exporting more beer to Cuba

than any other American brewery.

As Ybor City expanded,

so did Tampa's underworld.

From the late 1800s through
the mid-20th century,

the city gained a reputation
for organized crime

that was so entrenched that
federal authorities ranked it

as one of America's
most corrupt cities.

In November 2018,
demolition crews

working at 12th Street
and 6th Avenue in Ybor City

uncover a brick-lined tunnel,
reigniting questions

about the neighborhood's
rumored subterranean past.

The tunnel has
rounded ceilings

and a flat, mostly dirt floor,

and modifications like
intersecting pipes,

electrical wiring,
and double locks.

Reinforced by three
layers of brick,

the ceiling sits roughly
one foot beneath street level.

While a small
segment of the tunnel

was initially exposed during
streetcar construction

in the early 2000s,

the 2018 excavation revealed
additional details:

glass bottles,
traces of a spring,

and a direct connection
into the basement

of the Florida Brewing Company.

At least three tunnels

have been documented
beneath Ybor.

At the former Blue Ribbon Store
on 7th Avenue and 15th Street,

a local news report mentioned
three separate passages

extending from
the 26,000-square-foot building.

A fire in 2000
destroyed the building

and sealed any
existing entrances,

leaving the extent
of these tunnels unknown.

In a region where
basements are uncommon,

these tunnels raise
important questions.

Who had the means, who had
the motive to build them?

And what might they suggest
about the hidden activity

that once moved
beneath Ybor City?

The straightforward
design of the tunnels suggests

they might have initially
served a practical purpose.

The tunnel
discovered in 2018

appears to date to between
1885 and the late 1890s,

right in line with Ybor City's
early expansion.

Structurally, it matches
dual-use sewer systems

designed to manage both
wastewater and stormwater

that were constructed in other
US cities around that time.

Could the tunnels represent
the city's first attempts

at sanitation and
stormwater control?

In the 1700 and 1800s,

cities along
the Eastern Seaboard

built brick storm drains that
doubled as sewage channels.

Gravity would transport waste
toward the bays or channels.

The tunnel discovered in 2018
likely once extended

directly to the Ybor Channel
before being sealed off,

which supports the idea that
it originally functioned

to carry wastewater
toward the waterfront.

At the time, Tampa was
experiencing explosive growth.

The arrival of the railroad
in 1883,

the construction of the
ultra-luxurious Tampa Bay Hotel

in 1891, and the rise
of the cigar manufacturing

and brewing industries
transformed the city.

By 1900, Tampa's population
had tripled to 16,000.

Dealing with sewage and drainage

would have likely
been a concern.

Roughly 1,000 miles
north, in New York City,

similar challenges led
to groundbreaking

infrastructure innovations.

By 1849, New York's
population had surged

to nearly 500,000 people.

Sewage flowed into the rivers,
and the city was struck

by one of its worst
outbreaks of cholera.

In response, 70 miles
of sewer pipe were laid

in just five years.

It's reasonable to think that
other fast-growing cities

like Ybor may have looked
to similar solutions.

In Ybor, a team
laser-scanning the 2018 tunnel

found an artesian spring still
flowing through the tunnel,

one that was documented
nearly a century earlier.

While the spring alone doesn't
confirm the tunnel's purpose,

its presence along with
the drainage pipes

strongly suggests
the structure was intended

for early water management
or sewage.

Interestingly,
some of the pipes

date to the 1970s or '80s,

indicating later reuse
or modification.

While this particular tunnel
was eventually identified

as a stormwater sewer
on a 1927 city plan,

other tunnels don't appear
in official records.

Some of the tunnels
also have flat dirt floors,

which make them less effective
for drainage.

While they may have started
as part of Ybor's

early sanitation efforts,

more advanced systems
were in place by 1905.

So it's possible
their use evolved

beyond any original
civic function.

Local lore,
combined with the location

of the tunnels,
has led some to question

whether they were built or
later used for covert activity.

Even before
national prohibition,

Florida had enacted
its own ban on alcohol,

which meant that Tampa was dry.

But by the 1920s,

liquor arrived by boat
from Cuba and the Caribbean,

and it also came in
from local stills

across Hillsborough County.

Given the hundreds of
bootlegging arrests on record,

could these tunnels
have offered smugglers

a protected route
underneath Ybor?

By 1930,
Tampa had roughly

130 underground
liquor retailers.

In Ybor, bootlegging became
a thriving cottage industry.

Some estimates suggest half
the neighborhood's families

were involved, as homemade
stills supplied cafes,

restaurants, and speakeasies.

With that level of activity,
the tunnels may have offered

a discreet way to move
cash and contraband,

especially for Tampa's
Italian community

who profited heavily
from the trade.

That underworld
economy overlapped

with the rise of mob figures
like Charlie Wall

who built an empire on gambling,

and by the 1890s had taken over
Tampa's Bolita Rackets,

an illegal numbers game
with an 80-to-1 payoff,

reportedly with backing
from local business leaders

eager to keep profits
in the city.

By the 1930s,
Italian bootlegging operations

were encroaching
on Wall's territory.

A violent turf war broke out,
and in the late '30s,

assassins tried to kill
Charlie Wall in broad daylight,

blasting at his car
with a sawed-off shotgun.

But Wall escaped into his home,

slipping through
a tunnel-like passage

that linked his garage
to the house.

In that climate, tunnels would
have offered a secure way

to transport contraband

and an essential means
of escape and protection.

Just 20 miles
southwest in St. Petersburg,

another tunnel offers
a possible glimpse

into how criminal networks
in Florida

may have operated below ground.

Beneath the historic
Snell Arcade,

a reinforced concrete tunnel

extends roughly 30 feet
under the sidewalk.

It's only accessible through

a hidden four-square-foot hatch
in the basement,

and Al Capone was rumored
to have kept an office there.

During Prohibition,
the Snell Arcade housed

a rooftop nightclub
rumored to be a speakeasy,

and a taxi office linked
to several moonshine arrests

in the 1930s.

Given that history,
the tunnel may have offered

a way to move alcohol
without drawing attention

from the police or the public.

While the Snell Arcade
tunnel might have

initially served
as utility access,

some suggest it continues
beyond the basement wall,

possibly extending beneath the
street toward a former bank.

This alignment has led some
to believe that the tunnel

was later adapted for
secretly transporting cash

or other contraband.

But here's the thing,

there's been no reported
conclusive evidence

linking Ybor's tunnels
to organized crime.

In the 1920s, public corruption
and limited policing--

at times just nine officers
for the entire city--

meant organized crime related
to Bolita and Prohibition

could operate without relying
on elaborate tunnel systems.

But that doesn't mean
they didn't serve

another nefarious purpose.

Historians are now
confident that Ybor's tunnels

originated as part of
an early sewage system

abandoned by the city
before the 1920s.

And while the passageways have
never been definitively tied

to running contraband,

it's not a stretch to wonder
if bootleggers and smugglers

used these secret corridors
for their illicit purposes.

The tunnels beneath
Ybor City offer traces

of a complex past
and could illustrate a town

defined as much by what
was hidden below ground

as by what built above it.

On the western coast
of the Italian peninsula,

120 miles southeast of Rome,

Naples sits on
the sweeping curve

of the bay that bears its name.

Naples sits within
a natural arc of hills

that stretches from
the promontory of Posillipo

to the Sorrentine peninsula.

This coastal setting helped
define its long role

as a maritime hub,
first in Greek antiquity,

and later as one
of the Mediterranean's

most influential port cities.

Greek colonists arrived

between the 9th and 8th
centuries BCE,

first on the island
of Pithekoussai

and then later at Cumae
on the mainland.

By around 600 BCE, they founded
Neapolis, meaning "New City,"

a planned settlement
with temples and a theater

and a major port, as well as
a defined civic center.

Neapolis was
absorbed into the Roman Republic

in 327 BCE, but retained
autonomy for another 200 years,

allowing Greek customs
to persist under Roman rule.

From the 6th century CE onwards,
Naples transitioned

through Byzantine, Norman,
and Swabian rule.

From 1265 on,
under Angevin rule,

Naples flourished
as a dynastic capital,

notable for its
Gothic architecture

blending French, Greek,
and Arab cultural elements.

In 1889,
beneath the courtyard

of a 19th century palazzo
in Naples' Sanità district,

a baron digging for water

pierces the ceiling of
a long buried chamber,

uncovering one of the city's

most extraordinary
archaeological sites.

40 feet below
the palazzo, a steep staircase

leads to the Hypogeum
of Cristallini Street--

four rock-cut tombs
carved directly

into the volcanic rock hillside.

Each has its own
monumental entrance.

One is even framed
by ionic columns.

These entrances
originally opened

onto the ancient
necropolis pathway,

actively used between the 4th
and 1st centuries BCE.

Each tomb follows
a two-level plan.

The lower chambers built
in the Hellenistic period

contain carved stone beds,
statues, and symbolic offerings

consistent with traditional
Greek burial customs.

Later Roman adaptations
introduced niches for urns

and Latin inscriptions
on the upper levels.

In all, 700 artifacts
were discovered

reflecting the tomb's
extensive and evolving use.

After centuries
of activity,

flooding and mudslides
buried the necropolis

beneath layers of sediment,

eventually
concealing it entirely.

By the 1500s, the Sanità
was built above it.

Now, workers may have
encountered the site

in the 1700s, but even today,
its full extent is unknown.

We believe the necropolis
once held dozens of tombs.

The Hypogeum
of Cristallini Street

opened to the public
for the first time in 2022.

But key questions persist--
who was buried here?

And what do these
elaborate chambers tell us

about the ancient beliefs,
identity, and ramifications

of social status
in Hellenistic Neapolis?

The vivid frescoes
and symbolic motifs

inside the Hypogeum
of Cristallini Street

raises questions about
whether these tombs

were more than resting places.

The deepest and
most intact chamber, Tomb C,

is framed by fluted columns,
scarlet painted steps,

and elaborate frescoes.

The density of symbolic detail
raises the question,

was this space designed
for cultic ritual

or commemorative rites?

Dominating one wall is
a 20-inch limestone Medusa head,

a common protective emblem
in Hellenistic tombs

meant to ward off evil.

Nearby lies a silver wine jug

and meticulously
carved offerings.

These features imply
the chamber may have been

deliberately crafted to blend
symbolic protection

with rituals of remembrance.

Near the tomb's entrance,

there's this painted golden dish
that depicts two characters

who are believed to be
Dionysus and Ariadne.

Those are characters associated
with fertility, rebirth,

and divine ecstasy.

Now, there are also laurel
and myrtle garlands.

Those are plants that are
associated with Dionysus.

Unlike public ceremonies
conducted at the civic level,

Dionysian mystery cults
practiced private,

initiatory rituals for
individuals or small groups

seeking favorable afterlives.

Cristallini's iconography
may indicate

similar private rights
were enacted here.

500 miles east at
Amphipolis in northern Greece,

archaeological discoveries
provide clear evidence

of ritual spaces dedicated
to cult worship.

Excavations in 2024

beneath a later
Byzantine basilica

revealed a dedicated
cult building

reconstructed during
the 4th century BCE.

Archaeologists found
dense ritual deposits

including female figurines,
womb effigies,

oyster shells, and animal bones,

indicating sustained
cultic activities,

likely honoring a female deity,
possibly Artemis.

Amphipolis provides
definitive evidence

of cult activity--
votive offerings,

ritual objects, and a clear
devotional setting.

While artifacts were found
at Cristallini,

the most striking elements

are the carefully arranged
architecture

and evocative imagery

raising an important
archaeological distinction:

Is this a genuine cult space,
or a commemorative tomb

that only mimics
sacred ritual forms?

In 1968, about
50 miles southeast of Naples

at Paestum, the Tomb of
the Diver was discovered.

The tomb is dated
to around 480 to 470 BCE,

and it consists of five
slabs of limestone

forming this small
painted chamber.

The interior walls depict
young men crowned with laurel

who are eating and making music.

But the most striking feature
is the tomb's ceiling.

It shows this solitary figure
diving headfirst

into shallow water
framed by trees and by sky.

That image is unique.

It's unlike any other
from that time in history.

The burial contents
are unusually sparse,

with no human remains
or inscriptions.

This absence of typical offering
suggests that the tomb's meaning

may have relied heavily
on its painted imagery,

with visual symbolism itself

serving as a key form
of commemoration,

perhaps replacing
material offerings.

Interpretations
of the diver's imagery vary,

from metaphors on the soul's
passage into the afterlife,

to depictions of suicide.

Some even argue these scenes
were borrowed

from popular Attic face motifs,

and may not reflect
a fully developed

or unified funerary
belief system.

Cristallini,
by contrast, represents

a more integrated
ritual environment.

Its carved architecture
and mythic iconography

points to deliberate planning

aimed at shaping
commemorative practice.

But the limited evidence makes
it difficult to determine

which rites or beliefs, if any,
were actually tied to the space.

The architecture,
materials,

and detailed iconography
at Cristallini

hint at a particular
social standing.

The tombs
clearly reflect

high-status
decorative traditions

observed in the 4th century BCE
at Macedonian burials

and at Greek-speaking cities
across southern Italy.

You've got monumental facades,

you've got richly
painted interiors,

you've symbolic imagery--

all of that aligns with
their customs and beliefs.

So, given these parallels,
is it safe to assume

that these tombs
were commissioned

by the prominent
Greek families of Neapolis?

Hypogeum C exemplifies
this substantial investment.

Carved directly into the rock,

its furnishings
include stone beds

with intricate palmette
and geometric patterns

resembling inlaid
precious stones.

Painted pillows with carefully
detailed red stitching,

along with expensive pigments,

like madder yellow
and Egyptian blue,

reinforce the exceptional
resources of the tomb's patrons.

Perhaps the strongest
evidence of Greek patronage

lies in the Greek inscriptions
of personal names

and six headstones bearing the
word khaire, meaning farewell.

These inscriptions, coupled with
sophisticated design elements,

indicate a deliberate expression

of cultural identity
and elite status.

Over 450 miles south,
the tholos tombs at Pylos

highlight a different approach
to elite burial practices.

Excavations
at Pylos uncovered

two beehive-shaped tombs
15 feet underground

and dating back 3,500 years.

Although looted in antiquity,

the chamber floors were once
lined entirely in gold foil.

It was clearly intended as
a powerful visual statement

of wealth and prestige.

Look at these artifacts.

You've got Baltic amber,
you've got Egyptian amulets,

you've got a gold pendant

depicting the Egyptian goddess
Hathor, protector of the dead.

There's a pattern to these.

They are rare,
and they're imports.

Those two things suggest
that early rulers

deliberately displayed
objects like this

to broadcast their
trade connections

and their cosmopolitan tastes.

This outward-facing strategy

contrasts with Cristallini's
more narrow focus

that linked them back
to their Hellenistic roots.

At Cristallini,
elite status was asserted

not through
lavish foreign goods,

but through culturally specific
visual narratives, inscriptions,

and localized symbolic motifs,

indicating a tightly
defined community identity

rather than a broader
Mediterranean cosmopolitanism.

In 2023,
archaeologists uncovered

the remarkably intact
tomb of Cerberus,

dating to around
2,200 years ago,

just over 10 miles
west of Naples.

The tomb's
painted garlands

and vivid mythological scenes

include a rare depiction
of Hercules capturing Cerberus,

the three-headed hound
of the Roman underworld.

The tomb's impressive scale
and intricate imagery

suggest it was commissioned
by an elite family

for a prominent Roman patriarch
in ancient Liternum.

Inside, archaeologists
found libation vessels,

glass ointment jars,
and a strigil,

which is a grooming tool used
by ancient Greeks and Romans

in bath rituals.

Based on these findings,

it seems that the tomb's
"lavish" elements

were strategically chosen
to assert the social standing

and enduring legacy
of its occupant.

At Cristallini,
imagery of Dionysus

could also reflect elite status,

particularly for families
involved in the wine trade.

Because in Hellenistic
southern Italy,

Dionysus embodies
big-picture themes

like transformation
and immortality,

but he's also explicitly linked
to wine and rituals around wine.

So this imagery could be doing
two things at once here.

It could be signifying
spiritual aspirations,

but also professional
and economic identity.

The visual language
at Cristallini

corresponds with
philosophical ideas

circulating in southern Italy
at the time.

From 530 BCE onwards,
Pythagorean philosophy

was centered in southern
Italian cities like Kroton,

and likely influenced
local views of immortality,

cosmic order, and the afterlife.

Although a direct link
can't be established,

these ideas may have informed
how some elite community

used tombs to express beliefs
in harmony, identity,

and continuity beyond death.

Around 20 Hellenistic
tombs have been documented

beneath Naples'
Sanità district,

but the Hypogeum of Cristallini
is by far the most intact.

Still, questions remain
about the individuals

behind its construction,
their motivations,

and the precise beliefs
embedded in its design.

Deep inside central Iran's
Isfahan Province,

about six miles north of
the historic city of Kashan,

is the desert town of Nushabad.

Now, as I understand
it, the Persian name Nushabad

is traditionally translated
as something like

"city of cold, tasty water."

And listen, in this
part of the world,

cold water is gonna
taste really good.

The climate is very hot.

But Nushabad's 12,000 or so
inhabitants have been using

a freshwater spring at the foot
of the nearby mountains.

And for more than 1,500 years,
that underground water system

has supported not only
drinking water,

but also agriculture
and even public baths.

But the design of the
city itself is also ingenious.

Towering over the streets
are vertical towers

called wind catchers,
which are designed to harness

the slightest breeze
and funnel it indoors.

These impressive
structures have towered above

Nushabad's desert skyline
for centuries,

but in 2006, an accidental
discovery shines a light

on what lies beneath
this ancient city.

A local resident
in a nearby village

was digging a well
on his property

when he unearthed what appeared
to be an underground tunnel.

Upon closer inspection,

it was clear that this was
a man-made corridor

that had been cut
into the earth and rock.

By 2007, formal
excavations had begun,

and what they found
at the end of this tunnel

would blow your mind.

It's this Byzantine complex
of interconnected rooms

with three stories of narrow
hallways and stairwells

that led to this dense
concentration of hidden chambers

and canals going all the way
down between 13 and 60 feet.

Each room had a height
of approximately six feet,

which strongly suggested
they'd been designed

for human occupation.

But there didn't appear
to be a main entryway

into this underground city.

As the site was more
thoroughly investigated,

a number of secret entrances
were discovered.

These doorways were
cleverly concealed

within some of the town's
older residences.

The scale of
this thing is enormous.

It's estimated to be over
three and a half acres,

and it seems to have been dug
out continuously over years.

But who built it, and why?

Researchers
date the structure

by examining
its architectural details,

along with stone tools
and pottery

that were excavated
from the site.

Their analysis places
the construction

of this underground edifice
to about 1,500 years ago.

This was the era of
the Sasanian Dynasty in Iran.

The Sasanians were one of
the most influential empires

in that country's
entire history.

Under their regime,
academia flourished

and an artistic renaissance
began to bloom.

Archaeologists have found
evidence of expert metalwork

and gem engraving

from this period.

Nushabad itself
was situated

along a valuable trade route

between Tehran

and the Persian Gulf,

which was part of the Silk Road.

This made the city
a valuable stop

for travelers
and merchants alike.

To this day, there are ruins
of centuries-old inns

buried in
the surrounding desert.

But Nushabad's
geographical location

also made it
vulnerable to attack.

During the 7th century's
Muslim conquests,

the Sasanians were
crushed by the Arabs.

But evidence suggests the
underground city of Nushabad,

which had been built
during their reign,

continued to be extensively used
for hundreds of years.

The subterranean underground
world was locally known as Ouyi.

But despite
its incredible size

and 1,500-year history,
Ouyi had largely stayed hidden

from the modern world until
its rediscovery in 2006.

And the question remains, why
was it built in the first place?

A subterranean
complex hints at subterfuge,

and there may have been
a good cause for secrecy

in Sasanian Iran.

The kingdom adopted
Zoroastrianism

as its state religion,

and while there was tolerance
for other beliefs,

some did face
religious persecution.

One such religion might
have been Mithraism,

which was gaining
popularity in Rome

at the same time Christianity
was exploding across the empire.

Mithraism was inspired
by the Iranian deity Mithra,

and worshipers would congregate

at these underground temples
called Mithraea.

There's almost no literary
evidence of Mithraic practices,

but hundreds of these temples
have been discovered

in underground chambers

throughout the former
Roman Empire.

In the northwestern
part of the country,

the Mithra Temple of Maragheh
features multiple rooms,

domed ceilings, and
a grand entrance corridor.

It's possible Nushabad's Ouyi
also could have served

as a secret place of worship.

But there's been
no reported discovery

of any Mithraic artifacts
or iconography

at Nushabad's underground city.

And a dedicated Mithraeum was
usually only about 75 feet long

and 30 feet wide.

It would have held no more
than 20 or 30 people,

far fewer than the sprawling
complex buried under Nushabad.

The harsh living
conditions in the desert

may have been motivation enough

for the construction
of an underground city.

One obvious reason to
build a complex of this size

below ground is
to shield the people

from the punishingly hot weather
you get in that region.

The structure's cooler
temperature was achieved

by this brilliant series of
air ducts throughout the complex

that could circulate
the cooler air.

The complex appears
to have been built

around the freshwater spring
that was the town's namesake,

and it used water pipes
and canals

to move the water
from one place to another.

This was part of an ancient
Iranian water system

called a qanat, which delivered
groundwater to the surface

through a series of gently
sloping underground tunnels.

It's highly plausible that
the need to get cool air

and fresh water to its residents

in the most efficient
way possible

is what drove the design
of this structure.

And while
the structure itself may appear

too grandiose for such
a utilitarian purpose,

architecture during the time
of the Sasanians

could be over the top.

But the sheer scale of this
underground complex

betrays a larger,
more important purpose.

The secret entrances into
the underground suggest

that residents could quickly
and easily go into hiding.

But why?

The town of Nushabad
may have created

this mysterious habitat

as a means of escaping
an imminent threat.

Around 1220,
Genghis Khan,

the leader of
the Mongolian Empire,

marched his armies
into the Khwarezmian Empire

which included much
of present-day Iran.

Now because of
Nushabad's proximity

to a valuable trade route,
it was a likely target.

The city's giant underground
shelter could easily have served

as a wartime refuge
for its residents.

By entering through
secret entrances above ground,

the population could effectively
disappear from view.

And because of the access
to the spring water,

people could have sustained
themselves there

for weeks at a time.

There are also many
architectural details

throughout the halls
that were clearly built

for defensive purposes.

One of the more ingenious
features is the corridors

between the interconnected
rooms, which are often angled

to eliminate direct sight lines
between spaces.

This would make it much easier
to hide from your enemy,

or conversely,
it's the ideal space

to mount a surprise
defensive maneuver.

In certain corridors,

there's also evidence of
booby traps and disguised pits,

which could ensnare
unsuspecting intruders.

Whether it was
built in the time

of the Sasanians'
conflicts with the Romans

or during their later battles
with the Mongols,

the fact that this shelter
and water system

were hidden underground
strongly suggests

that safeguarding
Nushabad from invaders

was the main reason
it was built this way.

Today, researchers
believe that this

enormous structure may be even
larger than previously thought.

Currently,
locals and tourists can enter

the underground city through
an adjacent cistern,

but this isn't thought to be
the original entrance.

So there's a very real
possibility

that this underground
network of tunnels

may extend far beyond
the walls of Nushabad.

Many of the rooms
were amalgamated

in the centuries following
the Sasanian Dynasty,

and modern infrastructure, such
as water pipes, storage spaces,

and even toilets,
were eventually incorporated.

This complex is a wonder
of engineering

that was continually updated

right until the beginning
of the 20th century,

until it was reportedly
abandoned in the 1920s.

It took the accidental
discovery in 2006

for current generations
to bring their own ingenuity

and adaptations to this
incredible underground city.

Today, the site is
recognized as one of the oldest

underground structures
in the world.

And as researchers continue
their exploration,

new mysteries are likely
waiting to be uncovered

within Nushabad's
secret subterranean city.

Situated near
the center of Italy

and within 200 miles of iconic
cities like Naples and Florence

is the nation's capital, Rome.

Rome is one of the most
prominent centers of culture

and power in the history
of the world.

And there's a reason that
it's known as the Eternal City.

It's existed for
almost 28 centuries,

making it one of oldest
cities in Europe.

And within Rome, there's
the sovereign country

of Vatican City, which is
the administrative center

of the Catholic Church.

For centuries,
the Roman Empire was a colossus

of cultural and economic power.

At its height, it spanned
about 2 million square miles,

with its highly professionalized
military controlling territory

in Western Europe, the Middle
East, and Northern Africa.

At one point, Rome ruled
over 60 million people,

which at the time was more than
20% of the world's population.

Today, 1,500 years
after the fall

of the Roman Empire, the city is
an archaeological gold mine.

Priceless artifacts are pulled
out of there every year.

In 2016, the city is
in the middle of undertaking

an excavation
of a different kind.

The Metro C project is
a years-long expansion

of public transportation
from Rome's eastern suburbs,

but the construction of one
of its underground tunnels

leads to an unexpected
discovery.

Near the Aurelian
Walls on Rome's Caelian Hill,

workers came into contact
with a large structure

buried 30 feet below ground.

Archaeologists were brought in
to conduct their own analysis

and excavation and soon realized
that what they were looking at

was the remains of
a large military complex

spanning over 9,000 square feet

and containing
39 dormitory-style rooms.

Two years later,
they announce the discovery

of another mysterious building,

buried below the barracks
at a depth of about 40 feet.

It appears to be the remains

of a luxurious Roman house,
or domus.

Like the barracks, these remains
are remarkably intact,

but their lavish decor
stands in stark contrast

to the military building.

There's evidence
that suggests the home

was deliberately dismantled
and covered up.

The walls were raised and
the room seemed to have been

carefully and purposefully
filled with earth.

This is not your
typical Roman ruin.

This house appears to have been
intentionally buried.

So who lived in this place
and why was it buried?

As the excavation
continues, it becomes evident

that the domus was
designed for comfort.

The house covers an
area of about 3,000 square feet

with 14 rooms.

It also looks like the property
had a large courtyard

with a fountain
and a bath house.

Even by today's standards,
this was a pretty sweet pad.

The interiors of
the home are no less decadent.

Many of the rooms have floors

covered in
black and white mosaics

made from marble and gray slate.

And there are two rare
figurative mosaics as well.

One panel depicts a solitary
bird perched on a branch.

Another depicts two figures,
possibly deities,

who appear to be
locked in combat.

Further excavation
places the construction

of the house and the barracks
in the 2nd century BCE

during the reign
of Emperor Hadrian.

In this century,
Caelian Hill,

where the barracks
and domus were discovered,

was an area with a conspicuous
display of wealth and power.

The Roman emperor's
secret police,

known as the frumentarii,
were stationed here,

as were the emperor's
horse brigades.

The city's firefighters
and police forces

were also located
on Caelian Hill.

The hill was also
a fashionable neighborhood

for the city's aristocracy.

And given the amenities in the
courtyard of the buried house,

the mosaics and
the private bath house,

it's clear that
they likely belonged

to one of Rome's elites.

The fact that
the home was situated

within the barracks grounds
on Caelian Hill suggests

that the resident could have
been a Roman senator

with connections
to the military.

A politician
living in this domus

would have effectively had
their own private security force

living on the property
with them.

Is it possible that this
individual was caught

in some kind of intrigue
or political upheaval

and needed protection?

In 271 BCE,
Caelian Hill was home

to a violent uprising when
workers at the mint revolted.

The emperor implicated
several senators in the plot,

and they were eventually
put to death.

Could one of those senators
have been the owner

of the domus
behind the barracks?

If so, the burial
of his opulent home

may have followed
soon after his execution.

If this senator had
loyalists inside the barracks,

it's conceivable he could have
taken up residence there.

But maintaining a private army

in the middle of one of the most
powerful and influential regions

in Rome would hardly
have gone unnoticed,

nor would it have
been acceptable

to the neighboring
power brokers,

much less the leaders
of the military.

The burial of
the barracks and the domus

may have been a public erasure.

Edicts like this were well
within the powers of the state.

There was this formal
punishment in the Roman world

called damnatio memoriae,

which means
"condemnation of memory."

And this was a death penalty,
but it was more than just that.

It also removed a person
from the public record.

A perceived traitor within the
ruling class would be executed,

and then their name would be
removed from any inscriptions

and public monuments.

Their statues and their property
would also be demolished.

Is it possible that
this is what happened

to the owner
of the mystery house?

The buried villa
certainly suggests some kind

of deliberate erasure
has taken place.

Whoever lived in the domus prior
to its burial may have been

under house arrest and watched
over by military guard

until his scheduled execution.

However, there is
no physical evidence

to corroborate the theory.

Ultimately,
the best explanation

for why this luxury home was
nestled on military grounds

may be the simplest one.

The proximity
of the luxury home

to the military barracks seems
like it should tell us a lot

about who lived here.

In this context,
it seems highly likely

that this was
the private residence

of the commanding officer
of the adjacent barracks.

It wouldn't have been
unusual for a Roman general

to have lived in luxury.

A commander's residence was
known as a praetorium,

and it was essentially
the nucleus

of any military facility.

A praetorium that was unearthed
at Castor in Cambridgeshire

was truly palatial and
one of the largest structures

from the Roman Empire
ever discovered in England,

far exceeding the size
of the mysterious villa

on Caelian Hill.

If the buried domus
in Caelian Hill really was

the home of a high-level
military officer,

that would make it the first
time within the city of Rome

that a military barracks
has been found

with the private residence
of its commander.

But the mystery of why

it was deliberately
buried remains.

It would have
taken a lot of effort

to cover up the domus, so what
was the motivation to do so?

Both structures have now been
painstakingly taken apart

and removed piece by piece;
but the plan is to rebuild them

when the transit stop
is completed.

Romans of today will be
able to puzzle over the remains

when the domus and the barracks
are reinstalled

near the metro station.

The questions
surrounding the barracks

and its neighboring villa
may never be fully answered.

For now, it seems
the people who buried

these mysterious structures
have successfully erased

their true origins
from Roman history.