Original subtitles

NARRATOR: A series of storms reveal mysterious objects

off of England's coast.

- He had always seen a bump on the seafloor there.

But something about it seemed to have changed after the storms.

ANTHEA: It's a pile of rocks.

But there are also these round things laying on the seafloor.

What are these?

NARRATOR: A massive earthquake triggers a tsunami

in ancient Greece.

- A giant wave submerged the city,

covering it up entirely, with likely only olive trees sticking up

through the water's surface.

DAN: Incredibly, the sonar picks up ancient port infrastructure,

but also what looks like the remains of ten shipwrecks

along the shoreline. So is this the port of Helike?

NARRATOR: An unprecedented drought

in Mexico leads to the discovery of a strange structure.

- The grey walls of a remarkably intact ruin of some sort.

And it's a building of considerable size.

- So what was this place?

NARRATOR: All over the world,

incredible discoveries are being revealed

by devastating events -

floods, earthquakes,

draughts, hurricanes,

volcanic eruptions.

Trails of destruction expose long lost mysteries.

This is Discovered By Disaster.

NARRATOR: In March of 2019, a low-pressure area

over the western Atlantic was picked up by the jet stream,

a deadly combination that created Storm Gareth,

which began to roar towards Great Britain with menacing ferocity.

- When Gareth made landfall in the UK,

it was gusting at 75 miles per hour.

There were downed trees, power outages, and flooding.

- Just over a month later, with the UK barely recovered from Gareth,

another storm - Storm Hannah - struck.

Similar to Gareth, but with gusts up to 82 miles per hour.

NARRATOR: Shortly after the passing of Storm Hannah,

a small boat is on its way to Poole Harbour in Dorset, England,

when the captain notices something on the scanner

about a mile offshore.

- He had always seen a bump on the seafloor there -

it had been marked on navigation charts since at least 1982.

A pile of rocks, is what everyone said - covered in silt, of course.

But something about it seemed to have changed after the storms.

- There were fish hanging around -

that's what was showing up on the scanner.

And if you've a structure underwater where fish can hide,

fish will come and hang around there because they feel safe.

So maybe there was more to this pile of rocks than meets the eye.

NARRATOR: A team of maritime archaeologists

from the local university are summoned to the site,

and hit the water to investigate.

At a depth of only about 32 feet,

the divers find a large bump, as expected...

and it's no longer covered in silt.

- It's a pile of rocks.

But there are also these round things laying on the seafloor.

They look like thick stone bowls -

at least 10 of them, of various sizes, scattered about.

What are these?

JAMES: The divers bring one of the objects to the surface.

It's awfully thick and heavy for a bowl.

It's got what looks like a little pour spout

at one point along the edge,

and a couple of what might be rudimentary handles.

And it looks as though it had been in the seawater for some time.

ANTHONY: As soon as I look at that, I think,

"I've got something like that in my kitchen."

But it's not a bowl; what I have is a mortar and pestle,

used for grinding seeds and grains.

NARRATOR: Mortar and pestle sets are readily available online

and in culinary shops.

Usually made of granite or marble,

they typically have a smooth edge or handles.

While some may have pour spots.

- But why would a bunch of mortars be here?

Were they dumped? Or did they fall overboard while being shipped?

ANTHONY: It's odd that there aren't any pestles, though -

the part you use to do the grinding.

The only thing we can think of is, lots of pestles are stone,

but some are wood. So maybe these were all wooden?

So, if a shipment fell overboard,

after the cardboard would have gotten soggy and dissolved,

any wooden pestles would have just floated away.

NARRATOR: The divers return to examine the other mortars

and in the process they make another discovery.

- Sticking out from under the large pile of stones

are long planks of wood.

These are quite large - roughly about 10 inches wide,

by two inches thick, and many feet long.

There seem to be around 16 of them,

edge over edge - their edges overlap,

like the wooden siding on an old house.

- Could these be the remains of an old marina

or a dock or boathouse?

But this is a mile offshore.

And the biggest mystery would be

how would the wall of a structure like that

end up 32 feet down,

pinned under a pile of rocks?

- Ultimately, we realise these aren't just planks;

they're strakes which are hull planks.

This is the wreck of a wooden ship.

- This would explain that big rockpile.

Those stones could have been ballast

to help balance the ship and keep it stable.

Modern ships often have water tanks deep in their holes,

which are used to adjust the ship's balance

and make up for changes in cargo loading.

But a lower tech method is just to use rocks,

which the crew then moves around by hand as necessary.

- So, a ship sank, broke up, and most of it floated away.

But part of one side of the hull was pinned down by the ballast stones,

and that's what we're seeing here.

NARRATOR: Probing the area further,

the maritime archaeologists find a stempost -

the main piece of timber that goes up along the middle

of a ship's bow, and a piece of floor timber.

- Based on the measurements and the shapes of these elements,

this vessel may have been close to eighty feet long

and about 24 feet wide.

Quite a big, substantial ship, really.

It might have carried a crew of about 20.

NARRATOR: There is no wreck marked

on the navigational charts at this spot-

only "Obstruction 3g" - referring to the pile of rocks.

- We know this ship has been here since at least 1982,

because Obstruction 3g was already on the charts back then.

But, how long has this wreck really been here?

NARRATOR: The divers locate a large stone slab that's unnaturally flat

with straight edges.

When they brush the silt away, another surprise is revealed.

- There's a Christian cross, chiselled in relief.

This is a wheel-headed cross.

It's a remarkable piece of stonework, impeccably handmade.

You can see the chisel marks.

This is a gravestone slab.

- There's also a second slab, right near the first one.

This one's of a different design, a splayed-arm cross.

Both slabs are remarkably undamaged.

NARRATOR: The slabs are too large to bring up safely...

..so instead the divers bring up more of the mortars.

- There are a number of designs and shapes,

but all the mortars are stone.

With one of them, you can clearly see

fossilized fish bones in the rock,

and that tells us these mortars are made of Purbeck.

JAMES: Purbeck is a sedimentary limestone rock

that would have formed between around 140-150 million years ago.

It's essentially fossilized snails

with other vertebrate and crustacean fossils mixed in.

NARRATOR: The Isle of Purbeck is on what's known as the Jurassic Coast -

a 95 mile stretch of English coastline

within the counties of Dorset and Devon

with an extensive limestone beach

that's been quarried since the Iron Age.

- So the pile of boulders probably wasn't just ballast,

it may also have been part of the ship's cargo.

These boulders were all Purbeck limestone

and were probably being shipped somewhere.

NARRATOR: Purbeck marble is a rare, particularly-hard variant

of Purbeck stone.

It can be brought to a high, luxurious polish,

which made it valuable and much sought-after.

- While regular Purbeck limestone is still being quarried today,

the more rare Purbeck marble was

quarried out in about the 15th century.

They essentially ran out of it.

So that means the wreck must be at least around 600 years old.

NARRATOR: To get a more accurate determination

of the age of the ship,

a dendrochronological analysis is performed -

a process that can ascertain how old a piece of wood is

by matching variations in the thickness of its growth rings

with historical data regarding seasonal climate changes.

The results are shocking.

- The trees these planks were cut from

grew between the years 1242 and 1265.

So this ship was built about 750 years ago!

- This is the oldest English shipwreck site

with any surviving hull remains.

Before this one, there were no known wrecks of any seagoing ships

in the UK from between the 11th and 14th centuries.

So how could the wood have survived this long under water?

ALISON: Ultimately, it's probably due to the silt.

When this ship went down, the heavy Purbeck stones it was carrying

pinned one side of the hull deep into the silt.

And the local currents likely covered it all over very soon after.

The silt kept oxygen out,

and a lot of burrowing sea creatures away as well.

- Now the presence of those grave slabs

makes a lot more sense, as well.

Both those styles - the wheel-headed cross

and the splayed-arm cross -

are known to have been in use in the 13th century,

which fits perfectly with our estimated age of this wreck.

NARRATOR: Researchers may be able to learn more about the wreck one day,

when they remove some of the Purbeck stones and reveal what lies beneath.

For now, they're focusing their energies on preserving what's there.

- The whole reason it's believed this wreck has lasted

seven and a half centuries underwater

is that it was covered up with silt for most of that time.

Now that Storms Gareth and Hannah cleared that silt away,

it's very vulnerable to shipworms.

NARRATOR: An important first step has been taken:

The government has assigned the wreck

the highest level of protection,

acknowledging its value, and the importance of preserving it.

If archaeologists can one day manage to raise it

and place it and its artifacts into a museum...

who knows how many more centuries they might last.

In the year 373 BCE,

a powerful earthquake hit the southwest shore

of the Gulf of Corinth,

devastating Greece's Peloponnese peninsula.

- On the north shore of the peninsula,

the residents of the ancient Greek city of Helike

were sent into a panic.

As they went about trying to save themselves,

it is believed that the earthquake triggered a tsunami,

which then went on to hit the city.

- A giant wave submerged the city, covering it up entirely,

with likely only olive trees sticking up

through the water's surface.

The ancient Greek historian Strabo would write

that an emergency task force of 2,000 men was organised

to help any survivors, yet none were found.

- The destruction was so complete, that for over a thousand years

we have not known where this city was actually located,

despite the fact that Helike's ruins are mentioned

in several ancient texts.

Nor could we piece together the puzzle of what really happened

on that horrible day in 373 BCE.

- This is eerily reminiscent of another mythical tale,

that of the Lost City of Atlantis.

Writing just a few years after the disaster,

the Greek philosopher Plato told of an advanced civilisation

that had angered the gods to such an extent

that they were punished severely.

The gods destroyed their entire civilisation

with an earthquake and covered it with the sea.

JAMES: Atlantis was lost, never to be seen again.

Because the story of the two cities are so similar,

could the destruction of Helike have provided inspiration

for the story of Atlantis?

NARRATOR: In the years following the disaster at Helike,

several ancient scholars would visit and write about the city.

Strabo wrote that 150 years after the event,

the scholar Eratosthenes visited the area

and was informed by local sailors that submerged in the "poros",

a bronze statue of Poseidon could still be seen.

- A poros is an ancient Greek word that we now interpret

as meaning a "narrow passage of water".

And in the context of how it was being used by Strabo,

we assume that the statue of Poseidon

is now lying at the bottom of the Gulf of Corinth.

- Helike's patron god was, in fact, Poseidon -

the Greek god of the sea and, as irony would have it,

also earthquakes.

For this reason, the collective worship of him

would have been central to the city's identity.

- It's strange, though,

because although we know a fair amount about Helike,

no archaeologist has been able to locate it.

Despite several attempts,

focusing mostly on the Gulf of Corinth's seabed,

nothing, not one clue, has ever been found.

So what could be the reason for this?

NARRATOR: Determined to find out, a Greek archaeologist uses sonar

to scan the ocean floor of the Gulf of Corinth.

- Incredibly, the sonar picks up ancient port infrastructure,

but also what looks like the remains of ten shipwrecks

along the shoreline.

Now ancient texts specifically mention

that there were ten Spartan vessels at anchor

on the day of the disaster, so is this the port of Helike?

JAMES: It's certainly an interesting find,

but the possible remnants of a port doesn't really tell us much at all,

especially when there are no ruins of a city next to it.

DAN: Luckily, several ancient writers

were just as fascinated by Helike as we are.

In the 2nd century CE,

almost 500 years after the disaster,

the Greek writer Pausanias gave some more specific location details.

ANTHEA: He wrote that Helike was four miles east of Aigion

and three miles from the Cave of Heracles -

a site of worship for the ancient Greeks.

When you take these distances and place them on the map,

they line up pretty well with the port infrastructure and wrecks.

So could it be that Helike was here, right on the coast?

NARRATOR: The archaeologist revisits the ancient texts for more clues

and something gives her pause.

- The word "poros" traditionally had been assumed

to refer to the Gulf of Corinth,

but no other texts cite it in that manner.

So it's possible that it may have been referring to an inland lagoon,

or even a lake.

- This seems to be in line with what Strabo said

about the submersion of Helike. He wrote...

- Stadia is a unit of measurement used by the ancient Greeks.

One stade is roughly 600 feet, meaning that, according to Strabo,

Helike was located a little over a mile inland from the sea.

- So does this mean that when Strabo was shown the statue of Poseidon

lying underwater, he was actually looking at the ruins

of a city submerged by an inland lagoon?

NARRATOR: There are no inland lagoons or lakes in the vicinity

of where the archaeologist's sonar picked up the possible port remains.

- This "poros", or inland lagoon, definitely existed.

We know that because the ancient writers talk about it.

But here's the catch - Pausanias wrote that part of the lagoon

had dried out and covered up the ruins of Helike.

This area can get hot and dry,

so is it possible that the lagoon just dried up?

- Although there are no inland lakes here, there are two rivers:

the Kerynites and Selinous.

And the thing with rivers is they carry a lot of sediment with them,

and over time, the build up of this sediment can change the landscape.

- So what probably happened is that over time,

the annual flooding of the rivers

and the dispersal of silt into the lagoon eventually covered it up.

This is why some 500 years after the disaster,

Pausanias described the lagoon as partially covered up and dried out.

NARRATOR: Armed with this new information,

the archaeologist begins to drill boreholes

in the area between the two rivers.

The excavation yields results:

cobbles covered with clay mortar.

- These are the remnants of old walls.

They are in a sorry state,

but that's to be expected if they are from Helike,

having experienced an earthquake and tsunami,

Pausanias mentioned that although they were heavily eroded,

he could still make out the city's walls under the water

in the area that wasn't dried out.

Could these be those very walls?

NARRATOR: As the excavation continues,

the archaeologists hit the jackpot.

- They found coins!

Which are a wonderful archaeological find

because they can provide a pretty exact time frame

for when they were in use.

After all, coins are only minted for a limited amount of time.

DAN: These coins are incredible.

Some of them depict a trident

with two dolphins swimming on either side,

and then a laurel wreath tied at the bottom.

And if you flip it over, on the other side

is the face of a guy with a beard.

- The trident, the dolphins and the man on the back all give it away.

This is none other than Poseidon, the patron god of Helike!

These coins are extremely rare, and would have been minted

sometime in the 4th century BCE.

- So this must be the site of the ancient city of Helike,

but what about the disaster?

Did it really happen?

NARRATOR: The archaeologists working at Helike discover

the site's destruction layer.

ALISON: The destruction layer is a term used in archaeology

to define a particular section of the excavation area

that contains significant amounts of a period's material culture,

which means any and all objects produced or used by humans.

It can also provide evidence of what the geological

or environmental conditions were that led to the destructive event.

- For this reason, other than the deposits from 373 BCE like pottery,

roof tiles and stones from demolished buildings,

the destruction layer should also contain sedimentary evidence

of a tsunami having hit. But there is none.

- Until now we have just assumed, owing to the ancient texts,

that the destruction of Helike was due to a tsunami.

But it's worth considering the possibility that something else

may have destroyed that city.

NARRATOR: At a depth of nine feet below the ground,

three sedimentary layers catch the archaeologists attention.

- There are two mudflow deposits

situated above and below a gravel bed.

A mudflow is a large amount of water that contains debris,

like rocks, organic material and silt.

The fact that there are two mudflow deposits here indicate

that a massive wave of sediment and water overwhelmed the city of Helike

- not a massive ocean born wave.

- This is interesting, because it is well known that rivers in this area

are prone to natural damming.

That's when a landslide blocks a river,

prevents it from flowing normally and, as a result,

when the banks flood, water goes everywhere.

ANTHEA: But of course, it's not just water,

it's tons of and tons of debris and who knows what else.

So what could have happened in 373 BCE

is that the earthquake triggered some massive landslides

in the mountains above Helike,

dammed the two rivers flowing on either side of it,

and then when these dams burst, catastrophe struck.

- An already heavily damaged Helike would have been hit by a flood

of mud and debris that would not only would have proved fatal

to many of the earthquake survivors,

but would also have inundated and drowned the city.

NARRATOR: For the next thousand years,

people from far and wide marvel at Poseidon's submerged city...

..the Greek god of water and earthquakes,

reminding everyone of his power.

NARRATOR: Chiapas is Mexico's southernmost state,

and an area that has endured

a seemingly endless string of disasters

going back centuries.

Ancient quakes and plagues killed thousands;

floods, droughts, and locusts destroyed crops

bringing poverty and famine.

- But the mid-20th century promised relief

from the cycle of droughts and flooding

with the construction of The Malpaso Hydroelectric Dam...

..whose Nezahualcoyotl Reservoir

would ensure a stable and lasting supply of power and water.

- From the start, this dam claimed some heavy sacrifices.

The reservoir submerged vast amounts of rainforest;...

entire towns and a number of priceless archaeological sites.

- Mexico currently on gets only 40% of the rainfall it got

when construction of the Malpaso Dam began in 1958.

And right now, the water level at the Nezahualcoyotl Reservoir

is down to about a hundred feet below its normal capacity

and still dropping.

It's a dire situation

and a significant problem for the local tilapia fishery.

NARRATOR: In March of 2023,

those who went out on the reservoir looking for fish

would have seen something remarkable.

- The grey walls of a remarkably intact ruin of some sort.

And it's a building of considerable size -

the walls are about 30 feet high,

it's 183 feet long, and 42 feet wide.

- The facade is entirely of red brick,

which means they were likely made by hand from clay

and baked in a high-temperature oven called a kiln.

The rest of it is masonry -

boulders of various sizes

that we can presume were collected from the river

whenever this thing was built.

So what was this place?

NARRATOR: Features of the building bear a notable similarity

with other old buildings found in Mexico...

..including some notable courthouses

built during the Spanish colonial era.

- There's a portico, a large porch-like area at the front of it,

which is a common feature of old courthouses

and other public buildings.

On the walls inside are the remains of stone corbels,

which are features that would have held wooden beams

to support the ceiling of this structure.

- There are palaces that share some of these architectural features too,

lots of different buildings might.

We also see what appears to be the remains of some kind of tower,

but again, lots of building types have towers.

- But finally there's something definitive.

On the sides of that arch,

there are two niches, flanked by small columns.

And there are faint relief images in the mortar.

One of them looks female.

And then on the inside of the tower is inscribed A. MARIA.

Like Ave Maria, the Virgin Mary.

So could this have been a Catholic church?

NARRATOR: Careful investigation of the rest of the building

reveals the remains of a small architectural feature

that's only present on one side of the interior.

DAN: Toward the back of the building, on the left side,

there are these two enclosed spaces side by side.

One of them is about three feet wide,

the other one is just over two feet wide,

so each one is about the size of a person.

And there's a small opening in between them.

It looks like a confessional,

which would mean this temple is a Catholic church.

NARRATOR: Searches of the site using metal detectors yield coins -

one dated all the way back to 1828.

- So we know the church is likely at least that old, about 200 years,

but when, exactly, was it built?

NARRATOR: Nine miles northeast of the church

is the Convent of Santo Domingo de Guzman, in Tecpatan.

- This convent has a temple attached to it.

That temple, and the church that appeared in the reservoir,

are both masonry buildings, so constructed of stone,

and both were built in the Renaissance style,

that is using classical design elements:

A symmetrical facade; Roman or Greek columns;

semi-circular arches over windows and entrances.

- In fact, the temple in Tecpatan and this newly-appeared church

share so many features

it looks like they might have been designed by the same architect.

Right down to a bunch of the finer details.

NARRATOR: The frame of the confessional

and the passage to the sacristy, or vestry,

at the back of this newly-found church

are of the same design as the one in Tecpatan.

- And both of them use ribs,

which are arches of masonry that form a supporting frame.

They are used in the vaults and recesses under the arches,

over the doors, or the back of the main altar.

- The town of Tecpatan itself has existed continuously

since the time the convent was built,

so the convent's and its connected temple's history

has been well-documented.

It was established in 1564.

Could the church that just rose up out of the reservoir

also be four and a half centuries old?

- Well, about four decades before the temple in Tecpatan was built,

a world-changing event occurred.

The Spanish conquistadors arrived in 1519 and conquered Mexico.

So in the eyes of the Spanish,

all of the land - and all of the people on the land -

were under Spain's dominion.

And they took careful inventory of what they found there.

- The Spanish were aware of a town at this site called Quechula,

and the inhabitants of Quechula were the Zoque people.

NARRATOR: The indigenous Zoque people have lived throughout Chiapas

and the Isthmus of Tehuantepec -

and some of the State of Tabasco, since about 3,800 BCE.

- But now, subjugated by the new Spanish settlers,

the Zoque people suffered oppression,

abuse, disease and famine,

and after years of that, their numbers started to decline severely.

- The Spanish monarchy could see this situation wasn't sustainable,

and they weren't motivated by being kind to those people.

They were motivated by the fact that the Zoque

were their principal workforce in the area

and they wanted to maintain them.

So they wanted to do anything they could to avoid a rebellion.

And that is why, ironically, Spain was trying to curb the abuse

of the indigenous people so they could take better advantage of them.

But the thing is, the Spanish colonists on the ground

weren't gonna implement all these changes.

They needed someone else who could.

ANTHONY: The temple at Tecpatan is a Dominican church.

In 1545, Dominican friars were sent from Spain to Chiapas

to watch over the Zoque and protect them from mistreatment,

but also to make sure that they stayed in line.

NARRATOR: The Dominicans are a religious Order

of the Catholic Church,

founded in the early 1200s.

They were named after their founder, St Dominic,

but their name is also a play on words -

the Latin "Domini canes" means "dogs of the Lord".

- In Tecpatan, at that time, the Dominicans' purpose was

to try and protect the Zoque people

from the worst abuses of the Spanish settlers,

and to convert the Zoque to Christianity, at the same time.

NARRATOR: Immediately upon their arrival,

the Dominicans worked to establish centres

where this conversion to Catholicism could be carried out.

And that required the rapid building of churches

in Tecpatan, and elsewhere.

- So the construction of the church at Quechula

would have been overseen by the Dominicans,

and likely also by some Spanish soldiers,

but the Zoque people would have been the ones tasked

with doing all of the hard labour to build it,

stone by stone, and brick by brick.

ALISON: The Catholic church had grand plans for this region.

They imagined it might become a major population centre,

which is why they felt it was so important to build this temple here.

NARRATOR: But the Dominicans' own records suggest

that vision never came to fruition.

This Church may never even have had its own priest;

it had to rely on occasional visits by the priests from Tecpatan.

- And the Church has no records of any activities after the 1770s.

So as far as we can tell, the temple was abandoned around that time.

The question is why?

DAN: In the first two centuries after the Spanish conquest,

life for the Zoque people did not get appreciably better.

They had to pay extremely high tribute to their colonisers,

and thar kept them in a cycle of poverty and forced labour.

- By the 1770s, all this came to a head.

Throughout that decade,

we find records describing repeated infestations of locusts

that would have decimated maize and bean crops

and caused widespread famine.

NARRATOR: The Zoque people, subjugated and abused,

had been living a miserable and precarious existence

up to this point.

This unprecedented string of disasters

drove their numbers further downward.

- So that would explain the decrease

in the size of this church's congregation.

But sometimes people hold more tightly

to religion when times get tough.

So why at that time would this church have been abandoned?

NARRATOR: A team of archaeologists summoned

to the newly discovered church are doing excavations

when they discover something shocking.

- They find two pits full of human bones!

In the first, a layer of mixed, fragmented bones

and in the second, layers of remains over two feet deep.

AMMA: No evidence of cuts or stabs wounds or unnatural breakages

were found on any of the bones.

So these people didn't suffer violent death,

as you might see in a battle or rebellion.

- This was a relatively small parish,

so it's kind of weird to have such a large number of human remains

because you don't have that many people in a congregation

or community to begin with.

NARRATOR: Records show that between 1773 and 1776,

a series of plagues swept through Chiapas,

which would have decimated the population.

- This is an ossuary.

Victims of a plague would have been buried hurriedly upon death,

and later, when it was deemed safe,

their bones would have been collected

and laid to rest here in these ossuary pits.

So, these plagues may well have been the reason

this church was ultimately abandoned.

- Over the next nearly 200 years,

from the 1770s to the late 1950s when the reservoir swallowed it up,

there was plenty of time for this once-magnificent building to decay,

left to the elements and forgotten.

NARRATOR: The temple's history may be one of subjugation and suffering,

but many now simply see it as an impressive piece

of ancient architecture that's hung on for four and a half centuries,

only to make a miraculous reappearance

due to the drought that ravaged Mexico in 2023.

Kerman Province in the south-east of Iran is square along the path

of the planet's dust belt and prone to frequent and severe sandstorms.

In March of 2017,

just at the very start of peak sandstorm season,

a massive storm takes the region by surprise,

leaving many with no choice but to take cover.

- A big sandstorm can change the landscape.

Sand dunes that might fill dozens of dump-trucks

are basically lifted up into the air,

layer by layer, and redistributed elsewhere.

NARRATOR: After the storm has passed, a person travelling

near the small town of Fahraj on the eastern edge of the province,

notices something unusual in the sand.

- There's a large number

of earthenware pottery shards scattered in the sand.

Now, it should be noted that they've been making

pottery in this part of the world for thousands of years,

and they're still making pottery here,

including in the old, traditional styles.

So a find like this could be very, very old

or it could be relatively recent and just litter in the sand.

NARRATOR: According to established government protocol,

experts are dispatched to the site.

By the time they get there, something else,

much bigger, has been found.

- Poking up through the sand is the top of an archway.

This site may have been an habitat of some sort,

like a residence, or a palace; it may have been a facility.

It may also be a part of something much larger.

NARRATOR: Iran's authorities take no chances.

Military personnel are assigned to guard the site,

and keep watch for looters.

- The heavy security is due to something that happened

a couple of decades earlier with the discovery of another site,

south of the city Jiroft.

So, about 80 miles southwest of Fahraj.

- In 2001, a large number of beautiful artifacts just started

turning up in the antiquities market with no explanation.

Fine ceramics, drinking vessels, distinctive jewellery,

game boards, even weapons.

Often the provenance was just given as 'from Central Asia'.

NARRATOR: The police were notified, and by late 2002,

had arrested a number of traffickers

who then led them to the looted site.

- The site initially appeared to have been an ancient necropolis -

an elaborate ancient burial site.

But when archaeologists made a proper excavation of the area

they discovered structures the looters had been unaware of:

an enormous brick wall surrounding a citadel.

This was an entire ancient city!

NARRATOR: Further excavations unearthed intricate carvings

made of semi-precious materials like chlorite and obsidian.

Tools, sacred objects and decorative pieces were also discovered.

- There were also clay tablets with writing systems

we had never seen before.

Think of what that means:

A system of writing that no living expert is familiar with.

JAMES: Dating of the Jiroft site

showed it was established 5,000 years ago.

This was a distinct ancient culture

that scholars had never been aware of

and never previously found any evidence of.

- This is probably why the authorities were taking no chances

with this new site at Fahraj.

Because with it being less than a hundred miles from Jiroft,

you have to wonder: are the two sites connected?

NARRATOR: Under military-grade security,

excavations at Fahraj continue

and take a surprising turn with an unexpected discovery.

- They find bone fragments!

Now, it's quite common for human remains to be confused

with those of animals - particularly if they're fragmentary and very old.

So the question is - are they human bones?

NARRATOR: When the inside of a bone is observed closely,

structural units known as osteons are evident.

In humans, osteons tend to be scattered and evenly spaced,

whereas in animals they tend to be arranged in rows,

or rectangular structures.

When all that's available is bone fragments,

sometimes this is the best way to make a determination.

- Whether the attending archaeologists were looking at

osteons or at structure, when examining the fragments,

they determined these are human remains.

So we've got human bone fragments alongside pottery artifacts.

Could this have been a necropolis,

contemporaneous with the one at Jiroft -

active and in use around the same time?

- The short answer is no.

Dating of the pottery and bones found at Fahraj

put them possibly from somewhere during the Islamic Middle Ages,

which were between 661 and 1508, CE.

So, If these results are correct

then this site isn't nearly as old as Jiroft.

NARRATOR: As the excavation at Fahraj expands in scope,

the archaeologists make several surprising finds.

- They unearth tiles and ancient brick walls.

But what's really interesting is that they discover

long cylindrical tubes made out of earthenware.

They're flared at one end, so they fit into one another, end-to-end.

And they've been laid almost horizontally on a slight incline.

What are these?

- Something similar was discovered at an archaeological site

in Badreh County in the west of Iran

and it was determined that they were 5,000 year old pipes

for carrying water.

- Water pipes tell you two things:

One, the people at the Fahraj site

had the technology to move water that way,

and two, they had the need to move large amounts of water.

Meaning a large population.

- The pipes would have to have been linked to a source

capable of supplying a continuous flow of fresh water -

almost certainly a kariz.

NARRATOR: Kariz are an ingenious piece of ancient engineering

that can transport water underground for miles.

It's believed they were invented in Iran about 3,000 years ago.

- They're a remarkable example of the ancients' understanding

of engineering and geology.

With a kariz, a well is dug high up in an alluvial fan,

which is a geological formation that contains groundwater.

It has to be where the highest point of the water table

is higher than where you want to get the water to.

That becomes the mother well.

The builders then chart a course

back to where they want to access the water,

which might be up 30 miles away.

They dig a series of wells, strictly as access points.

And along the bottom of them all,

they dig a gently sloping tunnel called a koshkan

which is what carries the water.

And just like that - where your tunnel emerges from the ground,

it's like a natural, free-flowing spring.

JAMES: In Fahraj, it's likely that water from a kariz was distributed

by the earthenware pipes, supplying clean water for hundreds,

or even thousands of people.

So it's entirely possible that there's an ancient city

under the desert waiting to be discovered.

- Iran's cultural heritage organisation

is keeping an tight lid on their excavations.

But one statement that's intriguing is that they said

there's no precise data on the site's age and history,

because it's the first time that such ruins have emerged.

NARRATOR: Whether or not there's a lost ancient city at Fahraj,

and just how old it might be remains a mystery.

But one thing is certain - there's something there,

hidden for centuries and finally exposed

by the shifting of the desert's sands.

Subtitles by Sky Access Services