Original subtitles

Beneath the Mediterranean,

forgotten for millennia,

an entire city lies buried.

A snapshot frozen in time.

Heracleion,

a major city, a great port,

and one of the most significant in all of Egypt.

Yet, this real-life Atlantis

seems to have disappeared in an instant...

..leaving few clues that it ever existed.

Now it's finally revealing its secrets.

Incredible artefacts...

perfectly preserved beneath the sea

are at last allowing us to tell the extraordinary story

of this mighty city.

This is... So beautiful. ..a masterpiece. It is indeed.

Spectacular finds open a unique window

into the time of the Pharaohs and reveal this lost city

as one of the most important in Egyptian history.

2,500 years ago, the Ancient Egyptian city of Heracleion

stood here on the mouth of the River Nile.

Now it lies submerged off Egypt's Mediterranean coastline.

I'm leaving modern Egypt behind and travelling 6km offshore

to where the ancient shoreline used to be.

It's remarkable to think that this sea was once land

and that all around me was once a legendary port.

This is the place that Helen of Troy and her lover, Paris,

visited before the Trojan War.

It's where the god Heracles first set foot in Egypt.

But for centuries the city lay forgotten,

thought to be nothing more than a myth.

Until it was rediscovered 13 years ago

by French underwater archaeologist Franck Goddio.

THEY CONVERSE IN FRENCH

On the bottom of the sea bed, Franck discovered a city wall...

..and behind it the remains of a vast Ancient Egyptian temple...

..with ornate stone columns.

We have here one of the columns of the temple.

It's made from limestone

and it's absolutely huge!

But the temple was just the beginning.

Lying beneath the sea are walls,

stone structures, ancient inscriptions.

Bronzes, ceremonial vessels, gold, jewels and coins.

And the largest collection of ancient shipwrecks ever discovered.

The city of Heracleion was no myth.

As an archaeologist, I've worked all over the world,

but I've never had the opportunity to have access

to such a fascinating site as Heracleion.

Only now is the excavation

unravelling the mystery of this remarkable place.

An entire city, temples, houses,

public buildings untouched for millennia.

It's a unique window into Ancient Egypt

at a crucial time in its history.

We rarely get the opportunity to study a site

that extended for such a long period of time.

Heracleion existed for over 1,000 years,

it was occupied from the late-Pharaonic period, the end of the great pharaohs,

through to the arrival of Alexander, the Hellenistic period.

And I'm interested to know what the role of this port city was

and the role it played in the lives of the people of Egypt.

Franck and his team

are painstakingly mapping and surveying the whole site.

Heracleion was built on islands

and fractured with waterways and harbours.

How big you think it was overall? Overall, we have a city of 1.8km by 1.2km.

Oh, OK. It's a huge city.

So Heracleion must've been a significant city,

but what made this city so important?

A clue may lie in the number of temples discovered here.

We have evidence of a huge ancient temple here.

We have also a small temple here,

which is a temple to Khonsou Tut.

We have another temple, a sanctuary I would say,

a sanctuary to Osiris here.

That's incredible! So where is this modern boat situated in this space?

We are just anchored here, sitting on top of the Temple of Amun.

With so many temples, Heracleion was clearly a place

of religious importance.

And sitting in a narrow waterway,

the team have uncovered something unique.

Do you want me to hold it while you do a check? Thank you.

Damien Robinson from Oxford University

is part of the excavation team.

And the compass being a critical bit of kit,

visibility not been fantastic.

Sacred artefacts have been found throughout this narrow stretch.

And alongside, something even more precious.

OK, so I'm going to go for a bit of a wander.

RESPIRATOR NOISE

Lying on the sea bed, still perfectly preserved,

is an exquisite vessel.

Long and sleek, it is carefully crafted.

It's made of sycamore, a high-quality wood,

and surrounded by ritual objects.

We could say that the ship sank

somewhere in the late-4th century BC.

So this is giving us a nice snapshot

of the things that are happening in Heracleion at this time.

The shape of the boat and the quality of the wood

suggest that this is something startling, a sacred barge.

There are images of these ceremonial vessels throughout Egypt,

but to find the real boat is incredibly rare.

This is the only ritual barge from this period ever to be uncovered.

It's a spectacular find.

Ancient writings describe an important Egyptian ceremony

celebrating the resurrection of the god Osiris.

Now seen for the first time,

this could be one of the very barges that led that procession.

And the fact that we've found a ship in an archaeological context

gives us much more understanding of what the vessel looked like and how it was built.

But, importantly, it's also the artefacts that are associated with this boat.

And all around the vessel, you find individual groups of ritual offerings.

And these are things that have been given by individuals,

people like you and me, who care about their religion

and who are offering up goods to the gods.

And for me that's what's really incredibly fascinating about this ship.

They've been excavating in the area around it

and this is one of the places

where ritual deposits are placed within...the water.

Here we can see one of my colleagues excavating.

He's carefully cutting into the clay

to gently remove the different layers of clay

to reveal the artefacts beneath.

So, as we can see, the excavation of what looks to me

like one of those small offering-type plates.

The simple bowl reveals one individual's act of worship

made on this very spot over 2,000 years ago.

Offerings would perhaps have been put on the bowl

and then slid gently into the water.

It's craftily made, carved out of stone.

So this is an example of everyday ritual,

a thing that the people of Heracleion would have done,

but it's really a beautiful piece.

Other finds brought up from the deep

show what kinds of offerings these individuals would have made.

Now in this spot there's a lot of bones. Oh, you've got...a tooth.

A burnt tooth by the looks of it.

Do you think these are burnt? Or it could be that it's taken...

because when it's in this deeper level, in the anaerobic level, the soil becomes quite dark.

OK. I'm sure that's what you're experiencing when you're excavating,

so sometimes they get discoloured by the context. So...

But that looks burnt.

Food may have been burnt, sacrificed,

then slipped into the waters of the sacred River Nile

on offering plates like this one.

Look at that. It's absolutely being grown over. Indeed.

Now, this is on a clay layer

with...these bone-like elements closely nearby.

Yeah.

And alongside the humble offerings, preserved for millennia,

are objects of extraordinary wealth.

Rich and poor alike offering their gifts to the gods.

'The finds in this remarkable city

'are giving us a unique insight into Egyptian religious practice.'

So it's over here? Yes.

'And here at the excavations laboratory in Alexandria

'are further clues to the importance of Heracleion

'in Egypt's sacred life.'

Ladles. Bronzes ladles with...

the end in the form of a duck. Yes.

An extraordinary number of these ladles, 70 in all,

have been found lying on the sea bed close to the temple.

In Heracleion, we found more of those ladles

than all ladles that were found in Egypt.

In all sites of Egypt.

It's overwhelming. It is. OK, thank you.

These are important ritual implements

used by the priest to purify offerings,

ladling water from the sacred River Nile.

And the finds include an astonishing array of rarely seen votive objects

given as a prayer to the gods.

Those are lead models of the barge of Osiris.

I've never actually seen votive boats, but I've seen images of them.

Images. And here we have them. Yeah.

And you can see this barge here. Oh, yes! You see the papyrus.

It represents a barge made of papyrus. You can see the striations.

And there was a throne here, there was a steering house here.

So you can steer. And here this part. So, sorry,

you're saying that they're deliberately destroying them?

Absolutely, to make offerings to the gods.

These boats were beautifully crafted,

but they, just like the animal bones, were sacrificed.

Who was making the offerings? Who was depositing these objects?

Obviously, the big objects were offerings from the priest. Right.

The inhabitants of the city, they were making small offerings.

Votive objects are the physical embodiments of prayers...

Miniature ways.

..their form representing the content of the prayer or the person who made it.

A small votive anchor. An anchor! A nice one.

This ancient anchor could be the prayer of a sailor.

A small elephant, to the god.

And this beautiful elephant the offering of a soldier.

Yes, Ptolemies had a big reliance upon elephants for their warfare.

So strange. Yes.

As well as the humble objects left by workers,

sailors and now soldiers,

there are incredibly fine pieces

fashioned at great cost by expert craftsmen.

And here, one of the most extraordinary pieces

of the entire collection.

One of the masterpiece of Heracleion.

Oh! It's a pharaoh. Stunning!

With the blue crown, which was the crown of the pharaoh fighting.

Yes. Defending Egypt.

Look at the detail!

This exquisite figure is over 2,500 years old

and the supreme quality suggests

it could only have come from one person, the pharaoh himself.

A masterpiece... It is indeed. ..of statuary, of Egyptian statuary.

So many of these objects are just of the top quality.

Such an object of that quality

would only be a gift from pharaoh to the temple.

Absolutely stunning!

Do you have favourite objects? Are we allowed favourite objects?

Is this...? I don't think we're allowed favourite projects,

but I have to say that this is one of my favourite objects.

An exquisite piece. Hmm.

These spectacular finds reveal Heracleion

as an important sacred centre.

But that's not all it was.

Could Heracleion have been significant

for more than just its temples?

So what's this large stone at the end here?

It looks like it's... This is a marble stone.

Among the religious finds at the lab

is one that hints at another very different role.

You can see an inscription on it. Oh, yes.

It's a beautiful Greek inscription.

And it's a text about a young man of 18 years

who died in...at the war.

And was buried in Heracleion.

The tombstone reads, "Here lies Lucos, son of Luciscos,

"he lived in the city of Pryim, the land of his father.

"He trembles not in the face of the phalanx,

"but under the blows of the enemy, he found death on the battlefield."

So this was found in an Egyptian city

right next to a pharaonic temple

and yet it's the tombstone to a Greek soldier.

Heracleion sat at the mouth of the River Nile,

making it a vital entry point into Egypt

and a place of huge strategic importance.

During the period of Heracleion's life, Egypt was invaded by Persia,

conquered by Alexander the Great

and suffered various internal power struggles.

But the most revealing finds are not weapons or spears,

but something much smaller.

Hey there. Hi, Marie. So what have you been working on today?

These are finds that have just come up? Yes, they are almost fresh from the water.

Marie Mon, the site's chief conservator,

is working on one of the hundreds of Greek coins discovered here.

Which is actually a Greek...

Is that a whole coin or is it...?

It's a little damaged. Yes, exactly. Can you see here? Yes, you can.

Big eyes of the owl. Yeah, big eyes.

Yeah. And all of the...feathers.

And this is not just any Greek coin, but one from Athens.

It's harder to see, but you've got the head of Athena with her hair.

'At this time, Egypt didn't have its own currency,

'trade and taxes were simply taken in goods.'

Head. And here you've got some Greek letters. Yes, exactly.

'So these coins were used to pay Greeks coming in from Athens.

'Soldiers brought into Heracleion to defend Egypt.'

So this kind of currency was probably made in Egypt

to pay for Greek mercenaries.

I love the idea of these things being minted

specifically for paying the mercenaries.

It reinforces the idea that there's a military presence here

and there are people who are being paid specifically to protect the site.

'Our Lucos could have been one of these soldiers.

'And the money that paid him

'may well have been made here in Heracleion itself.'

There seems to be coins everywhere.

Marie was showing me one that potentially was made here.

Oh, yes, we have two type of coins.

One we are sure has been minted here and the other one we suspect.

The one we are sure of is because we found

a lead weight with a negative imprint of that coin,

showing that they were minting it... On the spot. ..on the spot.

This stamp could have been used

to mint the mercenaries pieces of silver...

..creating hard currency accepted all over the Ancient World.

Heracleion did not merely sit on this vital gateway into Egypt,

but helped defend it.

The excavations here are bringing this forgotten city to life.

Heracleion was an important, bustling place,

thronged with soldiers, sailors and religious devotees,

but this spectacular site still has more to reveal.

The other thing that's really amazing about Heracleion

is it has not one, two, three...but 64 shipwrecks!

This is an incredible number of shipwrecks to find in one site,

particularly at such an early period.

In the Mediterranean, you have a huge number of sites

from the Roman period, but never so many from the earlier period and never so many in one site.

So this gives us the possibility to explore different types of ships,

boats that were carrying cargoes,

those that were lightering goods from the larger ships to the shore.

The vessels that were carrying trade goods upriver, up the Nile into the delta.

And at the same time, the different construction of the vessels

gives us an insight into the technology and technology is obviously an insight into people,

into maritime communities and into the life of the city of Heracleion.

Among the boats wrecked over hundreds of years

is one that is particularly significant.

This is the very front of our ship.

This boat is much, much larger than the ceremonial barge we saw earlier,

a massive 28m in length.

The planks themselves

are made out of a very local wood.

This is called acacia, it's a perfect shipbuilding material.

Herodotus described a type of river boat called a baris on his visit to Egypt

and we think this is more or less what we've got here.

These craft have never been seen before.

Perfectly designed for this region of the Nile,

baris were working boats, cargo boats.

It is a very substantially built ship. Yes, indeed.

But in terms of what it could be used for,

it's perfectly adapted for the environment.

So it's got a flat bottom, and it's probably a cargo boat.

I mean, that's sort of... Or people? It's wide and long.

Do you think it could've carried...

Presumably, when you've got this landscape of islands and channels

you need some way of moving around...

You do, absolutely.

..between the temple and your workshop, or whatever it is.

There's a fabulous Rameside papyrus

that talks about a temple fleet,

and the fleet sail around the delta

and they pick up tithes

from various properties that the temple owns.

Collecting the taxes. They do.

So I think this could well be involved

in either trans-shipping goods from the port to down the river...

This boat reveals another face of Heracleion -

a working port with fleets of cargo boats.

And below the surface,

there is evidence that the trade wasn't simply local.

There are a multitude of anchors littered across the site.

This is from a seagoing vessel -

at the top is a rope hole

and, at the bottom, holes for wooden spikes that would grip

into the sea bed.

Then there are the objects from Persia and Phoenicia,

cargoes from Cyprus.

It seems Heracleion was no small local port,

but an international one.

And then something spectacular...

A stone covered in hieroglyphs.

This pristine black granite stele

stands over two metres high

and it is full of information.

'A stele is a carved public decree

'and this one was found buried in the heart of the city.'

And the name of our city.

Heracleion. Heracleion.

This beautiful block is older than the Rosetta Stone...

..and has survived for over 2,000 years, completely intact.

It was commissioned by the pharaoh Nectanebo I,

and you see him here

presenting gifts to the goddess Neith...

and, on the right-hand side,

the date of its commission -

the first year of the reign of Nectanebo,

which is essentially 380BC.

'It looks like a religious monument,

'but it has another purpose - taxation.'

Here you see the amount of tax that was being levied -

10% -

on materials such as gold

and silver

and timber and worked wood.

So Heracleion was a major port,

charged with collecting customs duties on imports.

All coming in from the sea of the Greeks -

imports from the Mediterranean.

Towards the end of the stele

we have a specific reference to the port of Heracleion,

located, as it was, at the mouth

of the sea

of the Greeks - again referencing the Mediterranean.

These are the symbols for the foreign boats

arriving into the port.

And here we have the section of the stele

that references the port of Heracleion -

Ta Hone of Sais.

Thonis, the Egyptian term for Heracleion.

'But there is something else incredible about this stele.'

The stele that was found at Heracleion was not the only one.

There was a second stele

that was found 100 years earlier

at the site of Naukratis.

Naukratis was the great Egyptian centre of trade,

where are all goods from Greece

and the Mediterranean passed through.

It's one of the most important sites in Egypt.

The identical steles tell us something remarkable -

the forgotten Heracleion was the sister port -

the equal - of this renowned centre of trade.

Essentially, Heracleion and Naukratis,

this great Greek emporium, worked in conjunction with each other,

feeding the goods of trade through to the capital at Sais.

Our city, the gateway for international trade into Egypt,

was more than a legendary port,

it was a vital one.

Submerged and forgotten for millennia,

Heracleion is revealed as a wealthy city of scale,

with religious, strategic and commercial importance.

And then Franck found something breathtaking.

Right beside the temple, lying on the sea bed,

Franck found the head of a colossal statue.

And not just one -

head,

torso,

legs -

three great statues were assembled.

One, Hapi, the god of the Nile floods.

The others, huge stone images of the pharaoh and his queen,

each over five metres tall.

They were commissioned by the pharaoh himself,

carved inland and then transported

at vast expense to Heracleion's temple.

But there's something very unusual and significant

about the way this pharaoh is depicted.

Very curiously, he was represented as leaving the temple.

Oh, that's interesting.

Having in his right fist... er, what we call the "mekes"...

This was an object that contained the inventory of everything

existing on the land and in the sky,

given to the pharaoh by the gods,

it conferred on them the divine right to rule.

And that inventory he just received from the supreme god,

of the Egyptian Amun,

and by receiving this,

he was becoming the master of the universe.

So it's really this connection between the religious power base,

reinforcing his power, which then he's taking back

to his capital or back to the rest of...

He was the ruler of the universe, as a matter of fact.

He was the master of it.

And another find suggests that the pharaohs received

that right to rule right here at Heracleion.

Less dramatic than the statues, but more significant,

is this stone box.

This is the "Naus",

the sacred centre of the temple which housed the god.

Inscribed on this holy stone

is the description of specific dynastic rights -

rights that each pharaoh had to perform

to legitimise his power.

The pharaoh had to come into that temple

to receive from the supreme god Amun the title of their power.

And when they were coming in Heracleion,

we have written evidence

that there was a special palace to receive them.

So Heracleion was not just an important Egyptian city,

it was the very city where new pharaohs came to receive

the receive the divine to rule,

and legitimise their kingship.

To understand just how important that was,

we need to travel to the place

where these rights first came to prominence.

Over 800km south of Heracleion

is the site of the mighty ancient temple of Karnak.

This was the centre of power for the kings of Egypt

before the power base shifted north to the delta.

The most incredible thing is just the scale of it.

Yeah, and you feel that the moment you start walking in.

It's just overwhelming.

Karnak was a precursor to Heracleion,

playing the same role in empowering kings,

gifting their right to rule from the god Amun.

Elizabeth Frood has been working here for over eight years.

Of course, Amun was the significant deity in Heracleion,

so can you just tell me a bit about the role he played here?

Sure, he was a prominent early god,

but he only really becomes linked to kingship,

and the site of Karnak,

at the beginning of the new kingdom again.

And he is constantly and consistently bound up

with ideas of kingship,

and what it is to be king and how to renew royal power.

All around us on the columns here,

are figures of Amun with the king.

This is Amun on the left.

What's most characteristic,

and what communicates his identity most clearly, is the crown.

It has the double-plumed crown.

All the scenes showing human figures show the king before Amun,

offering to him,

performing rituals before him...

So anyone who entered an Egyptian temple

would have been bombarded with images of kingship.

He gains his legitimacy

through that intimate, ritualised relationship with the gods.

Just like in Heracleion,

we see that an Egyptian temple wasn't simply a sacred space,

it was a place that communicated and legitimised

the power of the state.

What I want to know is who would be looking at these inscriptions,

who were the people meant to be awed by the power of the king?

Liz has an ingenious way to find out -

graffiti.

I mean, I think of graffiti as, you know,

when you scratch your name randomly on something.

Is that the sort of graffiti we're talking about?

We definitely have some of that.

We've lots of scratches and scribbles of scribes

and other members of the temple staff

scrawling their names and title on the walls of the temple.

And they also draw little pictures, as well.

Let's have a look at them. Let's have a quick nosy in here.

This is amazing, isn't it? Yeah.

And this is another member of the temple staff.

His name Nebuneb is inscribed here.

And he is an overseer of...bakers,

or...something to do with baking -

the title is quite difficult to read.

Over 3,000 years ago,

an Egyptian worker sat here

and scrawled this picture.

Here we have a picture of Amun, a form of Amun,

Oh, wow, yes... You can see the plumes.

You tend to think about these sorts of workers

as being quite invisible. Yes, exactly.

Yeah, yeah, but through graffiti they become visible to us.

We will never know why someone carved this here,

but he knew.

And it gives you that feeling of a connection

with one individual in the past,

which is really hard to get sometimes.

Absolutely.

This graffiti is giving me a real sense of the ordinary people

who spend their days in and around this temple.

And the range of jobs they did is encapsulated in this one grand inscription.

Here we have an inscription of the high priest of Amun,

whose name is Roma, or Rui.

And in this text he addresses

some of the people that were working over here.

He's promising them a new building,

and he talks about greeting the brewers and the bakers

and the confectioners

that were all busy in this area producing offerings for the temple.

And these were the people and the priests, the scribes,

the bakers and confectioners

who the pharaoh was speaking to

when he declared his relationship

with Amun and his right to rule Egypt.

So what we're seeing here at Karnak

really makes that connection

between ritual, religion and royalty.

And it makes me reflect on how much that continuity

can be mapped out in Heracleion.

800km and 1,000 years apart,

and yet so much is still the same.

Amun is still the deity that needs to bestow royal power,

and Heracleion's colossi declare that power,

just as the iconography does here in Karnak.

For Egypt's final pharaohs it was not this mighty temple

that played the pivotal role,

but Heracleion's.

And that made Heracleion one of the most important cities in all Egypt.

What we've discovered about this once forgotten city is astounding.

It was a huge city,

a sacred centre

and the gatepost of Egypt

where soldiers, ships and trade flowed,

and even pharaohs gained their power.

The reality of the city is far more amazing than the myth.

Why then did it disappear without being missed?

How did this great place come to be forgotten?

Our discoveries so far have given us a clear understanding

of the role of Heracleion.

However, what we still don't understand

is what happened to Heracleion.

Why and how did it disappear?

And these are the bits of the puzzle that we have still got to

fit together.

There are several theories -

was it destroyed in an earthquake or a tsunami,

covered by a massive Nile flood...

..or just abandoned as it sank slowly into the sea.

Heracleion was a city of low-lying islands and channels,

at the mouth of this great river,

and as such was subject to flooding.

Before the early 1900s,

when my great-great-grandfather helped build the Aswan Dam,

the river would regularly inundate the land,

turning roads into rivers and villages into islands.

The Nile was the great bringer of life,

flooding the land with fresh water and fertile silts.

But it could also be incredibly destructive.

'I've come here to Rhoda Island in Cairo

'to understand when the Nile was at its most dangerous.'

It was really important that the Egyptians understood

the position of the Nile over its annual cycle,

and here we can see an example of

what was essentially a measuring gauge.

It was called a Nilometer.

It gave the Egyptians an understanding of

the point, the level of the Nile over the course of the year.

It was so important to understand the position of the Nile

that over time, these Nilometers were improved,

they were made more sophisticated.

So, this was most definitely in at the sophisticated end of

the Nilometer market.

Here you can see one of the three openings for the Nile rivers

to enter, and for the majority of the year, this area

would have been submerged, so I'd be underwater, effectively.

This huge column is essentially the Nilometer,

and each of the different stages is marked off in cubits,

giving an indication of the rising level of the Nile

as it extended over the course of the year.

'Priests would know exactly what height would lead to prosperity,

'to fertile fields and large harvests...

'..and what would lead to flooding and famine.'

As you work your way up the column,

you go up to various critical stages.

'Here, 12 cubits would mean hunger.

'14 cubits, happiness.

'But 16 cubits would mean abundance, rejoicing, festivities.

'Climb even higher, though, and the rejoicing would stop.'

If the flood levels rose above the 16 cubit mark,

then we were looking towards devastation across the country.

'Priests didn't just measure the changing level of the Nile,

'they recorded it, and many of these records still exist.'

The data that I'm looking at here is a detailed record of the Nile floods

from around 600 AD that was recorded here at the Rhoda Island Nilometer.

And here we can see particularly high episodes of flooding,

sort of mega-floods, as you were.

'These mega-floods happened in the 7th and 8th centuries AD,

'but we know that these did not destroy Heracleion,

'because by the time these monster floods hit,

'Heracleion wasn't even located on the Nile anymore.'

As the Nile River crosses the Delta towards the Mediterranean Sea,

it splits into a number of smaller branches.

In ancient times there were seven branches,

the westernmost of which was called the Canopic Branch,

and at the silty mouth of the Canopic Branch,

the ancient site of Heracleion was located.

'I've come to meet geologist Clement Flaux,

'an expert in this region and on the Canopic Branch in particular,

'to find out how Heracleion's river disappeared.'

Clement, we're here on the Rosetta Branch, erm,

which, I guess, would have been pretty similar to

how the Canopic Branch was in antiquity?

Yes, it does. This is where we are, just south of Rosetta. Uh-huh.

And this is where was the Canopic Branch here.

OK. The Canopic Branch was in the low lying deltaic

sedimentary context, with this kind of, er, humid vegetation,

which lie in the waters.

'Over time, silts deposited by the Nile built up,

'clogging the channel

'and reducing the Canopic Branch to a muddy stream.'

Do we have a sort of, a date at which we are fairly sure

that the Canopic Branch was defunct?

We have to distinguish between the mouth,

which was the first to be silted up, probably mainly because of

the Alexandria Canal, which, south of the mouth,

it diverts waters which used to reach the mouth. Ah-ha, OK.

So the flow decline at the mouth.

Yeah. Oh, so you think this is

as much to do with the sort of human action

as it was to do with the natural silting of the Canopic Branch? Yeah.

Do we have any idea exactly

when the Canopic Branch was completely silted? Not exactly.

Because it was a really very gradual, er, process, so we know that

around the 5-6th century AD the mouth does not exist anymore.

So the mouth seems to have disappeared at this time,

5-6th century AD.

'That was 200 years before the recorded mega-floods.

'When they happened, Heracleion was largely cut off from the river.'

It's clear from what Clement says that the idea of a big Nile flood

is not the primary reason why Heracleion vanished.

The timing just doesn't add up.

Essentially, by the time of the mega-floods,

the mouth of the Canopic Branch had already silted up.

'We've discovered that the Nile floods

'are not what made Heracleion sink.

'But the movement of the river did, in a very different way,

'play a part in the demise of this great city.'

'Its strategic and commercial roles were intimately bound up

'with its port.

'Once the mouth of the Canopic Branch silted, its port was defunct.

'But even before this process was complete, Heracleion's commercial

'power base was being usurped by the great new port of Alexandria...

'..founded by Alexander The Great in 331 BC.'

Alexander built his harbour here

because there was a solid limestone ridge that ran along this coastline.

That created a solid platform for the harbour.

'As Alexandria's port grew,

'Heracleion's diminished.

'So even before the city slid beneath the waves,

'much of its importance and power

'was taken over by Egypt's new capital.

'That might account for why there's no record of it sinking.

'But it doesn't explain how

'Heracleion vanished beneath the waves.

'If flood waters didn't drown Heracleion,

'maybe some other natural catastrophe was to blame.

'Franck has carried out a geophysical survey of the site

'and uncovered something remarkable -

'a ship graveyard.'

So you've got...

..the main harbour of the city of Heracleion.

In the middle of the harbour,

there are six, seven, eight shipwrecks,

which makes you think, "Well, why are they here?

"How did they get here?

"Are they a product of a simultaneous event

"or did this happen over a period of time?"

If it was a simultaneous event

then that equates to something fairly catastrophic.

'At first glance this looks like a tsunami.

'But Damien has uncovered something rather unusual about these wrecks.'

'And here is our excavation.

'What we can see here, this long, quite thick stake,

'it seems to be going directly down into the planking in this direction.

'One of our hypotheses at the moment is this is essentially a stake

'that has been used to try and pin the ship into position.

'This ship wasn't wrecked by a natural event

'but deliberately scuttled and carefully positioned.'

'This section is particularly interesting

'because what we can see here is the covering of stones which was

'put over the top of the wreck in order to secure it to the floor

'and make sure that it stayed down.

'Lots of the ships in this graveyard also had these stakes

'around them as well, and this is how all of the ships are

'placed exactly where the Egyptians wanted them.'

'This is truly unusual.

'If boats are abandoned, they are generally just left,

'not deliberately placed and fixed into position.

'It would appear that the residents of Heracleion

'were creating some sort of structure.'

I've been standing waiting patiently for you here since you left.

Staking boats on the bottom of a harbour is not normal practice,

and I guess you have to think about why they were doing that.

That's one of the mysteries that we're trying to think about.

You know, obviously, you don't sink a ship...

No, it's not really, no. ..in the middle of a harbour.

Or you don't sink seven or eight ships in the middle of the harbour.

I know already that there's elements of silting that's happening,

particularly in the northern part of the site.

Do you think it's something connected with that?

I think it could be. If the northern entrance has been silted up, er,

then you're looking at something like artificial creation of land.

We know that the northern part of the site seems to be, erm,

seems to be sinking slightly, so they might be creating a little island.

These boats could be an example of ancient land reclamation.

I really like the evidence that Damien's just presented to me -

this idea that the ships were deliberately sunk

on the base of the main harbour of Heracleion.

And I guess it's not so unusual in the ancient world,

but it's particularly uncommon in such an early period.

And Damien suspects the reason they needed to create more land

was because, at the time these ships were scuttled,

parts of the site were subsiding.

Heracleion was sinking.

Elsewhere on the site, another ship adds to the mystery.

So, Franck, I didn't realise that you had one vessel

that you're saying was catastrophically wrecked.

This is Shipwreck 61, south of the temple.

And...she was moored, most probably close to the temple,

and on that shipwreck, we can see a limestone block from the temple,

and even columns from the temple,

just...tumbled on it.

Columns from the temple have fallen and crushed the boat.

Some of the ceramics that we are finding on the temple,

which is perfectly dateable and in pristine condition, even intact.

We are finding the same layers

under...at the bottom of that shipwreck.

Ceramics trapped and crushed in the wreckage can be precisely dated.

That's just great, as archaeologists -

when you get something like that happening,

it's just the ticket with the date, isn't it? It is.

It's that specific point in time.

It's a kind of... Snapshot. ..image - snapshot - of an event

which has lasted a few seconds.

Meaning we could be looking at a scene

from Heracleion's very moment of collapse.

The ceramics and the other dating evidence

is pointing to what sort of time for this event?

We are at the very end of the 2nd century BC,

beginning of 1st century BC. Right.

The fact that the temple wall fell on top of this ship

that was moored alongside the temple

means that it happened in a single event

and in amongst the temple debris, on top of the ship,

we find pottery remains that give us an exact time

as to when the temple fell.

In the 2nd century BC,

the building central to Heracleion's remaining power

catastrophically collapsed.

But at this time,

no major earthquakes or tsunamis are recorded.

So what did destroy Heracleion?

The combination of subsidence and a sudden collapse

gives a vital clue.

Franck has worked with geologists to investigate the land

directly beneath the city.

Fire it up. All set.

Taking core samples, they have found that 2,000 years ago,

the earth here was a mixture of soft silts, sands and clays,

deposited during the annual floods.

To understand exactly what these results mean,

I've gone to meet sedimentologist Professor Jeff Peakall.

Hi. Hi. Beautiful landscape.

Oh, yes, absolutely fantastic. Definitely.

Being at the mouth of the estuary,

it's quite an interesting comparison, in many ways,

to the mouth of the Canopic branch upon which Heracleion was built.

So I'm interested in learning a bit more about this deltaic environment.

Yes. I mean, deltaic environments are the most active -

most peculiar, in many ways - environments that we have.

They literally build to a tipping point. Yeah.

At which point, sediment fails and it moves off.

Also, they're very liable

just to erosion and, obviously, to subsidence.

Deltas are far from static, stable environments

and it's not just the rivers and water channels

but the land itself.

This, sort of, dynamic tipping point, as you describe it -

I mean, is it something that happens instantly?

What are the triggers for this and how quickly can this happen?

It certainly would be an almost instantaneous effect.

Sediment can just fail under its own weight

but it's much more likely to be pushed by some large event,

so either a large river flood, or a tsunami,

or you can have an earthquake in here.

This can cause you to just move beyond that tipping point.

When the land fails, it can subside or erode.

But there is also another, stranger process -

a process that may well have occurred at Heracleion.

I know that the team have taken

a series of geological cores in the region.

I know that you've had a look at these.

Can you see anything specifically in that that maybe helps give us

a clue as to what happened, particularly at the site?

Yes - I mean, they're very strange to look at,

because normally, when you look at cores,

particularly modern ones, you expect to see a series of nice, flat,

horizontal layers through them

and that's because sediments are always deposited

almost horizontally... Yes. ..in the natural world.

But in the middle of these, you see some that are completely bent

and deformed within those

and this gives us a big clue,

because this is a sign of liquefaction,

where you change a solid into a liquid.

At some point, the land below Heracleion didn't simply sink -

it liquefied.

This is a simple but nonetheless very effective demonstration

of liquefaction -

it's just a tank that we've filled with sand and with water

and, at the moment, is a nice, stable environment.

But, as we've heard, deltas are inherently unstable environments.

And in order to demonstrate this,

I've brought a little temple for you...

Really? ..to place on top.

LAUGHING: That's great. Thanks so much.

So, here we are, temple in Heracleion,

based on solid ground, or what seemingly, at this point,

is solid ground.

Well, we could have a number of triggers that could transform

this solid into a liquid, but for our purposes here,

we're going to simulate a small earthquake,

using this.

All I'm going to do is actually tap this very gently

on the side of the tank.

Yeah. And we'll begin to see some changes.

Ah! You can already see that you're getting a very dramatic change.

You can see the water coming up to the surface

and you can see that our temple is beginning to move. Amazing!

And what's happening here is that our sand is, er...

is compacting and, as a consequence, it squeezes out water

and it locally turns into a liquid

and, as you can see, our temple base has sunk straight into this. Yeah.

'These soft muds and sands need only a minor force

'to trigger them to sink and spurt out liquid.'

It's quite interesting how just a small vibration,

a small movement, can actually make quite a dramatic impact.

Yes, that's it.

I mean, once you've got liquefaction, then you'll see that temples

and columns will start to tilt and tip and potentially collapse,

but also you could get larger-scale movement.

If you've got solid -

you could have solid on top of a layer that liquefies,

you've have solid on top of a liquid

and that can just literally slide off and slump,

so whole parts of a city, potentially, can sort of move

considerable distances during the time that this is a liquid.

'Buildings erected on unstable, muddy soils can collapse

'as if their foundations had been built on quicksand.'

So the demonstration that Geoff has just shown me

of the process of liquefaction is a really visual insight

into how this fairly vulnerable landscape,

at the mouth of the Canopic branch,

upon which Heracleion was built, could have changed so dramatically.

The same thing that occurred at Heracleion in the Second Century BC

occurred in New Zealand in 2011.

Land liquefaction devastated a modern city.

So imagine the impact in ancient times on towering temples -

structures with no foundations.

It didn't have to be a major tsunami,

it didn't have to be a huge earthquake -

it didn't necessarily have to be recorded by the ancient historians,

it could have been a minor event

but the impact of that event was devastating.

Heracleion sank, to be lost and forgotten for over 2,000 years.

In the end, the silts of the Nile, the so-called Bringer Of Life,

were too unreliable to build a city on.

No matter how great its power became,

Heracleion's reign could only ever be temporary.

Ironically, the silts of the Nile that destroyed Heracleion

are also the thing that have allowed its perfect preservation.

And, as a result, we are able to rebuild this city, piece by piece.

A city of temples.

A military garrison keeping the state safe from invasion.

A vast port, linking Egypt to the world.

And a royal city, vital for the continuation of pharaonic power.

Heracleion, sleeping and forgotten for thousands of years,

is now revealed - one of the most important cities in Egypt.