Original subtitles

Narrator: Hidden for centuries,

A strange mega structure Emerges from beneath the sea

And sand.

An ancient timber circle -- Seahenge.

I think it's An upside down tree.

It was huge, And it went down so far.

Narrator: lost beneath the waves For thousands of years,

This submerged wooden circle Conceals many

Prehistoric secrets.

Something peculiar Is going on here.

And could hold Clues that marked

The beginning of The bronze age.

Knight: this is a period Where we see

The first metal objects Being produced.

Society is getting very Technologically savvy

At this point.

Narrator: today, experts use Pioneering technology

And 3d scan analysis

To shed new light on who Builds this unique monument.

What dark rituals are Performed here?

What secrets does it share With the iconic stonehenge?

To solve these mysteries, We blow apart

This bronze age monument Piece by piece.

We investigate a second Submerged prehistoric circle,

Unearth ancient skeletons,

And digitally rebuild The lost mega structure

To uncover the truth behind This strange sunken wonder.

Holme beach,

A remote stretch of coast In eastern england.

Today, It is a peaceful haven,

But the discovery of A strange relic reveals

A dark macabre past

And could transform Our understanding

Of our prehistoric world.

One summer's day, Coastal sands shift

And reveal An ancient secret.

Hidden in the silt is A mysterious structure --

55 timber posts

Arranged in a wide circle.

They're made from tree trunks Split down

The middle and covered In strange markings.

And in the center of The circle,

Erupting from the sand

Sits a colossal, Strangely shaped object.

What is This peculiar structure?

♪♪

Maisie taylor Investigates the wood

Of this submerged edifice.

You had these quite stunted,

Obviously very damaged timbers In the circle.

Narrator: the Extraordinarily-shaped object at

The center of the circle Captures maisie's attention.

At first, it appears this Object is a huge tree branch,

But closer inspection turns This theory on its head.

Taylor: The more you looked at it,

The more you thought They're roots.

I think it's

On upside down tree.

Narrator: With the threat of the sea

Washing the newly exposed Structure away,

Maisie and an 11-strong team

Of archaeologists race to Excavate the site.

They dig 4 feet down Into the mud

To carefully extract Each timber.

They use heavy Lifting equipment

To finally remove The central tree.

Taylor: the most extraordinary Thing we found was it was huge,

And it went down so far.

Narrator: with the timber circle Safely extracted

And preserved In tanks of fresh water,

Experts can investigate clues To its age and origins.

When scientists examine The tree rings of

The wood, they discover it Dates back to 2049 b.C.

It means the structure Is 4,000 years old

And dates to the bronze age.

At this time,

Monumental circles of Different types

Stand proudly across The country.

The best surviving Is stonehenge,

Built 1,000 years earlier.

Used by prehistoric people For centuries,

This stone landmark is A monumental reminder of

Our ancestral past.

Originally in the center, Five archways stand in

A horseshoe shape,

Surrounded by two concentric Circles of rock.

With the layout of the timber Circle resembling britain's

Iconic stone circle,

Local press coined The name seahenge.

All that remains On the beach today is

A metal pole that marks The spot where it once stands.

What does the mysterious Structure look like

In its prime?

Maisie believes Measurements from

The excavation could Provide evidence.

If you start looking at Those depths below ground,

It gives you The height above ground.

Narrator: the timbers They discover at seahenge

Plunge 3 to 4 feet Into the sand.

Taylor: the rule of thumb Is that a third of

The wood needs to be in The ground to make it stable.

Narrator: maisie tests this Theory at a smaller scale

To calculate the original Height of the structure.

It really is quite stable,

So I think we can get on With our calculations

Assuming roughly a third Is underground.

Let's have a look.

Yeah, it's about a third.

Narrator: maisie's calculations Reveal the original timber

Circle is a staggering 10 feet tall.

Taylor: this amazing wall would Have been pretty impressive.

I'm 5-foot tall, So the timbers are

Going to be twice As tall as me.

Narrator: When they're unearthed,

The timbers are worn And weathered,

But in their prime,

The trunks tower Up to 10 feet high

And stand shoulder to shoulder To form a circular fence.

At the front,

A y-shaped post Creates a gap,

An entrance That gives access

To the tree stump In the center.

To close the circle, A final

Post stands in front of The entrance,

Which perfectly aligns with

The rising sun On the summer solstice.

What is the purpose Of seahenge?

This solar alignment is Similar to stonehenge, where

The heel stone aligns With the rising sun.

Each year on the solstice,

Ancient people host Sacred rituals here.

But the central stump in The heart of this circle

Is a clue that seahenge has A different purpose.

John collis is on a mission to Solve this mystery.

The tides At seahenge have swept

Away any loose evidence Around the circle,

But john spots A similarity with

Another prehistoric site 70 miles inland.

It's called wigber low,

A 16-yard stone circle Surrounded by colossal

Limestone blocks.

Its layout is similar To seahenge.

It offers A unique window into

The lost world Of the bronze age.

When john excavates the site,

He discovers multiple Fragments of bone and pottery

Dating back to the time Of seahenge.

Could human remains scattered Within the mounds of wigber low

Reveal the purpose Of these strange structures

And give us A rare insight into

The fascinating lives Of these ancient people?

Right away across the mound, We were picking up teeth,

Finger bones, toe bones,

But also very noticeably Absent were any traces of

The larger bones.

So immediately, We began to think

That something peculiar Is going on here.

Narrator: john suspects the Presence of small human bones,

But the lack of large ones, Could be a sign wigber low

Is used as a dark Prehistoric ritual called

Excarnation.

Collis: excarnation Is a burial rite.

When somebody dies, They are laid out,

Exposed to scavenging birds.

The flesh is removed,

And many of the Bones are left behind.

Narrator: excarnation is also Known as a sky burial.

Once complete, The large bones are

Removed and buried in a grave.

But traces of The ritual remain in

The form of tiny bones That fall from the body.

Collis: excarnation seems To be the most

Sensible interpretation.

Very small bones are simply Trickled down through

The mound, But larger bones,

One would expect, Are just missing.

Narrator: john's discovery of Pottery and small human bones

At wigber low prove people of The bronze age performed rituals

For their dead.

Is seahenge an excarnation Site like wigber low?

Collis: we know in other Societies that exposure of

The dead can be taking place In trees.

This is one interpretation for

The upturned tree trunk In seahenge.

Narrator: when someone dies,

The community carries their Body to the timber circle.

They lay the body out On the upturned stump,

Expose it to the elements,

And let the flesh decompose.

Visible for the surrounding Communities to see,

Scavenging animals move in To strip down the corpse.

Once the excarnation Is complete,

The remaining bones Are gathered to be

Buried elsewhere.

Maisie believes the inverted Tree trunk at seahenge

Is a clear sign of excarnation Taking place.

Taylor: The central tree

Is precisely the right shape And size to place

A -- what we call a crouched Body in the embryo position.

Narrator: The discovery of seahenge

Reveals that people of The bronze age celebrate

The dead in the form of Elaborate sky burials.

But what can another Mysterious object

Imprisoned beneath the sands

Reveal about this 4,000-year-old Burial rite?

Narrator: seahenge, An ancient sky burial site

Where scavenging birds eat The flesh of the dead

Unearthed from the sand After 4,000 years.

But just weeks after Its discovery,

Another mysterious Monument emerges.

Seahenge is not alone.

Just 300 feet east Of their first find,

Archaeologists uncover a series Of ancient flat timbers.

Now decayed, they once form A huge second circle.

Over 40 feet wide,

It covers an even bigger area Than seahenge.

On the inside,

Up to 60 smaller posts Mark out an inner circle.

Finally, In the very center,

A woven wicker fence surrounds Two logs lying side by side.

Could this second circle Mean seahenge is

Part of an even bigger ritual?

Today, the second timber Circle lies hidden

Beneath the sands,

But all is not lost.

Before it is Completely reburied,

Archaeologists take A sample from the monument.

Cathy tyers believes dating The wood can reveal.

If seahenge And the second timber circle

Are constructed at The same time.

To do this, she observes Ring patterns on

Wood that form over The lifespan of the tree,

A snapshot of The climate conditions

In which the tree grew.

The wide rings Are actually where

The tree was very happy That year.

It wasn't short of nutrients,

Whereas some of these rings in This sample are actually very,

Very narrow,

So it shows that the tree was Actually under stress.

So those wide and narrow rings That pattern through

Time is giving us some Information about the climate.

Narrator: cathy compares The ring patterns from

The second circle timber To those from seahenge.

If the ring patterns match, This is proof

Both circles are built At the same time.

Tyers: The black line was seahenge.

The red line is actually from

The other timber circle That was discovered.

And what we can see here is

That the ring pattern is Very similar.

We've got peaks And troughs -- so wide

And narrow rings In the same place.

And because that outermost Ring on

A lot of those timbers Is only partially formed,

What we can actually say is That they were

Felled in spring or very Early summer 2049 b.C.

Narrator: this evidence reveals The second timber circle is

Built within just a few months Of seahenge.

This could mean that both These monuments are

Part of a complex and Intricate burial practice.

Archaeologist maisie taylor Believes the two central beams

Of the second timber circle are

The key to understanding The role each monument plays in

This 4,000-year-old ritual.

Taylor: in the very center are Two huge logs.

They were about 6 feet apart And precisely aligned so that

The most logical and sensible Explanation is that a coffin

Would have sat on them, And this site

Was the final resting place

For somebody.

Narrator: maisie thinks That when the excarnation

Of the body At seahenge is complete,

The bones are placed into A coffin made from

A hollowed-out tree trunk.

The mourners then carry it 300 feet

In a ceremonial procession To the second circle.

Here they lay the coffin Across two central stumps

And bury it with earth,

Cementing the transition To the afterlife.

4,000 years ago,

The inhabitants Of this area build

Not one but two monumental Timber circles.

Here they host elaborate Ceremonies to

Commemorate the death Of their loved ones.

These practices are Not unique to seahenge.

At stonehenge, Cremated human remains

And hundreds of Skeletons are buried around

The outside of the circle.

But in holme beach, The bones remain

Inside the second Timber circle.

Are the people That build stonehenge

And seahenge related?

Could clues unearthed Two miles from seahenge

Reveal the answer?

Narrator: 4,000 years ago,

Two mysterious circles 300 feet apart

And twice the height Of a human

Are built with colossal tree Trunks at their center.

Archaeologists believe They are used

In complex burial rituals,

But who are the groundbreaking

Ancient engineers Behind these monuments?

David robertson is on A mission to track them down.

He heads To thornham village,

Just two miles from seahenge, To investigate.

Robertson: this location is Really interesting,

Because looking straight out There is where the sight of

Seahenge and the second Timber circle

At holme beach would Have bean.

Narrator: but this hilltop Overlooking seahenge

Is more than just A vantage point.

David thinks it could hold Clues to identifying

The builders of the seahenge Ritual complex.

Robertson: one of the reasons This site is so important

Is that we have Aerial photographs

By the raf that show Crop marks.

Narrator: distinct lines In the fields are

A clear sign that something Hides beneath the ground

And needs investigation.

When archaeologists Excavate the site,

They uncover the remains Of a fort

Dating back to the romans, And in the center,

They unearth dozens of Skeletons buried

In shallow graves.

But it's what they find Beneath the foundation,

Which most excites them --

Evidence of a much Older settlement.

They unearth eight fragments Of pottery

That date back To the early bronze age

And are delicately And distinctively decorated.

Can this pottery help identify The builders of seahenge?

David believes that the unique Style of pottery is

A direct link to a particular Group of highly skilled people.

It is the signature of The beaker people,

Named after their unique,

Bell-shaped drinking vessels Known as beakers,

But they are from Mainland europe.

What is their distinctive Pottery doing here?

Is it imported?

Or is it evidence the beaker People are in britain

And could be the builders Of seahenge?

Matt knight believes An ancient skeleton

Holds the key to unlocking This mystery.

Archaeologists excavated The grave of a young woman

Buried at sorisdale on The west coast of scotland,

And she was buried with a very Small, ornately-decorated pot.

The style of the pot Suggests to us

That she is one of The beaker people.

Narrator: radiocarbon dating of The skeleton shows

She dates back to 2470 b.C.,

400 years before Seahenge is built.

She is proof The beaker people are

In britain in time To build seahenge.

Is there more evidence They build it?

Matt believes the answer lies With the technology used

To fell the timber And construct

The magnificent wood circle.

Knight: this is a period Where we see

The first metal objects Being produced.

We start off with copper Daggers and copper axes

And over time, That transforms

And is alloyed with tin To make bronze styles

Of axes.

Narrator: By the time seahenge is built,

Bronze tools are Spreading across the country.

Matt believes the beaker People are responsible.

They come to britain for Copper and tin to make bronze.

Metal would have been a key Part of why people moved.

This is the first metal age Of britain.

Narrator: the beaker people Make their way across europe

And arrive in britain By 2500 b.C.

They are skilled metal workers

And bring their bronze-making Technology with them.

Here they mine And smelt british copper

And tin to make Their bronze.

This marks the beginning of The british bronze age.

They forge bronze tools that Are sharper

And stronger than any used In britain before.

Knight: this period where Bronze becomes adopted

Is around the time that seahenge Was being built,

And we can link all These different ideas

Relating to metal-working, Pottery, and monument building.

Narrator: the beaker people Introduce bronze technology

To britain and build Magnificent monuments.

They set about constructing

Seahenge and the second Timber circle,

And they travel inland To erect 20-ton sarsen boulders,

Adding a third circle to Britain's iconic stonehenge.

They add the finishing touches To the colossal

Avebury stone circle

And build thousands of Settlements across britain's

Rolling landscape.

How do the revolutionary, Bronze-wielding beaker people

Bring about such Dramatic change to britain?

Studying the dna of 400 european Skeletons from before

And after The beaker people arrive,

Matt discovers Something astonishing.

The dna was particularly Remarkable in showing this 90%

Turnover in genetic material Over the course of 1,000 years.

Narrator: incredibly, Within just 1,000 years

Of the first beaker people Arriving in britain,

They make up 90% Of the entire population.

Is this evidence that The beaker people

Violently overthrow The indigenous inhabitants

Of britain?

Matt believes The long transition period of

1,000 years shows a different, More surprising story.

We suspect that over The course of 1,000 years,

You get this integration of Communities, intermarriage of

People, and that slowly produces The genetic makeup.

Narrator: matt's research shows That these new people are not

A threat To the indigenous communities,

But instead are A welcome addition.

4,500 years ago, The beaker people migrate

To britain and mix with The indigenous people.

They integrate with them,

Forming a new british culture And build monuments to

Celebrate the dead.

Can their bronze tools tell us More secrets of seahenge?

What can discoveries On its timbers

Reveal about life In these prehistoric times?

Narrator: Seahenge is a mysterious

4,000-year-old structure found On the english coast.

Archaeologists discover It is built by

The migrants who bring Bronze to britain.

Can clues found at seahenge Reveal more

About these pioneering people And how they live?

When archaeologists extract The ancient timbers,

They make A remarkable discovery.

At the base, where the logs Are best preserved,

They find dozens of scars In the wood,

The marks of bronze tools,

Most likely the axes the Builders used to fell the trees.

Other timbers carry shaving Marks where branches

And twigs have been stripped -- These incredible

Ancient records etched into The wood reveal remarkable

Evidence about bronze age People and how they live.

Archaeologist And ancient wood specialist

Maisie taylor is

Conducting a forensic analysis Of the seahenge timbers.

To examine the axe markings

In the microscopic details She needs,

Maisie uses ultra high Resolution 3d scans.

This point here, an axe has Completely bitten in and stuck,

And they've had to pull It out.

We've got the whole shape Of the axe

And the complete Width, as well.

That is the precise shape of The axe.

Narrator: but when maisie Inspects another seahenge

Timber, she discovers Different axe markings.

When we look at The axe marks on here,

They look quite different.

They're definitely Wider, flatter.

So whoever cut this down Was using a different axe.

Narrator: maisie believes that By studying the variation of

Axe marks on the timbers,

She can calculate the size of The workforce involved in

The construction of seahenge.

I've got a bronze-bladed tool.

One of things That isn't so clear

Is blemishes on The edge of the blade,

And so when the axe bites in,

It will leave the pattern Of the blemishes.

Narrator: the blemishes create A unique fingerprint for each

Axe used in the construction Of seahenge.

Maisie uses This information to count

The total number Of axes.

Taylor: there has to be at least 50 different axes,

And so you've got at least 50, 50 plus people just working on

The trees And the timbers.

Narrator: this realization Uproots historical

Assumptions about Bronze age communities.

Far from being Primitive tribes,

The builders of seahenge are, In fact, a highly organized

And skilled society.

Taylor: somebody has decided What they're going to build,

Rounded up the people who've Got the right skills,

And got them all working

And ending up with a carefully Worked-out structure.

Narrator: but with seahenge Surrounded by

Two miles of flat sands And dunes,

Where do the beaker People source the wood?

Analysis of the timbers reveal

Seahenge is built From solid oak.

Taylor: it's absolutely clear That the wood could not have

Been growing Immediately alongside

Where the monument was made, Because they're healthy young

Oak trees, And they don't grow in water,

And they certainly don't grow On the edge of the tide.

Narrator: The oak must come from inland.

How do they transport tons of Timber to this coastal site?

Maisie turns her attention To the 3d scans

Of the upturned Tree trunk.

You can see two holes Cut really

Quite precisely On either side.

Narrator: But close examination of

The holes reveals Something extraordinary.

There are still traces of Where the rope went through.

Narrator: and maisie suspects These holes

And rope markings could reveal

How they position This two-ton tree trunk.

Taylor: it was obvious there was Still rope in place.

Narrator: Scientific tests reveal

The rope is made From honeysuckle,

A plant commonly growing In woodland.

Honeysuckle grows By winding itself around

Anything it can get hold of, Including itself,

And they exploited that To make

Very strong rope.

Narrator: but how did The builders of seahenge move

A two-ton tree trunk using Just strands of honeysuckle?

Taylor: well, The rope, originally,

Would have Encircled the trunk.

Presumably when They were towing it,

The ropes trailed up, and they Were still attached through

The holes, proving

Once and for all that these Holes were used for towing.

Narrator: first, Workers cut down trees

And uproot one large oak stump.

They drill holes Into the stump

And attach ropes Made from honeysuckle.

Then they haul the timber Through the woodland

To where they build Their magnificent monument

For the dead.

Here they dig a hole And a circular trench so they

Can install the central altar And the timber fence around it.

But one mystery Remains unsolved.

Why bring all the materials To this site

Rather than building Near the woodland?

With the discovery Of over 1,000

Prehistoric circular Formations across

Britain's landscape,

Why are the seahenge circles The only ones found by the sea?

Narrator: 4,000 years ago,

Not long after stonehenge Is built, two more

Strange prehistoric monuments Rise up

On the english coastline --

Seahenge and a second Timber circle.

But why do The bronze age people

Build these monuments here On this remote beach?

David robertson believes The clues lie

In the sand around seahenge.

The sand that's in My hand at the moment,

That's the modern Beach deposit.

But these weren't here When seahenge

Was built In the bronze age.

Narrator: what does this beach Look like back then?

Not far away, There are sediments just

Like those that seahenge Was built within.

Narrator: 3 feet beneath the sand

Lies a completely Different sediment.

In parts of the beach,

This sediment is Visible today.

If I just scrape off a little Bit of the clays and silts,

Run them through my hand,

You can see how soft And sticky they are

All over my fingers.

And if I pick up Some of the sand

That's on the beach, Lays around,

You can see how different The two are.

Narrator: The ancient clays are formed

From very fine particles,

Unlike the larger grains of Modern beach sand.

We know from The seahenge excavations

And from work On the second circle

That both structures were built In the environment that -- that

Silts and the clays Were laid down in.

Narrator: both timber circles Are built in

These sticky gray clays And silts.

David surveys the coast to Look for a modern equivalent.

If he can find The matching soil,

It will reveal The original environment

The timber circles Are built in.

I'm just having A very gentle scrape

Around in these modern salt Marsh deposits.

Having a look At the color.

Having a look at The consistency,

Narrator: David compares the sediment

From this modern salt marsh to

The clay and silt samples From seahenge.

Although you can see The colors are

Slightly different,

The modern salt marsh sediment Is slightly darker,

There is a lot of similarity In consistency,

Both are silts and clays, Both are very, very sticky.

Narrator: from this sticky soil, David can deduce that

Seahenge is built In a salt marsh.

I believe this is just like

The environment in which The two circles

Were constructed.

Narrator: a surprising Discovery just yards from

Seahenge makes it possible To piece together

This ancient environment.

When archaeologists extract The timbers of seahenge,

They find an antler Buried in the peat

Dating to the same period As seahenge.

It comes from a red deer,

A clue this area Is not always a beach.

This unexpected discovery lets Scientists paint a clear

Picture of the prehistoric Landscape around seahenge.

In its prime,

The would circle sits in A grassy marshland

Teeming with life, Miles away from the sea.

Why is this landscape So different from today?

Robertson: At some point in the past,

Potentially in the iron age Or maybe later,

The sea engulfed this area.

Narrator: Over thousands of years,

The north sea Inundates the region,

Destroying the timber circles And burying them

Beneath the sand.

But how do the remnants Survive to be discovered?

As plants growing in The marshland die,

They decompose into a thick Layer of peat that builds up

Around seahenge.

When a protective sand dune Moves inland,

It exposes seahenge To the ocean.

Now the tide submerges Seahenge twice a day,

And its timber begins to decay.

But sealed in The water-logged peat,

The bases survive

To be discovered 4,000 years later.

Robertson: without The peat beds, seahenge

And the second circle wouldn't Have survived.

Narrator: Over 4,000 years,

The sea, peat, and environment All work in perfect harmony

To preserve the two timber Circles for us today.

Why do the people Choose this remote,

Seemingly uninhabitable,

Marshy location For their great monument?

Can an ancient settlement 40 miles away reveal clues?

Narrator: on the eastern coast Of england,

Investigations at seahenge Reveal a tribe of people

From europe

Who bring bronze to britain.

Why do they build Their monumental timber circle

In this netherworld Between land and sea?

Francis pryor believes A bronze age settlement

Discovered in A vast marshy basin

40 miles from seahenge Could hold clues.

The fen base is very Low-lying landing.

It covers about A million acres,

Which used to flood from The sea.

Narrator: It's identical to the original

Environment Around seahenge.

Here, francis discovers A surprising structure

Beneath the mud.

This, then, is The bronze age causeway,

Constructed from about 1300 b.C.

Narrator: 700 years after seahenge,

People here construct This colossal wooden

Causeway on the edge of The fen basin in an area

Known today as flag fen.

It stretches almost a mile Through dense marshland

Connecting two Bronze age settlements.

Pryor: we estimate That there are about

60,000 timbers In the flag fen causeway,

So it was a major Engineering undertaking.

Narrator: This community uses

The same building Techniques for their causeway

As the builders of The sacred timber circles,

Working in great teams to Build the enormous structures.

But unlike seahenge On the coast,

This sheltered basin is Littered with hundreds of

Extra clues.

Francis's team Finds hundreds

Of bronze artifacts Alongside the causeway.

The causeway, Like a modern road,

Was used for carrying goods.

We actually found a wheel, We found pieces of axles,

So society is getting very Technologically savvy

At this point.

Narrator: discoveries here Reveal the huge efforts

Bronze age people make To settle marshy wetlands.

But why are they So determined

To live and bury Their dead here?

Francis believes the people Are fascinated by water.

Pryor: every day, We look in the mirror,

But in the bronze age, People didn't have mirrors,

So they didn't know what Their faces looked like,

Unless they look down Into the water,

But you pass below the water, And you drown.

It's the world of death, It's the world of the ancestors.

Narrator: just like the people At flag fen,

The people of seahenge are Drawn to water.

What can this ancient Fascination tell us

About seahenge?

You get a similar feeling At seahenge,

Where the tree is placed Upside down,

And it's going down into

The world below the surface.

They also had a vision of

The afterlife being below The ground, below water.

Narrator: francis's Investigations reveal

That people of the bronze age

Have a deep spiritual Connection with the afterlife,

And the monuments they build Form a direct

Link from their world To the spiritual world.

Pryor: and that's why sites Like flag fen

And seahenge were so Important to people,

Because those sites Gave structure

And meaning to their lives.

Narrator: 4,500 years ago, A sophisticated people

Migrate to britain

And kickstart The british bronze age.

They build Two colossal timber circles

To commemorate Their dead.

Over time, these people Thrive in britain.

These unique timber circles Finally reveal secrets that

Revolutionize Our understanding

Of the bronze age and The people who make it possible.

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