Original subtitles

[narrator] A team of truthseekers is on a mission.

Scientists. Historians. Archaeologists.

All on the trail of history's enigmas.

Searching for the truth

behind the greatest mysteries

known to humanity.

The Great Pyramid is the largest

of three vast monuments at Giza.

But who built it?

How did they build it, and why?

It remains standing after 4,500 years,

but could there still be ancient treasures

and secret chambers hidden within its stones?

In London, our team assemble.

Our four truthseekers combine decades of experience

in different fields.

But they all have one goal.

To apply their knowledge, and reveal the truth.

There are mysteries and then there are mysteries.

I have always loved uncovering the secrets of the past.

We need to go back and unpick the untruths from the truths.

Age-old problems that we've been asking ourselves

for over 100 years, really, can now be solved.

[narrator] They'll follow the clues left behind.

Unravel the secrets of the past.

Separate fact from fiction.

And together, they'll uncover the truth

behind the greatest mysteries ever.

[epic music playing]

[Fern] I love the Great Pyramid

because it is this intense mystery.

We've all grown up seeing it.

On stamps, in films, in documentaries...

[Tony] The Great Pyramid.

Its sheer scale,

its fantastic age

at four and a half thousand years,

and the fact that it's the last

of the seven great wonders of the classical world

that's still with us today.

It's an enduring symbol of the past.

It connects us to this past that we all share.

[Karen] Pyramids are one of those constructs

that we see almost universally across cultures,

and it represents kind of a unique crux

of, specialized knowledge of technology, economy,

aesthetics, and cosmology.

And when you think "pyramid," well, immediately you think

the Mack Daddy, the Great Pyramid of Giza.

[narrator] The Great Pyramid is the largest

of three vast monuments at Giza.

It stands with the pyramids of Chephren and Menkaure,

all built within 100 years of each other.

It is more than four and a half thousand years old.

It was built in a time when Egypt was a mighty power.

Ruled by a king, a pharaoh named Khufu,

Egypt's empire stretched around the Mediterranean

from modern Libya in the west

into what is now Turkey in the north.

But this golden age did not last forever.

Other powers rose.

The Egyptian Empire crumbled.

And time buried the secrets of the pharaohs in the sand.

The mystery of the Great Pyramid hinges on three big questions.

Who built it, how did they build it, and why?

Theories have created mysteries,

and I can't wait to start investigating.

[narrator] Anthropologist Karen Bellinger

has been taking a closer look at the builders

of the Great Pyramid.

I'm Dr. Karen Bellinger, and I'm an anthropologist.

I've traveled the world exploring sites

from prehistory to the modern day

in search of what it means to be human.

Typically, when people think about the Great Pyramid,

they think about Khufu, the pharaoh who built it,

and who was buried there.

But honestly, what excites me most as an anthropologist

is getting behind that façade.

[narrator] The Great Pyramid was built on a rocky plateau

on the west bank of the Nile River

in the 25th century BC.

At its base, the Great Pyramid is a square

roughly 230 meters by 230 meters.

The four sides rise together to a stubby peak

138 meters above the surrounding sands.

The Great Pyramid today is incredibly impressive.

It's a mountain of rough-hewn limestone

rising up out of the desert.

But what's really incredible is that, in ancient times,

it was all the more spectacular.

The outer surface of it was clad

with a glittering white Torah limestone

that would have shone under the desert sun.

The Great Pyramid was the largest thing

anybody had ever seen in terms of human-built structures.

And what's even more amazing

is that it remained the tallest structure

for thousands of years.

It wasn't surpassed until the high Middle Ages,

the 13th century,

when the age of cathedrals dawned in Europe.

[narrator] The Great Pyramid consists of around

2.3 million blocks of stone,

some weighing as much as 80 tons.

[Karen] I think it would be hard to overstate the impact

the Great Pyramid would have had

on any who beheld it in ancient times.

You know, in 2500 BC,

there's this colossus rising out of the desert.

There was nothing like it visible anywhere.

[narrator] Its sheer size has created doubt in some minds.

How was it even possible for the ancient Egyptians

to build such a monument?

We've been trying to understand who built the pyramids

ever since the Western world fell in love with them

in the 18th century.

And there's always been a degree of cynicism in some quarters.

That this was just an impossible task

for a civilization that existed that long ago.

Baseless claims that the ancient Egyptians

could not have built the pyramid

falls right in line with other theories

put forth about indigenous black

and other people of color

whose amazing achievements are denigrated.

But, you know, you rarely see people suggesting that

the ancient Greeks or Romans didn't build

all of the monuments that are attributed to them.

[narrator] For centuries, it was assumed

that slaves built the Great Pyramid,

tens of thousands of them.

The ancient Greek historian Herodotus

journeyed to Egypt in the 5th century BC.

He wrote the wonders he saw there

and the stories that he heard.

He was told of the Pharaoh Khufu,

the king who built the Great Pyramid.

Herodotus heard that he was a tyrant

who enslaved hundreds of thousands of people

to construct his great tomb.

But Herodotus was writing his histories

in the 5th century BC,

2000 years after the pyramids were built.

But Karen has uncovered more recent archaeological finds

that have suggested something very different.

[Karen] The pyramid workers are really the heart

of this construction process.

The pharaoh could have all the money in the world

to build his pyramid, but without a workforce to do it,

there's no pyramid.

And clearly, this was a massive construction project.

Even if it didn't take an army of a hundred thousand people,

there would still have been a large workforce required,

and that workforce would have needed food and shelter.

[indistinct chatter]

[narrator] In the late 1980s,

archaeologists went looking for it.

On a sandy plain south of the Great Pyramid,

they discovered a "lost city" buried beneath the earth.

It was an enormous complex of buildings.

To the west, there were larger dwellings,

possibly housing administrators and overseers.

To the east, on the banks of the Nile,

there was a large village of support staff.

Bakers and blacksmiths. Doctors and cooks.

And nestled in between were the homes

of the pyramid workers themselves.

[Karen] Archaeologists found evidence

for a series of large barracks

that would have comfortably held

40 to 50 individuals.

This wasn't the height of luxury by any means,

but neither were they slums.

And there's more evidence that suggests

these pyramid workers were looked after rather well.

They also found quantities of animal bone butchered,

indicating that these workers were fed

a really high-quality protein diet,

which would have been fairly unusual

for everyday workers at the time.

A nearby cemetery yielded skeletal remains

that showed that these individuals

often had broken bones

that were properly set and healed.

This was, in sum, a well-housed, well-fed,

and well-cared-for population.

This was not an army of slaves building the pyramids.

[narrator] Not indentured or enslaved laborers

who would have been worked to exhaustion,

disposed of as and when necessary.

The vision of slave laborers

forced to work under the punishing Egyptian sun

can now be debunked.

[dramatic music playing]

Today, many Egyptologists believe

that the pyramid workers were either conscripts

or volunteers for the great cause.

Master craftsmen may have been on-site full-time.

The precise cutting and setting of the outer stone particularly

was no work for amateurs.

But it's thought likely that there were thousands more

unskilled workers.

They served a limited term at Giza

before returning to the villages they came from.

[Karen] They worked together in teams.

We know this from graffiti

that has been found actually on the Pyramid.

In hidden little spots, workers wrote down

the names of their work gangs.

They made their marks on history.

And good for them.

Because although the Pyramid

was built for the pharaoh,

it was so much more.

The site of the Great Pyramid was more

than just a gigantic construction site.

It was a place of social transformation.

It was a place where individuals

who had probably never left their village

to come together for a period of time

to be involved in building this great monument,

not just to an individual leader,

but to their whole nation.

I mean, it was to the glory of Egypt,

and it fulfilled every very important religious belief

this society held dear.

[narrator] Together, they were shaping the pyramid,

and the pyramid was shaping them.

Thousands of Egyptians, hundreds of villages,

all now one people.

[clapping echoing]

[Karen] The pyramid workers are really the heart

of this construction process.

You know, the pharaoh could have all the money in the world

to build his pyramid, but without a workforce to do it,

there's no pyramid.

[narrator] The truthseekers have established that

the workers who built the Great Pyramid weren't slaves.

We know where they lived. What they ate.

The teams they worked in.

But there is one thing that is still unknown.

How did they build the Pyramid itself?

The Great Pyramid of Giza.

The largest of three gigantic monuments

on the west bank of the Nile.

It has stood for four and a half thousand years,

and its silent stones still hold many mysteries.

[dramatic music playing]

As our team of historians, archaeologists, and scientists

continue on their quest to uncover its truths,

one of the biggest questions is exactly how

was this marvel of ancient engineering constructed.

This structure still continues to fascinate,

being four and a half thousand years old,

140 meters high.

Just how exactly did people build this?

We're still wrestling with this question,

as the Romans did centuries ago.

I'm Tony McMahon, and my approach to the past

is about investigating those mysteries

that have been seemingly impossible to solve.

Distinguishing fact from fiction.

Separating history from mystery.

[narrator] There is still little consensus around

how these massive structures were built.

Tony is looking at the engineering behind the pyramid,

and the most recent exploratory science

to examine the evidence and get to the truth.

[Tony] In two and a half thousand BC,

you have to imagine that the state of human technology

was still relatively primitive.

There are no sophisticated pulleys and cranes.

And yet, this enormous structure is created by people

at the earliest stages of human civilization.

[narrator] Most of the Great Pyramid

is constructed out of limestone quarried at Tura

just south of the construction site at Giza.

But there are 8,000 tones of granite

in the structure as well.

These gigantic blocks of stone

came from much further afield.

To reach Giza, they had to be transported

800 kilometers from Aswan in the south.

How did all this stone reach the construction site?

Could they really have done this unaided?

[Tony] There's been growing interest for many years

in how the pyramid was built,

and a fascinating document was discovered in 2013.

In an ancient harbor on the Red Sea coast,

the excavators discovered hundreds of fragments

of an intriguing document.

They were the oldest examples ever found of papyrus,

the thick, paper-like material

used to write on in Ancient Egypt.

The fragile document dated from the time

the Great Pyramid was being built.

This has been rightly called

the greatest discovery in Egyptology this century.

"The Diary of Merer,"

which is essentially inventory kept by an overseer,

but it gives an incredible insight

into the day-to-day building activity

that created the Great Pyramid.

[narrator] Merer was a mid-ranking official

at the quarries at Tura.

The quarries produced the finest quality

white limestone in Egypt.

On the Great Pyramid, it was used

for the outer shell of the monument.

When you go to the Great Pyramid today,

you're confronted by what is essentially

a huge mound of blocks.

But originally, the whole pyramid

was cased in limestone.

Its sides were smooth.

[narrator] The logbook found by the archaeologists in 2013

details the transportation of limestone

from the quarry to Giza.

What we learned from what the overseer Merer

wrote on that piece of papyrus

is that this was a very sophisticated operation

to build the Great Pyramid.

It involved the transporting

of huge blocks of stone

from quarries hundreds of miles away

using a system of canals and using the river Nile,

and this would have necessitated a national effort

in order to be able to conduct this kind of operation.

[narrator] Using hieroglyphics,

Merer recorded his team's work every day.

They hauled the heavy blocks down to the Nile on sledges,

where boats waited to carry them downriver.

The round trip took three days.

Over the five-month period in the log,

Merer's team of boatmen moved

around a thousand blocks of white limestone

to the construction site.

That's 20 blocks of limestone

weighing on average 2.5 tons each

being transported 20 kilometers.

They would have used the natural current of the Nile

to aid their return downstream to Giza,

but it remains impressive,

even by today's standards.

But getting the blocks to Giza was only part of the problem.

The stone still had to be taken

from the river to the construction site

and lifted into position on the pyramid.

[Tony] If we work on the assumption that

the Great Pyramid took about 20 years to build,

that means that they must have been laying down a block

every two minutes.

Now, that begs the question,

how on earth did they do that

with the technology of the time?

For at least 2,000 years,

it's been assumed by many analysts

that some kind of system of ramps was involved

to get those stones increasingly skyward.

But what kind of ramp?

[narrator] Ramps made of sun-dried mud bricks

have been found at other ancient Egyptian sites.

But the Great Pyramid would have required an enormous slope,

wide enough for teams of men to pass each other

and strong enough to carry blocks weighing many tons

up to the higher levels.

How would this have been possible?

Tony has been digging into the many different theories.

[intriguing music playing]

[Tony] If we take one of the ramp theories,

that there was one single mega ramp

up against the pyramid side, that's perfectly feasible.

But the problem is, there is no evidence

that such a ramp ever existed.

The great Roman writer Pliny

discounted the idea of a mega ramp,

but nevertheless, it's fascinating

that the Romans, who built on such an epic scale

all over the empire,

were nevertheless fascinated by this structure

that was already two and a half thousand years old

by the time that Pliny was writing.

[narrator] Over the centuries,

different forms of ramp have been suggested.

A zig-zag ramp that snaked up one side of the pyramid.

Or a spiral ramp that climbed around it

and encircled the whole structure.

But the problem is, there just isn't any evidence

for any of these external ramps,

and they all present logistical difficulties.

[no audio]

[narrator] This missing evidence

led one investigator

to a new theory.

In 1999, a French architect, Jean-Pierre Houdin

came up with an intriguing,

and, I think, quite plausible theory,

for how a ramp might have been used to build the pyramid.

So he believes that, initially,

there would have been an exterior ramp

to build the first two-thirds of the pyramid.

But then that external ramp was dismantled

and taken inside the pyramid

to use those building blocks

to create the last part of the pyramid,

but from the inside.

And that's why there's no sign of an external ramp.

[narrator] Houdin's theory is a controversial one.

Some Egyptologists claim his ideas are too complex.

That his internal ramp would weaken

the structure of the Great Pyramid.

But a mysterious discovery from the mid-1980s

suggests there may be more to Houdin's ideas

than his critics think.

[Tony] There had been an earlier study in 1986

with a microgravity detector

looking for hidden chambers within the Great Pyramid.

And there'd been a rather kind of mysterious

swirling pattern detected of lower-density material.

Now, that didn't seem to make much sense at the time,

but with Houdin's theory years later,

it does suddenly fit into the idea

of some kind of internal ramp system

being used to build the pyramid.

[narrator] There was a problem with Houdin's theory though.

How did these blocks of stone navigate around

the tight corners of his internal ramp?

Well, there must have been some kind of space

created in a system of notches,

in order to be able to maneuver those stones around.

[narrator] Houdin theorized that the ramp

twisted up through the inside of the pyramid,

and that where it turned, the structure

was initially left open.

Working with an American Egyptologist

called Bob Brier,

Houdin went looking for these notches.

In 2008, Brier was given permission

to climb the Great Pyramid.

He wanted a closer look at what he and Houdin

thought might be one of those openings

on the outside of the Pyramid.

[Tony] He went up about 80 meters,

when, on the northeast side,

he found a kind of uneven platform

and a niche into which he looked

and saw what he described as an L-shaped room.

Now, this kind of tallies with the idea

of blocks being moved internally,

and, of course, they'd have been very awkward to move.

If anybody's moved a sofa through a house,

they'll know what we're talking about here.

So you would have had to maneuver the block through,

and every so often push the block back into a space

in order to be able to turn it into position.

[narrator] The notch was exactly where Houdin's theory

predicted an opening would be found.

He was certain he had found a junction

where the structure was left open

to allow the great blocks to turn on their journey

up to the top of the pyramid.

But conclusive proof for Houdin's intriguing theory

is yet to be found.

There remains one other possibility.

That there is no evidence for a ramp

because there was no ramp.

In this daring theory,

the pyramid itself was the ramp.

[Tony] There are ancient Egyptian depictions

of huge objects, statues, for example,

being dragged along the ground using rope.

The Egyptians were very good at making rope.

Water, grease, and so on,

in order to slide these heavy weights along.

[narrator] Teams of men using ropes

could have pulled the blocks up either a wooden track

or along the polished outer stones

of the Pyramid itself.

A system of counterweights could have been used as well,

empty sledges returning to the ground

helping to lift the next stone up.

But, we're talking about heavyweights

not being slid along the ground,

but slid upwards.

And whether or not that's really feasible beggars belief.

[narrator] A straight ramp or a spiral ramp.

An internal ramp, or no ramp at all.

Each theory has its supporters.

Definitive evidence is yet to be found.

The hunt for the truth goes on.

But how the Egyptians completed the monument

is far from the only enigma of the Great Pyramid.

The greater mystery is why?

The countless stones of the Great Pyramid of Giza

still hold many secrets.

Over the centuries, they have inspired

wonder and curiosity.

As the team of scientists

continue sifting through the evidence

in their quest for clues, the focus now turns

to the real purpose of this monument.

In London, a team of scientists and historians

is sifting through the evidence,

searching for clues and seeking out the truth.

We now know who built it,

and we have got closer to understanding how.

But the biggest mystery is why?

What was this all for?

[narrator] Dr. Fern Riddell is a cultural historian.

She wants to know how we've seen

the pyramid throughout history,

what meaning have we given to its purpose,

and what clues that might provide.

[Fern] In ancient times, Greek historians like Herodotus

identified the Great Pyramid as a tomb

for the mighty Pharaoh Khufu.

But over the centuries,

there have been many other theories

about the purpose of the Great Pyramid,

all of which have added to the enduring mystery.

[narrator] Early scholars looked to the Bible

for an explanation for the massive structures

in the desert.

The Book of Genesis in the Old Testament

tells the story of an Egyptian pharaoh

who is troubled by his dreams.

[solemn music playing]

Firstly, he sees seven really fat cows,

followed by seven cows that are terribly lean

and staggering and sick.

Then he sees seven ears of corn

that are really fat and juicy,

followed by seven ears that are really thin and straggly.

And he wakes up terrified. What could this mean?

It turns out that in prison,

he has a young Jewish man named Joseph,

who can answer and interpret these dreams.

What Joseph says is there's going to be a terrible famine,

and the only way the pharaoh can save his people

is if he stockpiles as much food,

as much wheat, as he possibly can.

[indistinct chatter]

[narrator] Biblical scholars calculated that

vast structures must have been needed

to house all that grain.

At Giza, they thought they found them.

So this belief that the pyramids are the granaries of Joseph

really exists from the 6th century onwards.

By the 1200s, especially 1204,

this incredibly beautiful mural

is made in St. Mark's Cathedral in Venice,

depicting the pyramids as the granaries.

[narrator] For medieval Christians,

whose entire worldview was based on the Bible,

the granary myth was a convenient explanation,

but one that eventually began to be challenged.

By the 14th century, we have

an amazing travel memoir by John Mandeville.

And he says he sees the pyramids,

but while he agrees that they are the granaries,

there's kind of this air of confusion and hesitation.

And we know by the 15th and 16th century,

as trade and commerce, and, more importantly, tourism

really starts to kick off,

people see the pyramids for themselves,

and they start to realize the church was wrong.

The pyramids are such a mystery, though,

that just as the church was trying to explain them,

we're still trying to explain them today.

[narrator] There are still many who refuse to believe

the pyramids were created by the Ancient Egyptians.

They must have been built by an advanced civilization

now lost to history.

Or by aliens.

And they weren't tombs.

They were designed to produce rain

in the barren lands west of the Nile,

or to harness electro-magnetism as some gigantic power plant.

I think the reason why people prefer

those insane theories about aliens

or people levitating blocks,

is because the idea

that people four and a half thousand years ago

were cleverer than us, could build

these structures we still don't understand,

is one a lot of people don't really want to accept.

[narrator] Mysteries are littered with examples

of people not acknowledging

that our cousins from the ancient past

were smart, innovative,

and as capable as we are today.

And this has given birth to many strange theories.

[Fern] While these theories often sound crazy,

and many of them are,

they can tell us a lot about the people proposing them.

Their culture, their motivations,

their own obsessions and fears.

[narrator] One such man was the 19th-century astronomer,

Charles Piazzi Smyth.

Charles Piazzi Smyth was the Royal Astronomer for Scotland,

and he's a man who had an absolutely exceptional life.

At the age of 16, he was already traveling the world,

investigating time and space

and trying to fit and explain

all of these mysteries that we have to ordinary people.

[narrator] Smyth became obsessed with the Great Pyramid,

how it was built, and what its meaning was.

He was convinced it was built under the direction of God

by a lost tribe of Israelites

who went on to settle Britain.

In 1860, he tried to convince the Royal Society

to fund an expedition to Egypt

to solve this mystery once and for all.

The Royal Society, unfortunately, refused,

but that didn't stop him.

And Charles Piazzi Smyth took himself

and a number of other people out to Egypt

to answer this mystery of the Great Pyramids.

He did this by surveying

and creating an entirely new way

of measuring and understanding the Great Pyramid itself.

[narrator] Smyth claimed to have discovered

the unit of measurement used by the Ancient Egyptian architects.

The Pyramid Inch.

Every part of the Great Pyramid,

from the height of its blocks

to the width of its chambers,

was supposedly based on it.

[Fern] So the Great Pyramid inch is nearly identical

to the British inch, and this is something

that Charles Piazzi Smyth was very proud of.

He felt that it really showcased

how important the British system of measuring was for the world.

Because, at that time, people were really captivated

by this new thing called the metric system,

which had been invented in France

and was less than a hundred years old.

And Charles Piazzi Smyth felt that if you could measure

the Great Pyramid by British inches alone,

well, that was the way we had to go.

[narrator] Smyth's motivations weren't just driven

by the Victorian obsession with empire.

He felt that the Great Pyramid was a way

that humans communed with the heavens.

He calculated that the number of inches

in the perimeter of the base

matched the days in a solar century.

He also claimed that the height of the pyramid

was numerically related to the distance from Earth

to the sun.

[Fern] One of the things that Charles Piazzi Smyth

really believed was that England itself

represented one of the ten lost tribes of Israel.

And he felt that written into the stones of the Great Pyramid

was an answer and an explanation

that Britain had this kind of intense Christian heritage.

Of course, it's completely untrue,

but what it shows us is that kind of

Victorian imperialist attitude

to make white Europeans central to the story of the world.

[narrator] In 1867,

Smyth released a book about his obsession.

"Our Inheritance in the Great Pyramid"

was over 600 pages long,

but it quickly became a best-seller.

Smyth believed that the monument at Giza

was a model of the earth and its history,

from its beginning to its end.

By precisely measuring the pyramid,

he also fixed a date for the Apocalypse.

So, Charles Piazzi Smyth believed that

because the Grand Gallery in the Great Pyramid

measured 1,881 inches,

the world would probably end after 1881.

He believed from 1882 onwards,

the world would be plunged into revolution and war and chaos.

This would be the coming of the Antichrist,

even the second coming of Christ.

But basically, the Apocalypse was here.

One thing we have to understand is that the Victorian century

was full of apocalyptic cults

because this is a time of huge progress

and excitement and technology.

People fear change. They fear the end of the world.

The problem is, of course, when 1882 rolls around

and everything is fine,

your credibility is somewhat damaged.

And he is satirized in newspapers globally

across the Western world,

and it must have been a very painful time for him.

[narrator] Despite this humiliating failure,

inadvertently, Charles Piazzi Smyth was responsible

for one of the most important discoveries

ever made in the Great Pyramid.

In September 1872,

a British engineer was working in a chamber

deep within the Great Pyramid.

His name was Waynman Dixon.

He was testing joints between the masonry

on the south wall of the chamber

when he discovered that one of the stones sounded hollow.

Dixon broke through.

On the other side, he discovered a hidden shaft,

a small tunnel disappearing into the pyramid's interior.

Dixon then checked the north wall of the chamber

and found another secret shaft there too.

And that was not all.

At the bottom of one of the shafts,

he discovered three objects.

[Fern] So, Waynman Dixon found the only objects

that have ever been uncovered in the Great Pyramid,

and they were a copper hook, a dolerite stone ball,

and a cedarwood sample.

[narrator] Two of the Dixon Relics

are now in the British Museum.

The fragments of wood were given

to the University of Aberdeen in 1946

and promptly lost.

So these Dixon relics,

the copper hook and the stone balls,

stayed with the British Museum,

but the cedarwood sample went missing.

Abeer Eladany, an Egyptian curator

at the University of Aberdeen,

was investigating the holdings in 2020,

when her eye was suddenly drawn to a cigar box

that had an old Egyptian flag on it.

Opening it, she realized it was holding the remains

of the cedarwood sample from the Great Pyramid,

an unbelievable rediscovery.

[narrator] And a rediscovery when the wooden fragments

can be examined by modern science for the first time.

But carbon-dating a sample of the ancient wood

threw up an unexpected result.

[Fern] Radiocarbon dating is a way of measuring

the age of something that has organic material, like wood.

We all absorb carbon throughout our lives,

but when we die, it starts to decay.

And we have this incredible system

of measuring how much is left of it in a sample.

Radiocarbon dating has shown us

that the cedar wood sample is over 3,000 years old.

That's 500 years older than the Great Pyramid itself.

So it's this incredibly old bit of wood

in an already ancient building.

So, as always with the Great Pyramid,

you find one thing and it leads you

to a host of other mysteries.

[narrator] Today, Charles Piazzi Smyth's theories

about the Great Pyramid are almost forgotten.

Most scholars now agree

with the historians of Ancient Greece.

The Great Pyramid was built as a tomb,

the last resting place of the Pharaoh Khufu.

But Charles Piazzi Smyth's work left a legacy,

not only in his precise

measurements of the Great Pyramid,

but in the discoveries he made inside.

The shafts uncovered in 1872

may hold the key to unraveling

the final mysteries of the Pyramid.

The mysteries hidden within its stones.

The King's Chamber in the heart of the Great Pyramid.

It has stood empty for thousands of years.

But the enormous granite sarcophagus inside

once contained the mummified body of the Pharaoh Khufu.

So this age-old problem of what's inside the Great Pyramid,

that's something that still fascinates us,

and we're using the latest techniques,

the latest technologies, really,

to explore this question.

We're using thermography, even using nanoparticles

to understand what's going on inside the Great Pyramid.

Non-destructive ways, basically,

to get at this age-old problem.

And so we're finding hollows, we're finding cavities

within the Great Pyramid that mystify us.

[narrator] Dr. Mark Altaweel has been investigating

the mysteries of the pyramid's interior.

When the Great Pyramid was completed, it was sealed up.

Its interiors were never meant to be disturbed.

But that didn't last.

Nobody knows who first breached the Great Pyramid or when.

The first recorded exploration

came more than three thousand years after it was built.

So, the way they broke into the pyramid

was basically hacking.

It's literally a hack job, using spears, even fire,

to sort of crack the rock and move it away.

So they used whatever metal tools they had, literally,

but mostly spears and sometimes fire

to kind of try to crack the rock effectively

and get into the pyramid.

[narrator] By then, the great Egyptian Empire

ruled over by Khufu was long gone.

Egypt had been conquered by foreign powers

again and again.

First came the Persians in the 6th century BC.

Then it was the forces of Alexander the Great.

In 30 BC, Egypt was annexed into the Roman Empire

and ruled by the Caesars for the next 600 years

until it was conquered by the Rashidun Caliphate.

The Great Pyramid witnessed all this change,

but across those many centuries,

we have no record of anyone going inside.

Nothing until the 9th century.

The ruler of the Rashidun Caliphate, Al-Ma'mun,

ordered his men to tunnel into the Great Pyramid.

They smashed their way into the north side,

approximately 17 meters up the slope.

[Mark] So it was quite a substantial effort.

They tunneled through 27 meters of rock.

I mean, you'd think after a few meters,

it's really hard going work removing all those stones

and giant boulders, really.

Yet they were able to kind of go through this,

eventually reaching an endpoint.

[narrator] What the men of Al-Ma'mun found

when they emerged from their tunnel was a passageway.

It was low and cramped.

When the men looked down it, they saw

that the passageway was blocked.

Three great granite stones sealed off the entrance.

[Mark] Whatever lay at the other end of this narrow tunnel

was something the builders of the Great Pyramid

wanted to protect.

So, of course, these explorers

followed this passageway.

They went another 30 or so meters,

stooping because the ceilings are so low.

And then they emerged into the Grand Gallery.

[narrator] With walls of finely jointed granite,

the Grand Gallery slopes upwards,

cutting deeper into the heart of the pyramid.

[Mark] So, the Grand Gallery is a bit of a deceptive name.

It's really a shaft. Ascending shaft.

It's about 46 meters long, nine meters in depth,

and about two plus meters in width,

and actually decorated with nothing.

[narrator] The men of Al-Ma'mun climbed the slanted gallery.

A low doorway led to an antechamber,

and, beyond that, the room the Pyramid builders

had tried so hard to protect.

A large chamber clad in smooth, dark red granite.

[Mark] So they walk through the passageway,

the shaft that connects up to the Grand Chamber,

what's called the King's Chamber,

and they do find one thing, a sarcophagus.

But unfortunately, it was empty.

There was absolutely nothing else in that room.

A relatively undecorated room

with a large sarcophagus.

So, it does look like a place fit for the king,

given its size and large sarcophagus.

But no treasures, nothing else to be found.

So the question emerges, what happened?

What happened to Pharaoh, his body, the mummy,

as well as what happened to the treasures?

[narrator] The burials of wealthy Ancient Egyptians

were lavish.

A great pharaoh such as Khufu

would have been mummified,

his body wrapped in linen bandages,

and placed in an ornate coffin.

Accompanying him into the afterlife

would have been vast quantities

of treasure, furniture, and jewelry.

So, two main theories emerge.

One is, of course, you see an empty chamber

that looks appropriate for a burial

for a king, for a pharaoh, and you see nothing there,

you just assume, well, then maybe it was robbed,

that the treasures were stolen.

But a second idea is potentially

that the ancient Egyptians, of course,

knew tombs will be robbed.

So they would have potentially

created a fake or false chamber,

right, kind of dead passageway, if you will,

leading into a chamber that has absolutely nothing in it.

[narrator] Over the centuries, other explorers

have dug deeper into the dark and airless interiors

of the Great Pyramid.

The large room with the sarcophagus

has been dubbed the King's Chamber.

A "Queen's Chamber" lies below it,

linked to the Grand Gallery by a horizontal corridor.

And down another passageway, beneath the pyramid,

buried into the bedrock itself,

is a subterranean chamber.

[Mark] Most pyramids, you have a burial chamber,

and usually that's below the entryway,

kind of even subterranean, really.

That sort of derives from the old tradition of the mastabas,

the ancient pre-Pharaonic tombs, which were usually subterranean.

So what's strange about the Great Pyramid

is that you have this upper chamber,

or this chamber where, you think, perhaps

Pharaoh may have been buried.

So that's quite different from other pyramids.

The purpose of all these rooms

in Khufu's pyramid is mysterious.

If we assume the King's Chamber was the burial chamber,

then what were the others for?

The subterranean chamber is clearly unfinished

and there was no Queen in the "Queen Chamber,"

that was just a name given to it.

And this is not the only mystery.

[narrator] In both the King's Chamber and the Queen's Chamber,

narrow shafts disappear into the pyramid's interior

from the north and south walls.

There are shafts in the King's Chamber

that extend all the way to the outside

of the pyramid.

There are also the narrow tunnels

discovered by Charles Piazzi Smyth's engineer

in 1872.

The purpose of these shafts continues to perplex scientists.

[Mark] What's really strange about that is that

the shafts actually don't appear

to have any connection to the outside.

They just seem like little narrow tunnels

that go through the pyramid but mysteriously end

or reach to what looks like a door,

a kind of passageway, perhaps.

So we don't actually quite know where these shafts go.

[narrator] In 1993,

a team of German archaeologists

sent a robot up the shaft

in the southern wall of the Queen's Chamber.

[Mark] So one of the times, they sent these robots.

They went further along, about 63 meters up the shaft

in the Queen's Chamber,

and they see a door, or a kind of passageway,

blocked by a limestone block,

but with two hinges, these kind of copper hinges,

that seem to be connecting to the rest of the pyramid.

So, something was meant to pass through there.

[narrator] This block wasn't the roughhewn limestone

that makes up most of the pyramid.

It was the Tura white limestone,

the high-quality material that decorated

the outside of the pyramid.

But why was it used here?

And the purpose of the copper hinges

baffled the archaeologists.

Later projects tried to solve the mystery.

More advanced robots climbed into the shaft.

They went even further.

Drilling a tiny hole through the stone door,

scientists were able to photograph the other side.

[Mark] It found another potential passageway.

So, it doesn't quite end, but mysteriously,

another passage that leads to some other place,

as well as inscriptions, and what looks like

decorations with some paint.

So it's clear that this is some kind of

significant passage of these shafts.

But what was it used for? It's unclear.

We don't have the answer yet. The shaft might continue.

There might be other chambers.

There could even be signs of Houdin's internal ramp.

These were obviously built with a purpose in mind.

There could be some sort of ritual or religious reason.

[narrator] In Egyptian religion of the time,

a watery realm called the Abyss

lay beneath the ground and beyond the stars.

It was these cosmic waters

that gave new life to the dead,

much as the annual flooding of the Nile

gave life to the lands of Egypt.

Traditionally, Egyptian burials

were underground, in the Abyss.

But in the Great Pyramid, the pharaoh's tomb

was high in the structure,

lifted above the earth,

above the realm of the Abyss.

The cosmic waters relates back to the creation myth, really.

In ancient Egypt, pyramids themselves

are meant to sort of be kind of like

mounds covering something

where the creation myth of how Earth came about

was basically a giant mound

with the cosmic waters coming out.

And so, perhaps, this means the shafts

actually brought water to the pyramids,

it brought water to the burial of Pharaoh.

And Pharaoh, of course, considered himself a god.

So being a god, you want to bend reality to you.

It certainly would have been a grand gesture,

a grand kind of display of how mighty Pharaoh was.

[narrator] It's possible that all the chambers in the pyramid

could have been used as tombs.

If the Pharaoh Khufu died

before his monument was completed,

he could be placed in one of the lower vaults.

The subterranean pit was started first.

But it was abandoned unfinished

once the Queen's Chamber higher up was completed.

Then the larger King's Chamber was made ready above.

The pharaoh was still alive at this point,

so the Queen's Chamber, with its ritual shafts

pointing north and south,

was no longer needed.

[Mark] The two shafts were then sealed up

and forgotten until an explorer came along.

[narrator] The search goes on.

In 2017, scientists scanned the Great Pyramid once again.

Using thermal imagery

and measuring the variations

in cosmic rays known as muons,

they made a remarkable discovery.

Evidence of another, previously unseen chamber

located above the Grand Gallery.

Its exact size and shape are still unknown.

Its purpose is yet another mystery.

It seems in the vast darkness of the Great Pyramid,

there are still more secrets to be found.

We have discovered that the pyramid workers were not slaves,

but worked together to build a new Egypt.

[Karen] The site of the Great Pyramid

was more than just a gigantic construction site.

It was a place of social transformation,

to be involved in building this great monument,

not just to an individual leader,

but to their whole nation.

I mean, it was to the glory of Egypt,

and it fulfilled every very important religious belief

this society held dear.

[narrator] We have explored how they might have built

such a monument.

[Fern] The idea that people

four and a half thousand years ago

were cleverer than us,

could build these structures

we still don't understand,

is one a lot of people don't really want to accept.

[narrator] And we've examined the reasons why they did it.

I think it would have been miraculous from the period.

Certainly would have been a grand gesture,

display, of how mighty Pharaoh was.

[narrator] But even after centuries

of exploration and research,

the tomb of Khufu still clings to its secrets.

The work of historians and scientists goes on

to unravel the Great Pyramid's mysteries

and seek out the truth.

The Great Pyramid has inspired historians

for generations,

and will continue to do so.

[Mark] There's so much we've learned,

but there's still so much to learn.

It's incredible how alive

this investigation is,

four and a half thousand years on.

New technologies are being developed all the time.

I think the answers are out there.

It will be an adventure, finding out.

[epic music playing]