Original subtitles

[Josh] Tonight, on an unprecedented "Expedition Unknown" event.

Are you kidding me?

I'm exploring one of the Seven Wonders of the Ancient World.

You really don't get how huge this thing is

until you're right up next to it.

The Great Pyramid of Giza.

I happen to have the key.

[Josh] And you've got an all-access pass to go inside...

We're in.

...and unravel its greatest mysteries.

-Look at this. -How was it really built?

[Soren] They're inventing a survey system

to build the Great Pyramid.

[Josh] Where is the missing mummy of the pharaoh?

One glaring problem here, no Khufu.

And is his treasure-filled tomb still hiding within?

-It should be right here behind this rock. -Yeah.

[Josh] Now, the secrets of the pyramid will be unlocked.

What the hell is this?

And jaw-dropping discoveries will be revealed.

Oh, it's just sensational.

Hey, here we go!

[divers speaking]

It's incredible.

I've never seen anything like this.

What is that? Oh, my God, that's writing.

[shouting]

Whoa! It's working!

We could be looking at a lost passage in the Great Pyramid.

It is a lost passage.

[Josh] The deserts of Egypt.

The ultimate blank canvas.

Nothing but sand, wind, and history.

Thousands of years before the Greeks crowned

the Acropolis with marble columns,

or China constructed the Great Wall,

a monument of geometric perfection pierced

the horizon and reached for the sun.

Hyah!

[dramatic music playing]

This is the Great Pyramid of Khufu,

the first man-made structure to define an empire.

It is one of the greatest engineering feats of all time,

and it has captivated everybody from Alexander the Great

to Napoleon -- hell, even Mr. Beast came here.

And for my entire life, indeed for centuries,

people have been spinning some wild theories

about this building.

Some contend it has intense spiritual power,

others imagine alien architects

or the handiwork of a lost advanced civilization.

After all, how could ancient people

four and a half millennia ago,

build something so perfect without modern tools,

without the wheel?

Many have said it's basically impossible, that its alignment

is too mathematically precise,

its method of construction utterly baffling.

And many say that inside, there may be hidden chambers,

or perhaps even a missing pharaoh.

Several years ago, scientists, using remote sensing technology,

claimed to find evidence of voids inside the pyramid

that may be undiscovered passages or the lost tomb.

And just recently, an Italian team set off

an internet feeding frenzy,

contending that they've discovered massive columns

beneath the Great Pyramid,

which some have gone so far as to say is an ancient engine

or energy source.

The mysteries are as big as the pyramid itself,

and so I'm here to find answers.

A first-ever laser map

could tell us if there are concealed chambers

inside the pyramid that have never been discovered,

possibly even the riches of a lost pharaoh's tomb.

Researchers are also performing a groundbreaking series

of 3D scans that may reveal how the pyramid

is so perfectly aligned.

And on the edge of the Red Sea,

archaeologists are excavating long-hidden caves

that are exposing the biggest mystery of all --

how the pyramid was actually built.

So get ready to gawk like an Egyptian as we explore

inside humanity's ultimate monument and biggest mystery

to finally reveal the secrets of the Great Pyramid.

Hyah!

The past is all around us...

Oh, my God! It goes on forever!

...a world of mystery...

Come on! Look at that!

...danger...

Hang on!

...and adventure.

It's just straight down.

I got to get a new job.

I travel to the far corners of the Earth

to uncover where legends end... -Yeah!

I got it!

-Yes! -...and history begins.

Whoo-hoo!

Here we go.

I'm Josh Gates,

and this is "Expedition Unknown."

[fast-paced folk music plays]

Cairo, city of the living.

This is the dusty, beating heart of modern Egypt,

home to 23 million people.

Africa's ultimate megacity is crowded, chaotic,

but never dull.

This is a place of momentum and mystery.

Tourism is the new king in Egypt,

and the local bazaar has enough tchotchkes

for each and every one of the 15 million annual visitors.

We got big pyramids, little pyramids,

pyramids inside pyramids, pyramid T-shirts,

whatever this is,

not to mention enough mummies to make Brendan Fraser jealous.

Does it contain a tiny mummy?

It does contain a tiny mummy. Yep.

And some of them are even functional.

What does that do? Ah!

This and all the other hardware is here so people

can have a keepsake to remember

the single most unforgettable structure on Earth.

It is easily the first and best case of branding in history,

and it's all thanks to this guy.

Meet Khufu.

This tiny statuette is a replica of the only surviving

depiction of the pharaoh who commissioned

the Great Pyramid.

And despite building the only wonder of the ancient world

that's still standing, he actually wasn't the first guy

to try to put a triangle in the sky.

All right, fasten your seat belts.

Time for a history lesson.

Da-Nile [Denial]!

It's not just a river in Egypt, but in this case, it is.

And this life-giving source of water is why Egypt becomes

a thing in the first place.

People start populating the banks of the Nile

in about 7,000 B.C.

Annual floods here create soil that make the Egyptians really

good at growing things, and they also fight

a fair amount -- take it easy, guys.

That is until this guy, the first pharaoh, Narmer,

unites Upper and Lower Egypt into a single kingdom

around 3,100 B.C.

This is also when single-story tombs called mastabas start

appearing, which are the Cadillac of burials for

the early Egyptian elite. -Sweet Mastaba, dude.

[Josh] Jump ahead 500 years later,

and the third dynasty pharaoh Gozer -- no, wait,

that's "Ghostbusters."

Sorry, the pharaoh Djoser has a higher vision,

literally, with mastabas stacked one on top of the other.

And just like that, the high-rise arms race begins

with Djoser's layer-cake tomb, the Step Pyramid.

Later, the pharaoh Sneferu wants his own pyramid

but doesn't love all those crinkly edges.

The architecture proves tricky.

His first effort collapses, and the second turns out

a little, eh, bent.

The third time's the charm, though, and he creates

the first flat-sided pyramid known as the Red Pyramid.

Then, around 2600 B.C., Sneferu's son Khufu,

in a classic case of, "Dad, don't tell me what I can't do,"

decides to supersize his father's innovation

and build this.

The first thing that surprises most people

about the Great Pyramid, other than its enormous scale,

is that it doesn't just stand alone here in the desert.

These sands are surrounded on all sides by the ever-expanding

metropolis of Greater Cairo,

and the Giza Plateau that it sits on was once part

of an ancient necropolis that, back in the day,

was a mini city of its own.

The Giza Plateau is actually home to nine pyramids,

not to mention multiple temples,

cemeteries, and this little beauty, the Sphinx,

which in their heyday were all surrounded

by plazas paved with meticulously-placed stones.

The two large pyramids next to Khufu's were built by his son

Khafre and grandson Menkaure, respectively, but neither is

larger or more impressive than the original.

I mean, it's not called the Great Pyramid

because it's the third best one here.

It stands nearly 45 stories tall

and weighs an estimated 6 million tons.

It's made up of more than 2 million individual limestone blocks

and is aligned to the cardinal directions

with incredible precision.

It's nearly perfectly level, and the area that it sits on is

the size of 10 football fields.

None of these facts are in dispute.

But when it comes to the Great Pyramid,

just about everything else is subject to a lot of opinions.

And those opinions can get downright eccentric.

The idea that the pyramid is full of secrets or wasn't built

by ancient Egyptians has been with us since the first

European explorers rolled in.

Then, in the 20th century, self-proclaimed psychic,

Edgar Cayce, proposed a link to Atlantis.

And author Erich von Däniken

popularized extraterrestrial intervention,

an idea that that's been in popular culture ever since.

And now the internet has taken up the baton with viral posts

about secret chambers and hidden underground columns.

It's time to find out the truth.

So I reached out to the expert on all things

Great Pyramid, Dr. Mark Lehner.

-Josh. -[Josh] Great to meet you.

-Good to see you here. -[Josh] Yeah.

Mark has been mapping and studying the Giza Plateau

for more than 50 years and is the author of big heavy books

such as "Giza and the Pyramids" and "The Complete Pyramids."

In other words, this guy knows what he's talking about.

This pyramid, I think, has inspired more mysteries,

more questions, more conspiracies than any

other building on Earth. -That's a fair statement, yeah.

[Josh] These big questions about the pyramid come down to

the what, the who, and the how.

Let's start with the what.

So, at its most basic, what is this thing?

So, at its most basic, this thing is a tomb.

It's a tomb. And why a pyramid?

I mean, we know that in later parts

of ancient Egyptian history,

they abandoned this whole pyramid.

Why a pyramid? You want the answer?

-[Josh] Yeah. -We don't know, but...

-[laughing] -No, but what we surmise

from what evidence we have is that they were developing

this worship of the sun.

They were starting to believe the pharaoh

was the son of the sun,

so divinely incarnated from the sun god itself.

By making a pyramid shape, it's like the rays of the sun

that breaks through a cloud.

But by cladding it with polished white limestone,

it must have been as highly reflective

as newly-fallen snow.

[Josh] Today, the Great Pyramid looks nothing like it did

when it was new.

What appear to be limestone steps to us are actually

the pyramid's inner core, which was originally covered in

an outer casing of smooth white limestone

that was polished to a mirror shine.

And at the top, it may even have had a golden capstone,

radiating light like a sun here on Earth.

And so now the million-dollar question.

Who built this?

The pharaoh Khufu, who reigned about 4,600 years ago,

or about 2,600 B.C.

[Josh] Surprisingly little is known about Khufu,

since almost no inscriptions about his reign survive.

The Greek historian Herodotus claimed he was a cruel tyrant,

though there's zero evidence to support that.

Later Egyptians regarded him as a wise ruler.

What we do know is that he was the second pharaoh

of Egypt's fourth dynasty,

a golden age of prosperity and trade.

He sent troops on expeditions abroad in search

of precious materials like copper and turquoise,

and enjoyed a long reign of nearly 30 years.

And we can surmise that he was a very powerful king.

After all, he commissioned his own

monumental tomb, a building project that still

captivates the entire world 4,600 years later.

There have been so many kooky, fringy theories

about the pyramid, right?

But one thing that all those theories have in common is that

it always has to do with energy.

You know what?

In that, they agree with the ancient Egyptians.

It's all about energy. They called that energy, "Ka."

[Josh] Ka, life force of the ancient Egyptians.

It was a person's spirit energy, or ethereal double,

which remained tethered to his body in death.

Khufu, who was considered a god on Earth, would have designed

a grand tomb to act as a gateway to the afterlife.

It held his granite sarcophagus, his gilded mummy,

weapons, statues, food, and kingly riches.

His burial even contained so-called solar boats to carry

him to the heavens, so massive they were housed outside

the building at the foot of the pyramid.

The entire structure was a kind of spiritual battery for his Ka

to be stored and nourished.

-This building is a resurrection machine. -I love that.

OK, so at the end of the day though,

this is a tomb for Khufu,

and he's somewhere inside there.

Simple as that. No more mysteries.

We're good, right?

Well, Josh, that's where it gets complicated.

I'm afraid there are still mysteries.

And some of those mysteries are about

what's inside the pyramid.

And if you really want to understand,

we got to go inside. -Can you show me?

-[Mark] Yeah. Let's go. -Come on.

Boy, you know, you really don't get how huge

this thing is until you're right up next to it.

Standing at 481 feet, the Great Pyramid of Giza was

not only the tallest building in the world when it was built,

but it was such a feat of engineering that it remained

the tallest building in the world for nearly 4,000 years.

-[Mark] The entrance is up here. -[Josh] OK, we're going up.

[Mark] Yeah.

The steps, of course, are modern.

[Josh] Mark leads me up the side of the pyramid,

hopping over a barricade.

That's because we're going to the now-off-limits front door.

Wow!

Well, Josh, welcome to the original entrance to

the Great Pyramid.

This is insane.

I've been to the Great Pyramid before.

I have never been up here.

Well, you see, the entrance itself is this

three-foot-square little hole.

This is the original entrance down here?

This is the original entrance.

These angled blocks, these are called the chevrons, right?

Yeah, the French call them chevrons.

The size of those is obscene.

Each immense 80-ton chevron block is placed to protect

the tiny three-foot entrance in a technique

known as saddle vaulting.

There are actually five levels of chevrons here, which help

distribute the massive weight of the building above by

directing it off to the sides.

And the chevrons themselves are resting

on a colossal crossing block called a lintel.

Like, look at the size of this lintel block here.

Well, they think this maybe weighs 100 tons.

[Josh] But as impressive as all of this is,

none of it was meant to be seen.

Same for the door, which was hidden from view by

the pyramid's outer-facing stones.

OK, it occurs to me that one of the problems with being

a pharaoh who wants to be entombed for all eternity with

your kingly treasures is that by putting yourself

in this pyramid, you're kind of painting a target on it.

-Exactly -- I mean, it's the biggest building in the world. -[Josh] Literally.

And it's blazing with sunlight reflected off the white casing.

It's as though saying, "If you want to get me,

I'm here." -Right.

So how did Khufu then protect himself

from looters coming in here?

Well, he designed a totally unique set of chambers,

basically a series of locks,

comprising three principal lines of defense.

And it's almost like "Indiana Jones."

Get through one, you have to get through the other,

and you have to get through the other,

then you get to his treasure.

But Khufu was confident

that nobody could unlock that machine.

But no lock is unpickable,

so who do we think is the first one to get in here?

The tradition is that it was caliph, kind of like a sultan,

al-Ma'mun, in 832 A.D.

[Josh] According to the story, the caliph al-Ma'mun,

who ruled over much of the Arab world, orders his men to break

into the monument.

But with the main door hidden by the pyramid's outer casing,

the caliph's men make their own entrance.

We climb down to find a noticeable wound

in the side of the structure.

Josh, this is the entrance to the Robber's Tunnel.

So, they literally chiseled into the core of

the pyramid itself.

They chiseled, they smashed, they pounded, they built fires,

they heated the rock, they poured cold vinegar on it,

and blasted their way in. It was hard.

-It was hard work. -All right, well...

I happen to have the key, just for you.

-I mean... -[Mark] We can get ourselves in.

Key to the Great Pyramid. Hard to beat.

-Look at this. -[Mark] Oh, here we go.

[Josh] With Mark taking the lead, we've got rare private access

to the entire pyramid, including sections that are

off-limits to the public.

[Mark] Yeah, we're in.

-And we're in. -And we're in.

[Josh] Here we go.

[Mark] Yeah, we're in.

[Josh] Here you go.

Oh. Cool.

[Josh] Look at this.

I'm in Egypt deciphering the mysteries

of the Great Pyramid of Giza

with renowned archaeologist Mark Lehner.

To find the truth about what's really inside this structure,

we've got a rare all-access pass to explore and map

every square inch of it,

starting with the so-called Robber's Tunnel.

See, there's no finished faces, Josh.

Everything is rough.

They basically just bashed their way through.

You can actually see the original mortar stuffed

between the stones.

For the robbers, there must have been this real stress of

whether all of this was gonna stay up above their heads.

They didn't know, but probably they didn't want

to think about it -- probably best we don't either.

I mean, I'm looking up at this gigantic block.

Yeah, now here you can actually see some of

those blocks are just hanging, aren't they?

[Josh] Yeah, let's not think about it.

-So let's take a look at where we are here. -[Mark] OK.

So we have a tracker here so we can see where we are

in the pyramid. -[Mark] Right, uh-huh.

[Josh] We're able to chart our position in real time.

So far, we've come about 75 feet

into the Robber's Tunnel,

bypassing the main entrance above us.

Using the tracker, we'll be able to map and reveal

every inch of the pyramid's interior.

And so we're in this Robber's Tunnel now,

and we're going relatively straight back

into the core of the pyramid.

But you see, notice at the end how it hooks to the left?

[Josh] Yeah, what's going on up there?

At that turn, things get really interesting.

-Lead on. -OK.

[Josh] Wow.

Oh, hold on, this is like a lot to take in.

So they blasted their way in, hooked a left,

and then they tunneled down and up.

Right.

[Josh] When the robbers pushed into the pyramid,

they bypassed Khufu's first lock, the hidden front door,

and found two passages at this junction,

what's known as the Descending Passage,

which begins under the chevrons at the original entrance

and descends down to this point,

where it meets up with another passage,

the so-called Ascending Passage

that goes up into the heart of the pyramid,

a passage that appears partially blocked

by granite slabs.

And I can't help but notice these giant stone blocks here.

That is basically a line of defense against any robbers

that would get in -- why granite?

Because Josh, granite is so hard to break through.

[Josh] As the builders exited the pyramid,

they engaged Khufu's second locking mechanism behind them.

These nearly three-ton granite blocks were released,

sliding down and wedging tightly into place,

sealing off the Ascending Passage,

as well as, presumably, Khufu's tomb and treasure.

Like soap bars, they boom, boom,

boom, and sliding down, boom, boom, boom.

And that closed the upper part of the pyramid.

That's pretty "Goonies."

-Pretty...? -"Goonies."

-"Goonies?" -[Josh] Yeah.

-Really? -Well, I'll show it to you later.

-It's a great movie. -[Mark laughing]

[Josh] And just like "The Goonies," the robbers who broke in here

defeated this "booty" trap by tunneling around it into

the Ascending Passage -- now it's our turn.

[Mark] Now, it's gonna be tight.

We're gonna have to crouch over,

but then things change dramatically.

OK, so not for the claustrophobic.

It's not for the claustrophobic,

but it's well worth the climb. -Lead on.

Here we go, going up.

This passage is just 3 and a half by 4 feet

and ramps uphill at a 26-degree angle.

Well, you weren't kidding, that is tight!

[Mark] Can you imagine coming up here without the wooden walkway?

[Josh] Oh, my gosh!

I mean, this just goes on forever!

It's not an easy climb, but at the end is one of

the pyramid's biggest mysteries, literally.

[Mark] Josh, welcome to the Grand Gallery!

[Josh] Wow!

Oh, it's just sensational!

[Mark] It's one of the marvels of the ancient world.

It's insane! Look at this place!

[Mark] Yeah, we can get up in there on these ladders.

[Josh] Wow!

I mean, this is...

without a doubt one of the most...

truly spectacular and really mysterious rooms ever built.

If we look at where we are, we are now way up

inside the pyramid.

We're mapping the interior as we go,

having climbed 129 feet up a steep grade

in the so-called Ascending Passage to arrive

at the heart of the pyramid in the Grand Gallery.

It's seven feet wide and over 150 feet long,

with nearly 30-foot ceilings.

If there was ever a reason to be a conspiracy theorist,

this is the room.

[Mark] It would do it for you, and yet...

Well, it is sort of alien.

Above and around us are six million tons of stone,

held at bay by some extremely

otherworldly-looking engineering.

In reality, the principle is simple,

known as corbelled vaulting.

This ancient breakthrough uses slightly overlapping stones to

taper the walls inward,

redistributing the weight above it.

But there's one mystery about the Grand Gallery that may

never be solved -- why they bothered to build it.

Josh, you know, it was never meant to be seen.

So why? What is its purpose?

Yeah, what is this for?

[Mark] You could think it was like a cathedral in terms of

its loftiness and its effect, you know, on the human soul.

But nobody was ever gonna come in here?

Nobody was ever meant to come in here,

and it was never meant to be seen.

-Want to see where it leads? -[Mark] Yeah.

-Good to go. -Let's go.

[Josh] We make our way like ants through the soaring heights of

the Grand Gallery, climbing up a large step at the end.

And we got one more passage ahead of us here.

Ahead, we slip through a small opening to a narrow chamber

beyond and encounter Khufu's third and final defense.

What is this?

This is known as the Antechamber,

and it's basically a big locking mechanism.

So what you have here are these bars of stone in the granite.

They defined these slots -- one, two, three,

for sliding stones.

[Josh] This room above the Grand Gallery was sealed

with granite slabs set into notches,

putting an extra 20 tons or so of solid rock

between any would-be thieves and the king.

-It's like an ancient padlock. -[Mark] It is.

-Call it a padlock. -[Josh] Yeah.

With pins and springs, and...

[Mark] And where you release the springs

it basically shut the pyramid down.

It's amazing, and this is totally unique.

[Josh] But the robbers who entered here

more than a thousand years ago were undeterred,

either prying up the panels

or bashing through them, desperate to find the pharaoh

and his riches.

Then, finally, we're at the final destination

of this whole system, presumably where they put the king's mummy

to rest for all time. -The King's Chamber.

The King's Chamber, in this case, appropriately named.

OK, the King's Chamber.

We're only steps from the reason for this entire

monument, a breath away from the burial chamber of Khufu.

Oh, look at this room!

[Josh] Wow.

[Mark] You know, it's impressive in its simplicity,

just because of its size,

and it's all granite. -It is beyond impressive.

Exploring the Great Pyramid of Giza,

archaeologist Mark Lehner and I have entered

the so-called King's Chamber.

We are now 141 feet high inside the monument,

in a 35-foot-long rectangular chamber

fit for a god-king.

The room is clad in massive blocks of red granite,

including nine immense ceiling slabs

that weigh up to 40 tons each.

The size of this room, considering the amount of stone

around us, is, like, totally improbable.

[Mark] Indeed.

[Josh] In fact, that much weight above a flat ceiling

should be, well, impossible.

In 1837, British Egyptologist Colonel Howard Vyse

felt the same way.

So he did what any 19th-century explorer would do.

He used gunpowder to blast a hole.

And above the King's Chamber, Weiss discovered five

independent chambers stacked on top of each other,

capped by huge granite chevrons,

all designed to keep the enormous weight

of the pyramid from collapsing the room below.

Inside these so-called relieving chambers,

the 19th-century explorers carved graffiti on the walls.

But it turns out, so did the original builders,

leaving behind the only ancient writing found anywhere

inside the Great Pyramid.

In these chambers, they found painted lines

in red paint, giving measurements, giving level lines,

and giving the names of the work gangs who were

actually working on building this incredible...

set of structures.

[Josh] Alien theorists, take note.

These construction marks and names of workers are

the kind of thing you might find scribbled behind

the drywall of any building site today.

This shows us the unmistakable human hands

behind this project.

And those hands built other hidden features here.

-We also see these small holes. -[Mark] Right.

And these small holes...

are called air passages because they were formed like a gutter.

[Josh] These eight-inch-square shafts run more than 200 feet to

the exterior of the pyramid.

Their purpose is debated, but most scholars see them as

symbolic, perhaps allowing the pharaoh's Ka, or spirit,

to exit the tomb.

They may also align with stars

significant to Egyptian cosmology.

But the most important thing is right behind you.

-[Josh] This -- -The sarcophagus.

[Josh] This is it, the sarcophagus.

-Now, we have this amazing chamber. -[Mark] Right?

This unbelievable granite construction.

-Right. -So one glaring problem here,

no Khufu.

-[Mark] Right. -He's not here.

He's not here.

[Josh] And this is where things get weird.

When caliph al-Ma'mun's men first entered the King's Chamber

in the 9th century, the room and the sarcophagus

were reportedly empty,

and no significant treasure was found.

So, is there a chance that the reason they didn't find

his body here is because he was never buried here?

-There's a chance. -There is?

It's possible that the real burial

of the king is elsewhere.

I keep my mind open to that idea,

with even some ideas as elsewhere meaning where?

Have we been everywhere?

No.

In fact, every answer to every question that you're asking

right now is complicated by the fact that there are

two other chambers lower in the pyramids.

Can we see them?

You need to see them to see the full story.

Does that mean we're going back down?

That means going way, way down.

-OK, let's go. -All right.

[Josh] To reach the first of these chambers, Mark leads us out of

the King's Chamber and back to the bottom

of the Grand Gallery,

where a tiny portal near the entrance leads

to a long horizontal passage.

Oh, this is tough.

It's a tight fit.

So we're basically just traveling underneath

the Grand Gallery right now? -[Mark] Yeah.

[Josh] And at the end, another impressive room.

-[Josh] Wow. -Yeah, Josh.

Welcome to the so-called Queen's Chamber.

[Josh] So here we have another huge chamber,

different than the King's Chamber.

We don't have this red granite lined --

Nope, all white limestone.

[Josh] And while archaeologists have dubbed it the Queen's Chamber,

there's no evidence it was ever meant for a queen.

The room was found empty.

And like the King's Chamber, it also has two strange

ventilation shafts, but these are even stranger.

From here in the Queen's Chamber, the shafts extend

seven feet and then angle upward at 32 degrees

for nearly 250 feet, appearing to dead-end inside the pyramid.

Several decades ago, archaeologists started sending

robotic explorers into these puzzling shafts.

In 2002, one of them discovered a limestone door of sorts with

two copper handles on it.

In 2011, a robot named Jetty was able to drill a hole

through it and found another small chamber behind it.

A next-gen robot will be deployed here in the coming

years, but it seems unlikely that Khufu or his riches are

going to be crammed back there.

So, you don't believe this room was ever intended for

Khufu's burial? -No, I do not.

[Josh] And that leaves us one last chamber

inside the Great Pyramid,

closed to the public and not for the faint of heart.

[Mark] It's appropriately called the Subterranean Chamber.

To go to that one, we have to go down deep into the bowels of

the bedrock, 90 feet under the surface of the plateau.

Oh, boy.

We head back through the horizontal passage and then

down to the junction where the Robber's Tunnel meets

the Descending Passage below the original entrance.

That Descending Passage, it turns out, continues to

descend into the darkness.

And so we go down.

-Hey, Mark. -[Mark] Yeah?

This kind of sucks.

And soon we find ourselves within the earth itself.

[Mark] We're now in bedrock.

We're not in a passage built of blocks.

Essentially, it's a tunnel cut right through the living rock.

So we're not even in the building anymore?

-We're underneath the pyramid. -That's right.

So the entire weight of the Great Pyramid of Giza is

above our heads right now? -I'm afraid so, Josh.

And there's no alternative escape route.

Boy, you're really a ray of sunshine, you know that?

-It gets better and better. -Come on.

Oh, my word.

We are now in a tunnel carved directly into the bedrock by

Khufu's engineers, a passage that extends

for a whopping 344 feet.

There is one narrow shortcut here that links this tunnel to

the Grand Gallery above. It's called the Well Shaft.

It was perhaps to provide ventilation during construction

or an escape tunnel for the builders.

Either sounds good to me right about now.

OK, I'm at the bottom here.

The way forward is even narrower, but at the end of

this crawl, is something amazing.

OK. Well, I've come this far.

[Mark] Yeah, let's do it.

OK, almost there.

And it opens up into something.

Oh, what the hell is this?

-[Mark] What do you think, Josh? -What is this place?

-This is different. -Yeah, to put it mildly.

Deep beneath the Giza Plateau, I've been granted rare

and special access to a subterranean chamber that may

hold the key to the last resting place

of the pharaoh Khufu,

as well as the mysteries of his pyramid.

This isn't just different.

This is another world down here.

Well, you know, it literally is another world.

It -- this chamber, they were hollowing out of the bedrock,

the living rock, 90 feet below the original plateau surface.

So 90 feet under the plateau. I mean, look where we are.

This room is, without a doubt, the most bizarre feature

of the pyramid.

It is rough hewn and unfinished and feels like

a pitch-black primordial cave.

And recently, the internet was set ablaze when an Italian team

using radar data claimed there's even more down here,

specifically massive column-like structures

that some have likened to an engine or power source.

But the only thing beneath this room is a hand-dug ancient pit.

And that's just a dead end shaft there.

It's a dead end shaft.

It doesn't align with the chamber.

It's actually diagonal to the chamber, but it's almost

like a probe.

[Josh] And that probe went down only 10 feet

before the ancient Egyptians stopped.

In the 1830s, archaeologists dug down another

30 feet and found nothing, no kooky columns.

We're in a clearly unfinished room that was carved

with huge difficulty out of otherwise solid bedrock.

In fact, the technology used in the Italian team's claim

is considered unreliable.

None of the findings have been peer-reviewed,

and every credible archaeologist

has dismissed it as fantasy.

So that case is firmly closed.

Now, I just need Mark to explain one thing.

All right, so, what the hell is this room for?

I don't know. Really nobody knows.

One idea is this was where he was originally going to be

buried, and he wanted to be buried deep under his pyramid.

[Josh] We can see signs of the workers stations

and even their chisel marks.

But what's chilling is that for some reason the workers here on

one particular day simply walked away.

This whole unfinished chamber, leaving us kind of

a frozen moment in their work,

instills in me the sense that there were -- there was

a dark side to pyramid building.

[Josh] Hollowing out this space would have been grueling, deadly work.

performed deep beneath the earth

in nearly pitch-black conditions.

So why did they throw in the towel?

Well, perhaps it's because Khufu died mid-project

or that he changed his mind about where in the building

he wanted to be interred.

So instead of looking down,

perhaps we should be looking up.

OK, so have we now traversed every tunnel,

every chamber of the Great Pyramid?

We've been everywhere that you can go.

But could there be other chambers

inside the Great Pyramid?

You know, Josh, there was a time when I would have said,

"That's doubtful."

-But now I'm not so sure. -Really?

Yeah, because of recent discoveries by a project

called ScanPyramids.

[Josh] The group is made up of a team of highly-respected experts

from Egypt, as well as France, Japan, Germany,

Switzerland, the U.S. and Canada.

In 2016, they used cutting-edge detectors to measure naturally

occurring subatomic particles called muons

and how they're absorbed or scattered

when they hit the dense pyramid.

And the team detected something shocking -- two possible voids.

The first is supposedly behind the chevron blocks above

the main entrance, but many experts had

real doubts that something was there.

That is, until recently, when they inserted

a six-millimeter wide endoscopic camera between the blocks

and, voila, proved there was a small empty corridor there.

But it's the second void that has Egyptologists salivating.

High above the Grand Gallery they claim to have found

something even bigger --

an open space a hundred feet long

and 20 feet high similar in profile to the gallery itself.

It could be a hidden burial chamber or nothing at all.

So now what?

I mean, this is one of the Seven Wonders of the World.

They're not gonna start blasting blocks off

the side of the pyramid.

No, my Egyptian colleagues would never allow that,

but there may be non-invasive ways of investigating

the interior, and we may have a way of understanding

the interior of the pyramid with something we're scanning

on the outside. -Can I see it?

Yeah, it's happening right now.

[Josh] To figure out if there might be a bus-sized chamber

high up inside the pyramid, we climb back to the surface.

And Mark leads me a few hundred feet away to one

of his colleagues, who also happens to be

an old friend.

-Soren. -Oh, hi.

-[Mark] Hey Josh, I think you know this guy. -I sure do.

-What's going on, Soren? -Hi, Josh.

Great to see you.

Dr. Soren Michael Sindbaek is an accomplished archaeologist

whom I assisted on the hunt for the tomb

of the Viking king, Harald Bluetooth.

You're in the wrong civilization here.

Shouldn't you be at a Viking site?

Well, you know, archaeology is a very small world.

And I met Mark at a conference, and we realized that the tech

we'd been using in our Viking dig in Denmark

was just perfect for what was going on here.

-[Mark] Scanning. -[Josh] Scanning?

Scanning something really unusual.

-Come take a look. -[Soren] Watch your steps.

[Josh] This is wild. Look at this place.

What is this?

Located in the shadow of the east side

of the Great Pyramid, this strange set of open-air tunnels

was dug by the builders of the Great Pyramid at the time

of its construction. -[Mark] It's kind of an oddity.

-It's weird. -[Josh] OK.

[Mark] Does it look familiar?

Does this look familiar?

-Well... -Yeah, think about it. Think where we just were.

It certainly does look a little bit like it could be

a pyramid passage.

Well, there's a passage, but look what you're standing

and what we're standing on.

This is like the beginning of the Grand Gallery.

-Wait a minute, you're right. -[Mark] The bottom, the bottom.

This is the bottom of the Grand Gallery.

These are the exact same kind of benches

we were standing on. -[Mark] Yeah.

And there's that same ramp,

and that would go to the Queen's Chamber.

That would go to the Queen's Chamber.

But it's like a duplicate.

[Mark] Egyptologists so far think

it's a model of the passages in the pyramid.

This may be the world's earliest scale model.

Yes, that. The world's first scale model.

And if it is an accurate model,

then it's also a kind of map. -Right.

And that map may have clues to secrets about what's going on

inside the pyramid.

[Josh] For instance, a hidden void or chamber.

Remember in "Raiders" that scale model of the Egyptian city

of Tanis that led Indy to the Lost Ark?

I'm just saying, it worked for him.

So how do we prove that?

That's where we need a really detailed 3D scan to

compare and see whether it lines up.

Right -- is it truly a match or just a rough approximation?

-[Mark] Exactly, yeah. -That's what we need to figure out.

-That's what we need. -OK, so should we scan?

[Soren] Let's do it.

[Josh] It's a tight squeeze, so Mark stays back

while Soren and I enter with the 3D scanner.

This area is off-limits to the public

and has never been digitally mapped.

This is just like being inside the pyramid.

It's incredible.

[Soren] Oh, isn't it? Oh, look.

So we've got an intersection here?

[Soren] Yeah, just like between the Ascending

and the Descending Passages.

-And look, there's even a little lip here... -[Josh] Right.

...that would have stopped moving blocks.

[Josh] If this was a model for the network of tunnels inside

the Great Pyramid, then it appears to copy this critical

intersection where massive granite plugs slid into place,

sealing the Ascending Passage.

So if they were sliding those granite blocks down here that might have been

the stopper. -They would have stopped right here, yeah.

And does this continue down?

Yeah. And there's another passage.

Let's go down.

OK.

So, look at this.

This actually goes down, just like the Descending Passage

in the Great Pyramid -- that's insane.

So, start scanning here.

Yeah, I think this is a great spot.

We can see all the passages right here.

[Josh] To learn if this intersection of tunnels

truly mirrors those in the Great Pyramid,

or reveals something previously unknown,

we initiate our high-tech investigation.

-OK, so let's fire it up. -Yeah.

[Josh] The scanner activates, sending out laser pulses that

capture nearly 700,000 position points per second,

accurate to the fraction of a millimeter.

These measurements are stitched together with video shot

by multiple HD cameras, producing an exact 3D rendering.

OK, so scan complete?

-[Soren] Yeah, all done. -May I?

[Soren] Look here.

That is incredible! Look at that!

Look at that! That's amazing!

So let's say your granddad is Sneferu, the guy who basically

invents pyramid construction, even if one of his attempts is

a little, well, bent.

And your father is Khufu, the guy who builds this,

the Great Pyramid, tallest structure on Earth for

nearly 4,000 years -- tough act to follow.

So how do you make your mark?

Well, if you're Khufu's son Khafre, you build this.

The Great Sphinx.

240 feet long, 66 feet tall, carved out of the solid bedrock.

And most scholars agree that that is the face of Khafre,

which means this is basically the world's first selfie.

Take that, Dad!

That is incredible.

We've got our intersection here,

got our Descending Passage,

and we've got the intersection here going to

the Ascending Passage that goes up to the Grand Gallery.

I'm working with archaeologist Soren Sindbeck to scan these

so-called trial passages to confirm the theory that

they were built as an identical model

for the nearby Great Pyramid.

OK, so we need to scan deeper, I think, as well, yeah?

Yeah, but once we have the data,

we can actually see if it matches.

Right, and see if there's anything in here

that we don't know about in there. -Exactly.

[Josh] We deploy our equipment and initiate the full scan.

-You ready? -I'm ready.

One, two, three, go!

[Josh] Invisible lasers sweep every millimeter of the tunnel walls.

All right, scan's complete. Let's go do the next one.

We then reposition the device and scan again.

And again, collecting millions of data points.

Once the full survey is done,

we finally return to the surface.

OK, now what?

We need a few days to process it.

Once we've done that, we can go and compare it to

the Great Pyramid. -Amazing!

Here we go. I got the scanner.

Let's do it.

Once the data is processed, we'll take the digital replica

inside the Great Pyramid and use augmented reality

software to compare how the passages match

and how they deviate.

But while we wait for answers, I'm on to a new mission,

and it's as big as the pyramid itself.

Specifically, the two-plus million limestone blocks,

each weighing two to three tons, that make up

this iconic structure.

How is it possible that the ancient Egyptians were able

to carve, haul, and somehow lift them as high

as 450 feet into the sky?

It's a puzzle that has many people seeing ancient aliens,

but I've just gotten word about an excavation

that may have the real answers.

Curiously, it's located far from the pyramid,

on the shores of the Red Sea.

When you think about bodies of water that made Egypt into

the greatest empire in the ancient world,

well, it's all about the Nile, longest river on the planet

that turned Egypt into a farming powerhouse.

The Red Sea, on the other hand, is saltier than most oceans.

Quite simply, nothing grows here.

So what does this lifeless desert have to do with one of

mankind's most soaring achievements,

the Great Pyramid? Well, I have no idea.

150 hot and dusty miles later, and I approach the Saharan site

known as Wadi Al-Jarf.

Arriving at a gorgeous beach on Moses' favorite shortcut,

where I'm greeted by archaeologist,

Dr. Mohamed Abd El-Maguid.

-Hello. -[Mark] Hello.

Nice to meet you. I'm Josh.

Nice to meet you, too. I'm Mohamed.

Welcome to Wadi Al-Jarf.

Thank you. Happy to be here.

OK, what do I need to know about Wadi Al-Jarf?

First of all, what site? I don't see a site.

-The site is right there. -In the water?

Underwater.

The secret to the pyramids is underwater?

-Absolutely. -I'm intrigued.

-Let's go and see. -Show me.

Come on.

Fortunately, I always bring my dive gear to the desert

so I can put on a wetsuit in 110-degree heat.

[Josh and Mohamed speaking]

[Josh] Coming up on an all-new season of "Expedition Unknown."

OK, here we go!

I'm cracking the mysteries of

the Pyramid of Giza the hard way.

Oh! It's working!

And what we discover could rewrite history.

Are we looking at a lost passage in the Great Pyramid?

And later, a search for a Gold Rush fortune

with a "Gold Rush" guest star, Parker Schnabel.

[Parker] That's a good chunk.

The student has become the teacher!

Plus, I live out my childhood dreams

on the 40th anniversary of "The Goonies."

Hey, you guys!

Where a real-life treasure hunt could lead

to pirate riches.

-This is a piece of a Spanish galleon! -[man] Yeah.

[Josh] From a frigid dive for a top-secret Nazi sub...

That is an unexploded sea mine.

...to the sweltering jungles of Nicaragua.

This is tough going.

It's the adventure of a lifetime.

So what are we waiting for?