NARRATOR: The Great Pyramid.

One of the most studied ancient riddles on earth.

Yet, questions still remain.

There were tens of thousands of people here building the pyramids.

Where's their settlement?

NARRATOR: Six million tons of stone shaped and transported over 30 years to build an eternal tomb with a sacred purpose.

SALIMA IKRAM: In creating this magnificent monument, they were going to have access to the afterlife.

NARRATOR: Now, stunning new discoveries are revealing lost secrets about the structure.

MARK LEHNER: There's another void, and that void exists right through this granite wall.

NARRATOR: About those who created it...

They actually called themselves the elite.

NARRATOR: And about how their king mobilized a proud and willing nation.

IKRAM: Like the space program, there was a sense of national pride and achievement NARRATOR: To overcome monumental disasters... LEHNER: They're trying again and again and again until they get it right.

NARRATOR: And achieve the greatest feat of precision engineering of the ancient world.

GLEN DASH: It's perfectly level.

It's a remarkable achievement.

NARRATOR: This is how the Great Pyramid united a nation... that would become one of the greatest civilizations of antiquity.

LEHNER: I think not about how the Egyptians built the pyramid, I think more about how the pyramids built Egypt.

NARRATOR: "Decoding the Great Pyramid," right now, on "NOVA."

♪ ♪ NARRATOR: The ancient Egyptians left an indelible mark on human civilization-- building awe-inspiring monuments, temples, and tombs; demonstrating remarkably precise engineering, all to honor their pharaohs as living gods.

Many were crowning achievements of the Old Kingdom, the first great flowering of Egyptian art that began 4,500 years ago.

The pyramids of Giza stand as enduring and mysterious relics...

Massive structures raised to ensure the afterlives of three all-powerful pharaohs: Menkaure, Khafre... and Khufu, the pharaoh who built the oldest and the biggest pyramid of all, the Great Pyramid...

The last surviving wonder of the ancient world.

IKRAM: The Great Pyramid is a testament to ancient Egyptians' ingenuity, acumen, and technical and scientific prowess.

DASH: The Great Pyramid is absolutely elegant and marvelous, even by standards today.

NARRATOR: How did the Egyptians engineer this enormous monument with such extreme precision, using only the most basic of tools and brute human power?

(hammers chiseling) Who were the thousands of laborers who toiled for decades on this massive project?

And how did building the Great Pyramid transform ancient Egypt?

Now, after decades of intense research, experts have uncovered a wealth of new evidence about the construction of the Great Pyramid.

LEHNER: From archaeology, from ancient texts and even from understanding the engineering of the pyramid, the people of the pyramid are coming back to life for us.

NARRATOR: When it comes to telling the story of the pyramids, it's never been easy to separate fact from fantasy.

The silent enigma of the pyramids can be like a blank canvas, ready to accept the latest outlandish theory about its builders.

Such theories drew a young would-be archaeologist to Egypt in the 1970s.

LEHNER: I came with so-called New Age ideas about the pyramids, believing that they had something to say about the lost continent of Atlantis and so on.

And when I encountered bedrock reality at the Giza Plateau, it didn't add up to those ideas.

NARRATOR: Now, after four decades of investigation, Mark Lehner has become one of the world's leading authorities on the Giza Pyramids.

His work has focused on illuminating the lives of the workers.

From sifting through an ancient garbage dump... (inaudible conversation) ...to excavating a highly ordered city that housed the laborers.

He's found evidence of a massive effort that transformed the Old Kingdom.

LEHNER: I think not about how the Egyptians built the pyramid, I think more about how the pyramids built Egypt.

NARRATOR: The pharaoh Khufu ordered the construction of this engineering marvel as a monument and tomb for all eternity.

And yet, we know very little about the man himself.

IKRAM: This tiny statue is the image of the man who made one of the largest buildings of the ancient world.

It's extraordinary that someone who has left us the Great Pyramid, which is still standing nearly 5,000 years after it was built, we still don't have that much of the man himself.

NARRATOR: For thousands of years, the only record of how Khufu built the pyramid came from the world's first historian, Herodotus, who wrote a history of Egypt in around 450 B.C.

It describes Khufu as a wicked and selfish king.

Perhaps not a very reliable account, considering Khufu had been dead for 2,000 years.

Herodotus wrote about the Great Pyramid as, of course, who wouldn't?

Because he came here as a historian and a tourist.

He also, of course, like any good tourist, listened to what the various tour guides said, and some of them were not very complimentary about Khufu.

And they accused him of being a terrible, mean king.

NARRATOR: Herodotus's account provided Hollywood with a box-office-ready story: that Khufu brutally enslaved his laborers to build his grand monument.

♪ ♪ (hammering) Egyptologists like Mark Lehner believe this story is too simplistic.

But to reach a deeper understanding, Mark first had to shift his perspective.

I realized I had to turn my back to the pyramids to properly understand them, because to properly understand them, you need to know about the people who built them, their civilization, their society.

There were tens of thousands of people here building the pyramids.

Where's their settlement?

And that led us to look to the far south southeast.

NARRATOR: In the 1990s, Mark collaborated with renowned Egyptian archaeologist Zahi Hawass, on a remarkable discovery.

Just south of the Great Pyramid, and on the edge of modern day Cairo, they uncovered the footprint of an ancient lost city-- the remains of streets, barrack-like buildings, bakeries, storage facilities, even what looked like guard houses gradually emerged from the sand.

Pottery and other artifacts dated it to the Fourth Dynasty 45 centuries ago, the time the pyramids at Giza were built.

Mark estimates that long galleries resembling dormitories could have housed more than 2,000 people.

And they were just part of a much larger city that now lies under modern-day Cairo.

The whole thing looks like an early version of institutional buildings like our hospitals, schools, prisons.

NARRATOR: Mark has recently investigated a huge ancient Egyptian garbage pit on the edge of the lost city.

Is that the surface of Kromer's excavation?

NARRATOR: This garbage dump, originally excavated by Austrian archaeologist Karl Kromer, is now being intensively re-examined by Mark Lehner's team.

So here is the gravel that's left behind, even after we sieve.

Now most archaeological projects, I daresay, just throw this away, they're done with it.

But we couldn't do that, because we saw that it's full of information.

NARRATOR: It may appear to be just a pile of sand, but it has revealed unique insights into the everyday lives of the people who lived and worked on the Giza Plateau.

(indistinct chatter) LEHNER: We're getting quantities and quantities of pottery.

Even this clean sand is showing all this kind of material, the objects of everyday life.

♪ ♪ NARRATOR: Pottery and clay seals suggests that this debris comes from an earlier period of the lost city, dating back to the time that Khufu was building the Great Pyramid.

This vast collection of new finds from both the dump and years of excavations at the lost city is being processed at the team's labs, situated in the shadow of the pyramids.

CLAIRE MALLESON: In this storage space, we have all of the artifacts, all of the material culture that's come from the excavations.

And it is probably millions of items.

We've listed hundreds and thousands of flint tools, we have dozens and dozens of large stone pounders.

We have broken seal impressions from sealing and opening and closing boxes and doors.

We have metal-working waste from probably resharpening and reworking copper tools.

NARRATOR: Among the finds is evidence that some of the Great Pyramid's workers were highly skilled.

MALLESON: It takes a particular knowledge and skill to make a blade like this.

This may well have been used for scraping things.

It's also possibly used as a cutting tool.

So, there almost certainly would have been specialized workers providing tools for the workers who were building the pyramids.

So it's a complete network, everything fits together like this.

If you haven't got the craftsmen to create the tools to provide the people who are going to build the pyramids, the whole system falls apart.

NARRATOR: Other discoveries revealed there were thousands of bakeries, indicating the mass production of food.

MALLESON: We have bread molds, and this is the largest size we have, and this is part of the evidence that they're doing things on a really massive industrial scale, because this would have fed six or seven men, just the bread made in this one mold.

NARRATOR: Archaeologist Richard Redding estimates that enough cattle, sheep, and goats were regularly slaughtered to feed thousands, providing a diet much better than slave rations.

REDDING: So, they're getting a lot of food, but they're requiring, their bodies are requiring a lot of protein, they're working very hard.

They're moving rocks, they work from sunrise to sunset, and we estimate they were getting almost 300 grams a day, between 200 and 300 grams a day of meat, which is about, probably a Big Mac or a quarter pounder with cheese.

NARRATOR: It's a far cry from the vision in popular imagination of an army of unskilled, disposable, and malnourished slaves.

IKRAM: The public thinks that slaves made the pyramids, and it's very annoying because they were well looked after, because there's no point in having a workforce that can't work.

So really, it was in the interest of Khufu to have a happy, well-fed, well-organized, and healthy workforce.

NARRATOR: But if they weren't slaves, who were they?

Egyptologists believe there was a readily available workforce.

And they weren't all full-time builders.

Most were farmers, working the fertile banks of the River Nile.

LEHNER: They would plant in late November, December.

The crops would grow, and then just about when it started getting warm in the springtime, they would harvest.

(thunder crashes) NARRATOR: But for three to four months of the year, that rural activity had to stop.

Seasonal rains high up in the Ethiopian and Nubian highlands flowed into the branches of the Nile, swelling the river and swamping the surrounding farmland.

LEHNER: Every year, the annual Nile flood turned the Nile valley and the delta into one big lake.

NARRATOR: Normal agricultural life during the flood season became impossible.

IKRAM: So, for four months of the year, the land is flooded.

And what are your peasants going to do?

Probably they'd go down to the tavern and have a drink or two or more and start criticizing the government.

NARRATOR: The floods gave Khufu a predictable source of seasonal labor.

They get fed, they get cared for they get some payment.

They also feel involved, and there's a sense of national pride.

So in a way, building a pyramid is a smart move.

NARRATOR: The artifacts unearthed suggest that while many laborers took on heavy-lifting jobs, thousands more were involved in other ways.

We've got estimates that suggest that there were more people involved in raising the food to feed the pyramid builders than were here actually working on the pyramids.

So, the...

I think I've got an estimate of over 1,500 individuals directly involved in raising sheep, over another 500 directly involved in raising cattle.

That's 2,000 people.

You can add them to what... the feeding... the raising of wheat and barley to make the bread.

NARRATOR: Mark estimates that along the length of the Nile, over 20,000 people played a role in the supply chain that ended at the construction site on the Giza Plateau.

Building the Great Pyramid must have had a dramatic effect on these one-million-plus people living in the Nile valley at that time.

NARRATOR: Adjusting for population, it would be the equivalent of almost ten million modern-day Americans recruited to work on a single project.

IKRAM: I think that certainly there are state projects where people try to get this feeling, a sense of national pride and achievement.

So, you know when the U.S. had its space program, there was a sense of national pride and achievement, even if not every individual was involved in it.

NARRATOR: Mark Lehner believes the evidence that the workforce was well-organized, cared for, and skilled makes sense, considering the audacious scale and precision of the construction project.

But although the Great Pyramid is the biggest pyramid ever built, it wasn't the first.

It was based on 80 years of trial and error by Khufu's predecessors.

The first Egyptian pyramid was a stepped structure built by the architect Imhotep for the burial of the pharaoh Djoser around 2560 BC.

It consisted of six tiers, rising to almost 200 feet.

Then, around two decades later, came Khufu's father, the pharaoh Sneferu, his likeness now preserved in the Egyptian Museum in Cairo.

He launched a campaign of pyramid building on an unprecedented scale.

Sneferu was the most prodigious pyramid builder of all time.

NARRATOR: He built three great monuments, known as the Meidum Pyramid, the Bent Pyramid, and the Red Pyramid.

In building those three giant pyramids, he basically did all the research and development that led to the perfection of the Great Pyramid of Khufu at Giza.

NARRATOR: But as he began building the first true smooth-sided pyramid, Sneferu ran into trouble.

The Bent Pyramid is named after the abrupt bend in the angle of its sides.

They made the slope too steep, and the structure kept threatening to collapse.

So, twice, they changed their plan and reduced it to a safer angle.

They're trying again and again and again, they're doing successive drafts until they get it right.

NARRATOR: The lessons learned during Sneferu's building campaign would eventually lead to the Great Pyramid.

IKRAM: Khufu took what Snefru did to the next level, but certainly without Snefru's work, Khufu would not have been able to achieve such a stupendous monument.

♪ ♪ NARRATOR: Everything about the Great Pyramid is exceptional.

Even by modern standards, it's an engineering phenomenon.

The precision of its planning began before a single stone was laid on site.

Its base is a near-perfect square, each side measuring 756 feet, covering an area the size of seven Manhattan blocks.

It's as tall as a modern 44-story building, and it weighs some six million tons.

DASH: When the tourists come here, inevitably they take a look at the Great Pyramid and they look up, and they look up with awe.

From an engineering point of view, when you come to a place like this, you look down.

Because the clues of how they built the pyramid are written in stone on a scale of acres here.

NARRATOR: Although it is 4,500 years old, it was built with astonishing accuracy.

At the base of the monument, engineer Glen Dash finds evidence that the foundations were meticulously prepared before construction began.

DASH: We're now standing on the bedrock, and originally, the bedrock sloped at a six-degree angle from the northwest to the southeast.

They carved all of that way.

NARRATOR: With only simple tools, the ancient engineers carved an almost perfectly level, flat foundation into the sloping Giza Plateau.

But that still wasn't good enough to build the perfect pyramid.

They would lay out on the bedrock a platform.

The platform itself is one of the miracles of the pyramids.

NARRATOR: Despite its unassuming appearance, this stone platform is one of the pyramid's most impressive and critical engineering marvels.

It's perfectly level over its entire periphery, almost a kilometer, to within plus or minus one inch.

That was one of the keys: the perfectly flat perfect platform to build the perfect pyramid.

NARRATOR: Dash's survey reveals that the base and sides of the pyramid are aligned to the north, south, east, and west to within a fraction of a degree.

But, in a time before the invention of the magnetic compass, how could the architects have laid out the square base of the pyramid accurately?

Glen has a theory.

You simply take a stick and you stick it in the ground.

The stick doesn't have to be straight, it doesn't have to be vertical.

You just have to do the test on either the spring or the fall equinox.

NARRATOR: The equinoxes are the two days each year that fall midway between midsummer and midwinter.

And ancient Egyptian sky watchers would have noticed that on those days, the sun rose and set directly east-west, casting a near-perfect west-east shadow line as it passed.

Glen argues that by marking the tip of that shadow as it moved-- with stones, for example-- the architects could lay out an accurate east-to-west line.

DASH: If you do that, you get the kind of accuracy that the Egyptians achieved when they aligned their pyramids, one tenth of one degree.

It's a remarkable achievement.

NARRATOR: But why put so much effort into aligning the pyramid so accurately?

Like every aspect of its design, the orientation of the pyramid had symbolic significance.

It mirrored the pharaoh's own supernatural alignment with the sun god Ra.

The afterlife of the pharaoh was modeled on the afterlife of the sun.

So, it was the similarity between the life cycle and resurrection of the sun and the life cycle and resurrection of the king that leads us to believe the pyramid was primarily a solar monument.

NARRATOR: The birth and death of the sun each day was at the heart of ancient Egyptian religion.

If burial rites were performed correctly, the sun and Osiris, the god of life, would merge with the king's soul to be reborn.

According to Egyptologist Salima Ikram, each evening, the sun and the king's soul traveled together to the underworld.

IKRAM: The ancient Egyptians believed that you lived forever.

Now, if you were a king, you had responsibilities, because you were not just a human being, you were a god, and as such you were son of the sun god, and you allied to the sun god.

And, of course, without the sun, the world doesn't function.

NARRATOR: The Great Pyramid and the king's tomb deep inside it was the starting point for the pharaoh's resurrection... ♪ ♪ (woman vocalizing) ...Reenacted each evening as the sun god and the king's soul disappeared below the western horizon and began their nightly journey through the underworld.

When the sun did battle against the forces of darkness and evil and Apophis, the king was with the sun god, almost fused with him.

♪ ♪ (woman vocalizing) The king went across the night sky battling against the demons of darkness... ♪ ♪ (woman vocalizing) ...and then had to emerge-- we hope-- victorious the next day... ♪ ♪ (woman vocalizing) so that Egypt would live, so that the land would flourish and that life would continue.

NARRATOR: The Great Pyramid was built to house and protect the king's precious mummified body during his eternal battle for the world's survival and prosperity.

Inside are three chambers joined to the outside by a network of passageways.

None of these internal structures were ever meant to be seen once the pyramid was complete.

Nevertheless, they are built with the same precision and attention to detail as the huge platform the pyramid sits on.

At the heart of the pyramid is a granite tomb where the dead king's mummified body would lie for eternity.

We're in the king's chamber-- more or less in the heart of the pyramid.

Here is essentially this great granite-lined box built, for the most part, to contain the body of the king.

NARRATOR: This chamber would be the starting point of the pharaoh's cycle of death and rebirth.

For Egypt's continued survival, this tomb needed to last forever.

So the engineers turned to one of the strongest stones available to them-- granite.

LEHNER: It must have made sense in a magical way-- what we would call magic.

There must above been spiritual power that made them take these choices.

NARRATOR: Building this magical chamber would pose an unprecedented challenge to the ancient engineers LEHNER: They didn't want the weight of the pyramid, the pyramid that was meant to protect the king and ensure his resurrection, so that the weight of the pyramid wouldn't actually crush and destroy his mummy.

Because if you destroy the mummy, the whole magical machine is broken.

♪ ♪ NARRATOR: But the ceiling of the king's chamber is flat-- a potential structural weak point.

All of the weight of the stone between this ceiling and the top of the pyramid would be bearing down on this flat surface with no support in the chamber below to hold it up.

Yet 4,500 years later, it is still intact.

How is that possible?

In 1837, a British antiquarian, Major General Howard Vyse, solved the puzzle by discovering what was above the granite slabs that formed the flat roof.

He actually put reeds through the cracks of the great beams and it went into dead space, empty space.

NARRATOR: What Vyse did next was highly destructive.

(explosion) So he had his workers blast their way up, making a vertical tunnel.

(explosion) NARRATOR: Vyse used gunpowder to blow a series of holes up through the heart of the pyramid and discovered not one hidden chamber, but a stack of five empty granite roofed spaces.

And at the very top: a large, sloping, gabled roof.

They used big limestone beams and they put them in a gabled pattern to, we think, so that the weight of the pyramid would be thrust away from this stack of chambers and from the king's chamber below.

♪ ♪ NARRATOR: The gabled roof on top of the secret stack of chambers relieved the downward stresses on the sacred tomb's flat roof and instead deflected the weight of the pyramid away from the king's chamber.

By today's standards, it may have been an excessively cautious solution, but they couldn't afford to take risks.

They were over-engineering, because they had never really done this before.

So that the pyramid, the very thing that was meant to protect the king and ensure his resurrection, would not collapse and crush his mortal remains.

♪ ♪ NARRATOR: Khufu's engineers had learned from the mistakes his father Sneferu had made.

And they pushed ancient architecture to the limit, turning the Great Pyramid into a unique monument.

LEHNER: Khufu was the first and the last to attempt this audacious engineering.

And so for that, the Great Pyramid-- although it's the classic pyramid in the popular imagination-- is actually the most unusual.

It's a huge anomaly.

♪ ♪ NARRATOR: Despite the unprecedented effort invested in Khufu's great pyramid, no records were ever found describing the details of this vast building operation... Until now.

In this barren landscape, archaeologists have discovered a unique written record.

But this isn't Giza-- it's over 150 miles away at a place called Wadi el-Jarf on the edge of the Red Sea.

♪ ♪ It's here that, in 2013, archaeologist Pierre Tallet was investigating the remains of the world's oldest port.

Dating to the Old Kingdom, it played a crucial role in the pharaohs' monumental building projects.

To cut massive stones, the builders needed high-quality metal tools.

The only metal readily available to the Egyptians was copper, which was mined in the Sinai, and ferried across the Red Sea to this port at Wadi el-Jarf.

Sinai is the main place where Egyptian were able to fetch copper at that time, and you... when you are building huge structures in limestone like pyramids, you dramatically need copper.

♪ ♪ NARRATOR: Pierre and his team began to excavate around the boat houses where ships were stored when not in use.

They then made a surprising discovery.

♪ ♪ First, we came across big limestone blocks.

It was inscribed with name of Khufu.

NARRATOR: It was an important find since so little evidence from Khufu's reign has survived.

But nothing prepared them for what they found next.

TALLET: It was a real surprise.

We have got small pieces of papyri.

NARRATOR: Pierre and his team had discovered a cache of fragile ancient documents on paper made from reeds called papyri covered in Egyptian hieroglyphs, including many examples of the same royal insignia... A cartouche-- an oval frame-- with the name of an ancient Egyptian pharaoh inside.

That name was Khufu.

TALLET: The cartouche of Khufu is quite everywhere.

NARRATOR: These are the world's oldest papyrus texts.

In 2017, Pierre Tallet published the first volume of his analysis of these ancient writings.

Amazingly, they offer the only first-hand record of the building of the Great Pyramid.

TALLET: You have the name of the Akhet-Khufu, "the Horizon of Khufu."

♪ ♪ NARRATOR: Akhet-Khufu, "the Horizon of Khufu."

In ancient Egypt, the word horizon can mean mountain of light, somewhere where the sun rises or sets.

And the Horizon of Khufu was the name the ancient Egyptians gave to the sacred Great Pyramid.

♪ ♪ TALLET: We have these words, I think, maybe more than 100 times.

We were excited-- it was, yeah, kind of a dream.

♪ ♪ NARRATOR: Dating to year 27 of Khufu's reign, the papyri lists details of the times, dates, and deliveries of cargo to the pyramid site.

Suddenly here are these Excel spread sheets of ancient times on papyrus, giving us accounts of what Khufu's workers received.

We have a diary and a log book-- that's what makes the Wadi el-Jarf papyri so much more significant.

NARRATOR: Among the entries are records of meetings with senior officials and the time it took to deliver a cargo.

There was even a note in red ink that someone had fetched a large supply of bread for the crew.

IKRAM: These papyri are fabulous because they give us the sort of slice of life, and it just gives you a sense that throughout Egypt there would have been these little hives of activity and people keeping the same kind of accounts, and by putting it all together you get a much bigger picture.

♪ ♪ NARRATOR: The papyri were written by the overseer of a work team that delivered the stone.

♪ ♪ A man whose name was Merer.

And Merer's handwritten notes record how he and his crew of 40 men sailed the Nile.

His was one of several ships delivering fine quality limestone to the construction site from the quarries of Turah, ten miles from Giza.

But how did they deliver the stones from the Nile to the site, over 100 feet higher on the Giza Plateau?

The papyri referred to artificial basins and harbors that Merer encountered as he approached the construction site.

When Merer and his team arrived in Giza, we have information about the artificial lakes that were made to allow boats to deliver raw materials for the building of the pyramids.

NARRATOR: Today, the Giza Plateau sits on the edge of modern-day Cairo.

Traces of the artificial basins recorded by Merer have been found underneath these streets.

(car horns honking) And thanks to the papyrus, we now know the ancient name of one of them.

♪ ♪ Ro-She Khufu-- the entrance to the Basin of Khufu.

When the Nile floods filled this manmade pool, a navigable path opened between the river and the Giza Plateau.

LEHNER: So we now know that the major influx of material-- both gigantic stones, timber, wood, grain to feed the people-- happened during the flood season when the Nile rose and covered the valley and filled the deep channel where it rose more than seven meters.

And they used this system of basins and waterways almost like a hydraulic lift to bring the materials needed for pyramid building.

♪ ♪ NARRATOR: If Giza was the beating heart of the pyramid project, then its lifeblood was the river Nile.

Its annual floods not only freed up a national work force but enabled the laborers to deliver supplies all the way to the foot of the pyramid site.

The Great Pyramid could not really have been built if Egypt did not have the Nile and a complex system of waterways connecting the land.

Because at this time, the terrain isn't good enough, we don't really do wheeled vehicles.

♪ ♪ NARRATOR: Remarkably, archaeologists at Giza have discovered the remains of two boats from the time the artificial waterfront at Giza was at its zenith.

One has already been carefully restored from the 1,200 pieces recovered by archaeologists, who believe that it was a ceremonial boat crafted to transport Khufu in his journey through the afterlife, while the second is now being meticulously excavated under the watchful eye of project consultant Mohamed Abd El-Meguid.

♪ ♪ MOHAMED ABD EL-MEGUID: Now they are extracting the woods of the second boat.

All of this will constitute the boat itself-- the hull, and the deck, and also the superstructure, which is the canopy itself.

♪ ♪ NARRATOR: These timbers provide a fascinating glimpse of ancient Egyptian boat-building methods.

♪ ♪ EL-MEGUID: The same techniques that we can see on the ceremonial boat were used for the transport boats that brought the stones from Turah to here or from Aswan to here.

♪ ♪ NARRATOR: Building the pyramids not only involved transporting thousands of stones up the Nile, but also required importing copper from the Sinai, which meant sailing across the Red Sea to the port at Wadi el-Jarf.

Mohamed believes these timbers reveal a cunning design feature that allowed Merer and others like him to use the same boat on bodies of water separated by 150 miles of desert.

EL-MEGUID: They would cut V-shaped channels in a 45-degree direction and the other one in the other direction, so he can pass through his ropes from one side to the other.

♪ ♪ NARRATOR: These holes weren't cut for wooden or metal fasteners because ancient Egyptian ships were held together with rope.

When we look at the Khufu boat, we see that here is a ship with elegance and amazing engineering but that's entirely stitched together with mortise and tenon joints and by ropes that interlace through all the parts of the hull, for example.

♪ ♪ NARRATOR: By using ropes instead of nails, teams could dismantle their boats and transport them across the desert to where they were next needed.

LEHNER: They took the parts from the Nile valley across to the Red Sea coast piece by piece.

Then they would put the parts together, they would basically stitch the whole ship together, sail across to Sinai, get their loads of copper, bring the copper back.

(hammering, indistinct chatter) NARRATOR: Copper is a relatively soft metal, prone to wearing down.

The amount of copper required for tools on the job site must have been tremendous.

But nothing compared to the hundreds of thousands of tons of stone demanded by the builders.

Meeting that need would have been a massive logistical challenge made even more difficult because the Great Pyramid is actually built of three different types of stone.

The exterior was an outer casing of high-quality white limestone concealing a much rougher inner core of coarse common limestone.

And then, deep within the pyramid, the complex of granite chambers reserved for the sacred tomb of the king.

And that meant millions of tons of stone had to be shipped to the site.

The rough limestone for the core came from a quarry just 500 yards south of the pyramid platform while the pyramid's high quality casing stones were brought by Merer's team and other work gangs from nearby Turah.

Meanwhile, the stone for the king's chamber had to be shipped from the major granite quarry in Egypt at Aswan, some 500 miles south of Giza.

These different types of stone all had to be delivered at around the same time because all the sections of the Great Pyramid were constructed simultaneously.

They built them in stages, incrementally and then filled in the mass of the pyramid around them, step by step, almost like 3D printing these days.

NARRATOR: All the elements of the pyramid-- the casing, the core and the internal chambers-- would rise as one from the Giza Plateau.

But as the pyramid grew, how did the builders manage to raise the blocks up the rising and sloping sides of the monument.

By looking at what seems to be in its loose state just rubble, we can have an understanding of how they built the pyramids because they formed this rubble into ramps and embankments, some of which like this one remain together until this day.

Probably they enveloped the entire pyramid with big embankments like this.

NARRATOR: But this was before ancient Egypt had the wheel.

Their solution was well-suited to the desert terrain.

IKRAM: It doesn't look very pretty, but it's really important because this is one of the key sort of tools that was used to make the Great Pyramid.

It is in fact a sledge and you can use them on sand as well as snow.

So, here we have this big sledge that would have been used to take the large rocks on them and pulled by teams of men up through the causeway, up the ramps to build the Great Pyramid.

♪ ♪ NARRATOR: For the people of Egypt, this backbreaking work was a physical investment in the spiritual future of Egypt, their contribution to ensure the pharaoh would be successful in his journey through the afterlife.

and they did it all with just the most basic of equipment.

♪ ♪ IKRAM: It's extraordinary to think that it was built with very simple tools.

You had wood rollers, you had rope, you had hard stone on soft stone, and you had a few metal tools, and, most importantly, you had the brains and the brawn of human beings.

And that's all that they had.

(indistinct shouting) NARRATOR: During the annual Nile flood, the construction site on the Giza Plateau would have received a constant supply of stone, food, and tools brought in by ships.

(indistinct shouting) It was an operation that would strain even a modern supply chain.

♪ ♪ The overseer of all the king's works had to keep in mind complex logistics and how to keep this whole workforce fed, healthy, and effective-- what modern contractors call the critical path.

How to get from the beginning point to the end point and deliver the product.

♪ ♪ NARRATOR: Merer's records give Egyptologists a unique insight into how this sophisticated operation worked.

♪ ♪ We were entering the administrative world of the people that were behind the whole construction of the monument like the Pyramid of Giza.

(hammers clanging) NARRATOR: The papyri also reveal the name of the man in charge.

That name was Ankh-haf.

And a stunningly lifelike image of him survives, now on display in the Boston Museum of Fine Arts.

Ankh-haf was a noble, the half brother of the pharaoh.

He seems to be, at that time, the vizier, which is the chief of the administration.

The big boss for the building of the pyramid of Khufu.

NARRATOR: Pierre believes Merer may have had several meetings with Ankh-haf.

And the papyri note that Merer's team was part of an "elite" perhaps because their cargoes of fine Turah limestone were highly prized.

Merer was responsible for bringing this limestone of Turah, which is of high quality needed to construct the... all the casing, outer casing of the pyramid of Khufu.

NARRATOR: The outer casing of Turah limestone gave the Great Pyramid a spectacular appearance.

Today the monument has been almost completely stripped of that outer casing.

But 4,500 years ago, the smooth white limestone delivered by people like Merer, would have covered the whole of the pyramid... ♪ ♪ (woman vocalizing) ...catching the rays of the rejuvenating sun in a spectacular display.

LEHNER: We can think of the Great Pyramid as a colossal special effect-- clad in white limestone, polished smooth.

But for them, such special effects were not entertainment, for them they were... they were religious, they were magical.

NARRATOR: The magic was a constant reminder of the special religious significance of the Great Pyramid and the dead king's fight for Egypt's survival.

For people like Merer, it was a privilege to be involved in the king's grand construction project.

LEHNER: They actually called themselves the elite.

Merer's group at one point was called in the papyri (speaking Ancient Egyptian language)-- "the chosen group."

♪ ♪ NARRATOR: It's estimated the people of Egypt spent some 30 years building the Great Pyramid.

Its last and most enduring mystery is that the mummy of the God King Khufu has never been found.

The granite coffin in the king's chamber is empty.

Many Egyptologists believe it was cleared out by tomb robbers in ancient times.

Others speculate that Khufu was never buried in his tomb at all.

If so, where might he be?

In 2017, scientists detected a mysterious void deep inside the Great Pyramid.

An advanced scanning technique called Muon tomography identified a large cavity the size of 747 fuselage approximately parallel with the king's chamber.

And that void exists right through this granite wall at about this level of the pyramid above the grand gallery leading to this chamber.

NARRATOR: Many theories for this mysterious empty space have been suggested.

It's possible this void, which is like a very vague cloud for us right now, is another chamber with untold treasures or, more importantly, documentation like the Wadi el-Jarf papyri.

But most likely it's dead space that they framed in to relieve the weight of the pyramid on the roof of the grand gallery just like the relieving chambers above the king's chamber.

NARRATOR: Further investigation may confirm the void is another example of the masterful engineering that's ensured this giant monument has stood the test of time.

But even without the pharaoh's body, the Great Pyramid continues to ensure Khufu's place in history.

IKRAM: Khufu in fact has achieved his immortality to a certain extent.

We might not have his body but his name lives forever.

And as each person recites it, he is once again given more empowerment in the afterlife, and his Great Pyramid does reign supreme.

♪ ♪ NARRATOR: Through Khufu's mighty building project, the people of ancient Egypt were drawn into the creation of a magical machine for the pharaoh's journey through the afterlife.

IKRAM: They were creating this magnificent monument which also gives you sort of religious credit because you're helping to build the house of eternity for your god king.

NARRATOR: The amazing discoveries of the Wadi el-Jarf papyri, the workers' city, and the preserved boats reveal the phenomenal planning operation that built the Great Pyramid and unified the people of Egypt into one of the world's first nation states.

The networks that they created and the national unity and infrastructure-- national infrastructure that they created for building these giant pyramids, that now was where they devoted their attention and their energies.

NARRATOR: The new evidence shows how Khufu's Great Pyramid project became the economic engine that drove the first great era of the ancient world's most vibrant civilization-- the Egypt of the Pharaohs.

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