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00:04Of the seven wonders of the ancient world, it is the only one which is still standing.
00:08The Pyramid of Khufu in Egypt is an iconic monument which has captivated the world for
00:124,500 years. More than 10 million tourists come to touch its limestone blocks each year.
00:18It represents the pinnacle and perfection of building giant pyramids.
00:26It conjures such fascination because the methods of its construction remain unexplained even today.
00:32The right angles are accurate to within one-fifteenth of a degree.
00:35Can we do it today? I said no. No way. The Pyramid in the time of Khufu was a national
00:42project of the whole nation.
00:45How did the ancient Egyptians erect such a monolith without modern knowledge of civil engineering
00:49and above all, without any machines?
00:54The Pyramid of Khufu is a monument that breaks all the records, the highest pyramid ever built
00:59and the one with the largest volume.
01:02For three centuries, archaeologists and scientists have tried to solve the enigma of the Pyramid of Khufu.
01:08Today, innovative techniques have allowed Egyptology to make a leap forward.
01:12Among these techniques is photogrammetry. With its great precision, it enables a near-surgical analysis of the pyramids.
01:19And for the first time, I can really see the stones, the angle, clearly.
01:26The chromatic maps can help us to reveal many secrets.
01:30I would encourage all of you, do not wait. Go out today and buy the photogrammetry.
01:36Other Egyptologists believe the key to decoding the mysteries of Khufu lies in moving away from the pyramid
01:41and probing the surrounding area. That was how, in 2013, a French archaeologist made an historic discovery.
01:49These are the world's oldest known papyrus scrolls.
01:52Thanks to the latest digital techniques, we are going to try and solve the last mysteries of the Pyramid of
01:57Khufu.
01:58To help us, we have three of the world's leading Egyptologists, one French, one American, and one Egyptian.
02:04We have obtained exclusive authorization to film from the air over the most wonderful sites of ancient Egypt
02:10and carry out digitization on an unprecedented scale.
02:144,500 years after its construction, Khufu might finally reveal its secrets.
02:20I still believe that the burial chamber of Khufu is still hidden inside the pyramid.
02:27Welcome to Archaeology 2.0.
02:59Archaeology 2.0.
03:21Cairo, Egypt, a megalopolis of 20 million inhabitants which stretches for around 100 kilometers to the edge of the desert.
03:29It is here, behind these last buildings, that the mysteries of ancient Egypt begin.
03:34More than 4,000 years ago, it was here on the Giza Plateau that the pharaohs built pyramids as part
03:40of their quest for eternal life.
03:45Mark Lenner is an archaeologist.
03:47He has been visiting the Giza Plateau for decades, and each time, he feels the same sense of wonder.
03:56It feels amazing to be here.
03:59You know, I've been doing this for 40 years, and yet, every now and then I stop and I look
04:04up, and it's as fresh as it ever was.
04:07And the amazement is, how did they do this?
04:11How did they get people to do this?
04:14And what does it mean?
04:16What does it mean for them?
04:17What does it mean for us?
04:20Before him lies a necropolis covering 300 hectares with three vast pyramids in a remarkable state of conservation.
04:27But the one everyone comes to see is the most colossal one, the Pyramid of Khufu.
04:31So we have here the Great Pyramid, perhaps the only surviving wonder of the seven wonders of the ancient world.
04:39It's the biggest building in the world until the turn of the 20th century.
04:43It covers 13.1 acres, 230 meters to a side.
04:48It rose more than 146 meters.
04:50It represents the pinnacle and perfection of building giant pyramids.
04:58The Pyramid of Khufu is a monument that breaks all the records.
05:01It is the highest pyramid ever built and the one with the largest volume.
05:06It's a truly exceptional building for its time, given that pyramids were built based on an accumulation of experience acquired
05:12over just one century.
05:14So it is quite extraordinary.
05:17Perhaps most surprising is that after four millennia, the structure has lost less than 10 meters in height, a genuine
05:24technical exploit for antiquity.
05:27Yet, building such an edifice without the technological resources we have today seems near impossible.
05:36When you look at it and you are not an Egyptologist, you can think that no one really can do
05:45it.
05:45It's true.
05:46If you try to do it today, you can't because you don't have the same dedication that the Egyptians had.
05:53The pyramid was a national project of the whole nation.
06:01It took 30 years and more than 100,000 workers to raise this vast structure,
06:06whose main purpose was to host the pharaoh's sumptuous tomb and to bring him closer to heaven to attain eternal
06:12life.
06:14It's the pharaoh's tomb, but at the same time, once inside, it's the place where the king is going to
06:19be resurrected.
06:21In Egyptian society at the time, people believed in life after death.
06:25The king was thought to be the representative, the son of God, who would be resuscitated.
06:30So it's not just the king's tomb, but also the place where he will return to life.
06:37Hundreds of years of study have yet to reveal the building techniques used by the Egyptians.
06:42The one certainty is that it would be almost impossible to rebuild an identical pyramid to Khufu's today.
06:52But revolutionary technology should at last throw fresh light on some aspects.
07:01Vincent and Jonathan have come from Paris to photograph and scan the pyramid from every angle.
07:06Using these photos, they can reconstruct a precise 3D model of the pyramids.
07:11This technique is called photogrammetry.
07:16The cameras are synchronized.
07:18They record images at regular intervals.
07:20And the principle is that they are triggered at the same time, but from different angles.
07:24They also have different lenses, some with a much wider angle than others.
07:28That way, we can cover the whole pyramid and produce a full 3D model.
07:34For Khufu's pyramid alone, the engineers have to take 15,000 photos.
07:40But to photograph the summit, it is impossible to climb right to the top of the pyramid.
07:44The crew decide to use another technique, the drone.
07:48It's very complicated for safety reasons and due to administrative authorization to climb to the top of the pyramids.
07:53So we're going to use a drone, which will allow us to go as high as we like to play
07:58with the camera angles.
07:59And then we can stitch together the drone data and the data from this little camera to make an overall
08:04model.
08:06This rare permission to fly over Giza Plateau by drone will result in models with a precision down to the
08:12nearest millimeter,
08:13which should help our understanding of the pyramids.
08:16I think this model will be very interesting for the scientists because it has unrivaled resolution.
08:21And it is hard to imagine anyone will get anything better in the next few years, at least with the
08:26current technology.
08:28You can't operate all year round or just when you want on the sites we study.
08:33There can be problems with access.
08:35The sites are often open to tourists.
08:36So there's often a lot of foot traffic.
08:39Some zones are totally inaccessible.
08:43Photogrammetry is also the only technique that allows a digital copy of the pyramid of Khufu to be kept in
08:48case it disappears one day.
08:51After two full days on the site photographing the monument, the images are sent to Paris.
08:57In a few days, the Egyptologist will be able to analyze Khufu with unprecedented precision.
09:03And for some, there is a big surprise in store.
09:08The first images taken by drone are already giving a fresh viewpoint of the setting in which the pyramid of
09:14Khufu was built.
09:15The choice of location was not down to chance and is part of a clear strategy.
09:224,500, maybe 600 years ago, it was very different.
09:28The valley floor was green and lush.
09:31The Nile River probably had a major branch flowing very close to the western side of the valley, close to
09:37the plateau.
09:38There were harbors and waterways, basins, coming in to the foot of the pyramids for the livery of materials and
09:47people and stone.
09:50Khufu's builders chose the Giza Plateau mainly because abundant limestone could be found there.
09:56To construct the immense pyramid the pharaoh wanted would require astronomic quantities.
10:02But at the time, this was not new.
10:04The pharaoh's tombs had been becoming more monumental over the previous decades.
10:09But to begin with, the pyramids did not look like the ones we are familiar with today.
10:16The first pharaohs built themselves tombs in the shape of mastabas.
10:20Mastaba in Arabic means bench, so those first tombs were in the shape of a bench.
10:24They were about eight meters high.
10:26And then from a certain point during the reign of Djoser, the Egyptians decided to adopt pyramidal forms to house
10:33the sepulchers.
10:35Egyptian kings built pyramids because they wanted something high, they wanted something monumental.
10:40And the easiest thing to do is to build a big pile.
10:43Around the world, if you want to build high, the first thing you do is build something pyramidal.
10:50A century before Khufu, the pharaoh Djoser had the visionary idea of piling up several mastabas like boxes,
10:57one on top of another, to build higher.
11:00Djoser didn't know it, but he'd just created the first pyramid,
11:03whose form would evolve into the smooth pyramids like Khufu's.
11:07A model of perfection driven by the pharaoh's obsession to always surpass himself.
11:12And yet the plans remain a genuine mystery.
11:16Ten days after the first photogrammetric readings, the 3D model of the pyramid is finally finished.
11:23Our Egyptologists agree to analyze it.
11:27It's amazing because you can see the recording of every stone.
11:33Then for the first time, I can really see the stones, the angle clearly.
11:40And this actually captured my heart.
11:42I haven't seen the Great Pyramid like this.
11:45And that's why these maps can help us to reveal many secrets.
11:49I would encourage all of you, do not wait.
11:52Go out today and buy the photogrammetry.
11:56And if there is one thing that has always intrigued scientists,
12:00it's that the Pyramid of Khufu apparently has perfect dimensions.
12:03This assertion is very difficult to verify on the ground.
12:06So the original baseline of the pyramid is gone with the masonry that's been removed.
12:13But the baseline once came somewhere around here to this brass plug put down as a survey marker.
12:21So the pyramid used to come until here.
12:24But you can see how much is missing due to stone robbing over the centuries.
12:30It took Egyptologists several decades to complete accurate on-site measurements of the edifice.
12:37But today, in one click, photogrammetry allows us to verify
12:41whether the base of the pyramid does indeed have perfect dimensions.
12:47We can measure the pyramid's diagonals.
12:49So here we've got about 313 meters.
12:53Let's measure the other diagonal.
12:56That confirms pretty much what we thought.
12:59We've got diagonals which are the same length,
13:02a right angle, and sides of the same dimension.
13:04It is indeed a square. Everything's fine.
13:07They didn't get it wrong.
13:09The first fact that photogrammetry confirms
13:12is that the base of the Pyramid of Khufu
13:14is a perfect square with totally precise right angles.
13:19The right angles are accurate to within 1 15th of a degree,
13:23which is really a tiny margin of error.
13:25At the base of the pyramid, the sides measure 230 meters on average.
13:29But we should note that this average varies by only 10 centimeters.
13:33In other words, between one side and another,
13:35there's a maximum difference of 10 centimeters.
13:38Egyptologists all agree.
13:40The base of the Khufu pyramid is perfect.
13:44But no one today knows how such precision was possible.
13:48One thing is sure.
13:49The base was not built by bringing in stones, as one might imagine,
13:53but was cut directly into the rock of the mountain
13:56to save time and save on raw materials.
13:59So here the floor is natural rock, where they've leveled it.
14:02And this is the natural rock as well.
14:05And so is this, and this step,
14:09and yet another step, all in the natural rock.
14:13Here, it's almost four meters high.
14:15That means they could not make their perfect square
14:19by measuring the diagonals
14:20because they couldn't measure up and over the bedrock.
14:24They basically wrapped the pyramid around this natural rock
14:28that they left sticking up, protruding in the core.
14:34To get around the obstacle formed by the rock base,
14:37some Egyptologists think the builders used a very simple technique.
14:42One theory that could explain these extremely accurate measurements
14:45is the use of knotted ropes,
14:47long ropes punctuated with knots that allow measurements to be taken.
14:51However, it's well known that over a distance of 230 meters,
14:54the accuracy of a rope is not that great.
14:59It would be hard to attain a tolerance
15:01of only 10 centimeters using that technique.
15:04In Mark Lennar's view,
15:05the explanation is even more astonishing.
15:08The Egyptians may well have adjusted the base
15:10over time during construction.
15:12It was only when they rose the pyramid
15:15up above the level of the bedrock hill
15:17that they could measure and control the square by the diagonals.
15:23But its perfect dimensions
15:24are not the most extraordinary feature of Khufu's pyramid.
15:28To really understand this fascinating structure,
15:31one has to take to the skies.
15:33We are at a height of more than 500 meters,
15:36and the exceptional feature of Khufu
15:37is not readily seen with the naked eye.
15:40The pyramid of Khufu is also oriented
15:43according to the four cardinal points,
15:45and once again the margin of error is minimal,
15:47just one-fifteenth of a degree,
15:49which is simply extraordinary for the era.
15:52Our photogrammetric readings confirm the incredible alignment of the pyramid
15:56with the points of the compass.
15:58How did the builders achieve such a feat?
16:01Among Egyptologists, there are two conflicting theories.
16:07One of these theories consists in tracking a star
16:10from when it rises over the horizon
16:12to when it sets.
16:14Then bisecting the trajectory
16:15will give you the true north.
16:18It's a plausible theory,
16:20but it's difficult to put into practice
16:21with that degree of accuracy.
16:25Another school of thought
16:26is that the Egyptians did not use stars,
16:28but the sun.
16:31And then they would somehow align the pyramid
16:33based on the shadows of the sun at the equinox.
16:36That's another idea.
16:39With a simple stick placed vertically in the ground,
16:42you just have to follow the movement of the sun
16:44to note each time it is
16:45at the extremity of the shadow cast by the stick.
16:48And so these extremities,
16:50once joined, notably during the equinox,
16:52allow you to determine the direction
16:53of one cardinal point.
16:57On these transparent images
16:59obtained using photogrammetry,
17:01one can distinguish the base of the pyramid of Khufu,
17:04which covers 53,000 square meters,
17:06the equivalent of seven soccer pitches.
17:09Once again, its construction has confounded scientists
17:12since they observe that its leveling
17:14is close to perfection.
17:15There is practically no difference in level.
17:17The foundations are perfectly flat.
17:23With sides 230 meters long,
17:26there's a maximum gradient of 2.1 centimeters,
17:29which is absolutely remarkable.
17:31It's barely perceptible.
17:34Today, high-tech instruments exist
17:36to produce level surfaces,
17:38but at the time,
17:39the Egyptians had to be inventive.
17:42There is the idea that they used water
17:44and banks of mud
17:46around the perimeter of the pyramid.
17:48You could somehow flood an enclosure,
17:50say, around the base of the pyramid with water,
17:52mark the level of the water
17:54as a reference line,
17:56then drain the water
17:57and cut the rock to a uniform depth
17:59below that water.
18:02The most likely theory
18:03is that the Egyptians built a channel
18:05around the base of the pyramid,
18:06which they then filled with water.
18:10The water would naturally show
18:12the same level around the pyramid.
18:15Once a perfect base was built,
18:17all that remained was to pile up
18:18the 2.6 million cubic meters of stone
18:21that makes up the pyramid.
18:26On this point,
18:28Egyptologists are unanimous.
18:30The stones were laid
18:31on top of each other horizontally.
18:34These blocks
18:35at the bottom of Khufu's pyramids
18:37are not only very large,
18:39but Khufu's builders
18:40are laying them horizontally.
18:43Older pyramids were built
18:45with stones laid at an angle
18:48down in towards the center of the pyramid.
18:50No more.
18:52Khufu's using big blocks
18:53and he's laying them
18:55with horizontal bedding.
18:57As you can see here,
18:59this, in fact,
19:00makes for a more stable base
19:03of the pyramid.
19:05By laying the blocks horizontally,
19:08Khufu was innovating,
19:09breaking away from the methods
19:10used until then.
19:12This superimposition
19:13is confirmed by the photogrammetry.
19:17Sadi Hawass has been studying
19:18the pyramids for 50 years.
19:21Today, the Egyptologist
19:22has returned to the site
19:23to explain one of the key features
19:25of Khufu's pyramid,
19:26its blocks of stone.
19:28I'm sitting on the stones
19:29of the pyramid.
19:30But actually,
19:31this area here
19:32may be the most important area
19:34in the pyramid
19:35that can give us
19:37a great understanding
19:39of the construction
19:40of the pyramid.
19:41And that is a very important point
19:44to show to us
19:45that they put above the base
19:48long stones,
19:50small stones,
19:51long stone,
19:52small stones.
19:54On the outside,
19:55the faces of the pyramid of Khufu
19:57show great irregularities
19:58because they are made of stacked blocks
20:00with different dimensions and shapes.
20:02This is also confirmed
20:04by a closer analysis
20:05of the photogrammetric data.
20:10I'm coming very, very close
20:12to the Khufu pyramid
20:14and, you know,
20:15you can actually see
20:16the irregularity of the masonry
20:17in any particular place.
20:20And even at the bottom,
20:22there are big,
20:24what, solution cavities
20:26like miniature caves
20:27in the limestone.
20:31However,
20:32when one looks closer,
20:34Khufu is not so perfect.
20:36There is a simple
20:37explanation for this.
20:39It's messier in the core
20:40because it's an economy
20:41of labor and material.
20:43It would be far more
20:44labor-intensive
20:45to cut really well-squared blocks
20:47and do very fine joinery
20:48for the whole mass
20:49of the pyramid.
20:50It's easier just to bring
20:52irregular blocks,
20:53different shapes,
20:55and just, you know,
20:56saves a lot of time cutting,
20:57saves a lot of time
20:58making good joins
20:59between blocks.
21:01The engineers save time
21:03by using more rough-hewn stone
21:04inside the pyramid,
21:05but the irregularity
21:07of the blocks
21:07made things more complicated
21:09in terms of logistics.
21:11If you have well-squared blocks
21:13and they're all the same size,
21:16your vehicle for carrying them up
21:18can be the same size.
21:20It's like brickwork.
21:22You know,
21:22our bricks,
21:23our brick buildings,
21:23we use bricks
21:24all the same size.
21:25They're modular.
21:26But when you don't have
21:27modular stones,
21:29you know,
21:30one sled,
21:30if they brought it up on sleds,
21:32doesn't fit all.
21:34That is perhaps
21:35the biggest enigma
21:36of Khufu,
21:37a mystery
21:38that all Egyptologists
21:39dream of solving.
21:41How were the millions
21:42of tons of stone
21:43required for the construction
21:44of the pyramid
21:45brought to the site?
21:48Paradoxically,
21:49the most revealing discovery
21:50on this question
21:51was made a long way
21:52from the Great Pyramid.
21:54In 2013,
21:56a French archaeological mission
21:58made history
21:59at a dig in Wadi Aljarf,
22:01some 300 kilometers
22:02from Giza.
22:08So here,
22:10between these blocks,
22:11there were found
22:12about 800 fragments
22:14of papyrus
22:15from this period.
22:16These papyrus
22:17were between
22:19bad state of conservation
22:20and medium state
22:22of conservation.
22:22This is an incredible discovery.
22:26It gives a lot
22:26of information
22:27on the construction
22:29of the pyramid.
22:31French Egyptologist
22:32Pierre Tallet
22:33was in charge
22:34of that mission.
22:37In 2013,
22:38we found a collection
22:39of archives
22:40which included
22:40about 20 or 30 scrolls,
22:42many of which
22:43were quite badly decomposed,
22:45but some were still
22:46in a relatively good state.
22:48What makes this
22:48very important
22:49and in a way unique
22:50is that these are
22:52the world's oldest
22:53known papyrus documents
22:54and they correspond
22:55to the last year
22:56of Khufu's reign.
22:59You don't get luck
23:00like that many times
23:02in your career.
23:03This is an amazing find.
23:05For me,
23:06it might be one
23:07of the most significant
23:08finds of my whole career,
23:09if not the most significant.
23:11It took Pierre Tallet
23:13several months
23:14to decipher
23:14the first pieces
23:15of this priceless treasure.
23:17His analysis reveals
23:19that this is a log
23:19written by someone
23:20called Merer,
23:21an inspector in charge
23:23of a team transporting stones
23:24to the pyramid site.
23:25So this is the first testimony
23:27on how the work
23:28was going there,
23:29especially for the
23:30transportation of stones,
23:32especially stones
23:33coming from Torah.
23:34These papyruses
23:35provide invaluable details
23:37on how the blocks
23:38were transported
23:39from the limestone quarries
23:40of Torah
23:41on the east bank
23:42of the Nile.
23:47We can see
23:47there are cycles
23:48which are usually
23:49four or five days
23:50during which the team
23:52will first drag the stones,
23:53pull the stones,
23:54load them onto boats
23:56and then transport them
23:57from Torah to Giza,
23:59a journey which
24:00would generally take
24:01one or two days
24:02on a boat
24:02loaded with stones.
24:05Merer's papyruses
24:06also tell us
24:07that the Egyptians
24:08used the periods
24:09when the Nile river
24:10was high
24:10to transport the blocks.
24:12We also learned
24:13that Khufu had
24:14canals dug
24:14to facilitate delivery,
24:16thereby creating
24:17a direct link
24:18from the Nile
24:18to the pyramid site.
24:21The ancient Egyptians
24:22cut a canal
24:24on the west side
24:25of the Nile
24:26and they cut
24:27canals
24:28from that big canal
24:30connected with harbors
24:31at Giza Plateau
24:32and they transported
24:34the stones
24:34from Torah
24:35and actually
24:36from Aswan,
24:38the granite
24:38and the alabaster
24:40from Hatnub
24:40through the Nile
24:42and the canal
24:43and the harbors
24:44at Giza Plateau.
24:45They dug artificial basins
24:47near Giza
24:48and these artificial basins
24:50were operated
24:51by the opening
24:52of a channel
24:52which fed them
24:53with water.
24:55One of these papyrus
24:56texts
24:56describes the opening
24:58of this system
24:59of artificial lakes.
25:02It describes a jetty
25:04at a place
25:05called the entrance
25:05to the lake of Khufu
25:09and they brought
25:11in a large team
25:11of workers
25:12to remove
25:13the piles
25:14on the jetty
25:14and presumably
25:15let the water
25:16into this artificial lake
25:18just when the river
25:19began to rise
25:20to a sufficient level.
25:25This ingenious
25:26artificial navigation
25:27system
25:28allowed boats
25:29to deliver the blocks
25:30to the foot of the pyramid.
25:31From Aswan
25:32these limestone blocks
25:34had covered
25:34more than 1,000 kilometers
25:35to reach Giza.
25:37Merer's papyruses
25:38have so far yielded
25:39few indications
25:40about the vessels
25:41the Egyptians used
25:42but they have allowed
25:43Egyptologists
25:44an insight
25:44into how they were loaded.
25:46The average weight
25:47of a block
25:48is 1.5 tons
25:49but when you consider
25:50how many there are
25:51in the pyramid of Khufu
25:53I've tried to work out
25:54the load
25:55that the boats
25:56may have carried
25:57at the time
25:57of the ancient empire.
25:59One might think
25:59they could have carried
26:00up to 70 tons
26:01between 35 and 70 tons.
26:04On that basis
26:05one can imagine
26:06maybe 30 or 40 blocks
26:07on each boat.
26:09In the coming years
26:10the papyruses
26:11from Waty-Aljauf
26:12will no doubt
26:13reveal more secrets.
26:14But one thing is clear
26:16Merer's job was done
26:17once the blocks
26:18were delivered
26:18to the Giza plateau.
26:20The stones
26:21were then handed over
26:21to another team.
26:25They used wood
26:26to make sleds
26:27on which they put
26:28the blocks.
26:28They were tied on
26:30and dragged.
26:31They didn't just use men
26:32they also used
26:34lots of animals.
26:35We have images
26:36on inscriptions
26:37and reliefs
26:38and on tombs
26:38of people pulling stones
26:40on sleds.
26:41Some are damping it down.
26:43They sprinkled water
26:44or milk
26:45which helps the sled
26:46to slide.
26:48This is where
26:49another great mystery
26:50surrounding the construction
26:51of the pyramids
26:52comes in.
26:53How did the builders
26:54manage to raise stone blocks
26:56weighing up to 7 tons
26:58with no modern machines
26:59and to a height
27:00of 147 meters
27:02especially
27:03since the Great Pyramid
27:05required an astronomic
27:06quantity of stones?
27:09The total volume
27:10of this pyramid
27:11is some 2.6 million
27:12cubic meters of stone
27:14which equates
27:15to some 5 or 6 million
27:16tons of stone.
27:196 million tons
27:20that's 6 times
27:22the weight
27:22of the Golden Gate Bridge
27:23in San Francisco
27:24or 545 times
27:27that of the Eiffel Tower.
27:29For years
27:30there have been
27:31many theories
27:31some more plausible
27:33than others
27:33about the kind of ramps
27:35that were used
27:35to raise the stones.
27:37Photogrammetry
27:38brings a new approach.
27:40Aerial images
27:41may allow us
27:41to distinguish traces
27:42that cannot be seen
27:43with the naked eye.
27:46photogrammetry
27:47allows us
27:47to clearly make out
27:48the vestiges
27:49of another ramp
27:50which was discovered
27:51a few decades ago
27:52and this ramp
27:53went to the cemetery
27:54east of the pyramid
27:54the area of the mastabas
27:56and the small pyramids.
27:59When you go past
28:00in a car
28:01you don't even realize
28:02there's a ramp here
28:03because there's a road
28:04and all this
28:05and you forget
28:05you don't even look there
28:07but now
28:07with this image
28:08from above
28:09you can clearly see
28:10it's a construction ramp.
28:12This ramp
28:13was much too small
28:14to bear the immense blocks
28:15used in the pyramid
28:16but in all other respects
28:18it's identical
28:19to the construction ramps
28:20which the Egyptians
28:21used then.
28:23This ramp
28:24consists of
28:25two parallel stone walls
28:27which were backfilled
28:28in the center
28:28by debris
28:30the waste
28:31from where the stones
28:32were cut.
28:34One can well imagine
28:35that the monumental ramp
28:37that may have been used
28:38to build the Great Pyramid
28:39was made the same way.
28:43The Egyptologists
28:44are in luck
28:45because on the Giza Plateau
28:47there is a spot
28:48where a ramp
28:49is still visible
28:50to the naked eye.
28:51Here
28:52Mark Lennar
28:52shows us
28:53the last fragment
28:54of a small ramp
28:55used to build
28:56a mastaba.
28:59This is actually
29:00an ancient ramp
29:01I'm at the top of it
29:02and the ramp
29:04of course
29:04went up much higher
29:05and it was
29:07partly taken down
29:09but remarkably
29:10the ancient builders
29:11just left it here
29:12and we think
29:14the pyramid ramps
29:15were constructed
29:16in a very similar way.
29:17You have revetment walls
29:19of broken stone
29:21and there was lots
29:22of broken stone
29:23from all the quarrying
29:24and then you fill in
29:25between the revetments
29:27with limestone debris
29:28chips and sand
29:30and gypsum.
29:33We now have a good idea
29:35how the Egyptians
29:35built their ramps
29:36but one major question
29:38remains unanswered.
29:40What shape
29:40was the great ramp
29:41used to build
29:42Khufu's pyramid?
29:43Scientists disagree
29:44on this point.
29:46Some think
29:46the Egyptians
29:47opted for a giant
29:48spiral ramp
29:49wrapping like a serpent
29:50all around the pyramid.
29:54The problem
29:55with a spiral ramp
29:56is firstly
29:57its huge volume
29:58at least equivalent
29:59to that of a pyramid.
30:01On top of that
30:01it would have meant
30:02a very laborious
30:03and long route
30:04to reach the summit
30:05of the pyramid
30:06as it neared completion.
30:07You could imagine
30:08it would take
30:08several kilometers
30:09to reach the top
30:10of this spiral ramp.
30:13Another possibility
30:14is a straight ramp
30:15to the top
30:16of the pyramid
30:16but this form
30:18poses other problems.
30:20We know
30:21where the quarry
30:22of Khufu is.
30:23It's about
30:23350 meters
30:24to the south
30:25but it's only
30:27350 meters away
30:28and so to go
30:29on a straight ramp
30:30from there
30:31up to the highest
30:31part of the pyramid
30:32it's too steep.
30:34So probably
30:34they went
30:35to the lowest
30:36one third
30:36of the pyramid
30:37when you have
30:38something like
30:3980% of the mass
30:40already completed.
30:41You see
30:42because pyramids
30:43the mass decreases
30:44and then
30:45they probably
30:45did a road bed
30:47on an envelope
30:49of debris
30:50and retaining walls
30:52that they
30:53put all around
30:54the pyramid
30:55with a road bed
30:56that spiraled
30:56upward
30:57on top.
30:59Some pieces
31:00of the puzzle
31:01are still missing
31:01but today
31:03we have many elements
31:04on the logistics
31:04of the site
31:05and the surroundings
31:06of the pyramid.
31:08Many think
31:09that Khufu
31:09still has secrets
31:10to yield
31:11notably on its
31:12internal structure.
31:14Unfortunately
31:14even the most
31:15advanced technologies
31:16cannot yet allow
31:17us to see
31:18through the blocks.
31:20Certain Egyptologists
31:21remain convinced
31:21there are still
31:22many things
31:23to discover
31:23inside the pyramid.
31:31We were granted
31:32exceptional access
31:33to carry out
31:34a photogrammetric scan
31:35of the interior
31:36of Khufu.
31:38This still doesn't
31:39allow us to see
31:39through the blocks
31:40but these ultra-precise
31:423D measurements
31:43may help us
31:44to identify
31:44new elements
31:45within the pyramid.
31:49The continual flow
31:50of tourists
31:51means our team
31:52only has a few minutes
31:53and very little room
31:54to take the thousands
31:55of photos necessary
31:56for the photogrammetry.
31:59But once put together
32:01this unprecedented model
32:02of the interior
32:03of the Great Pyramid
32:04may allow us
32:05a better understanding
32:06of what lies
32:07inside Khufu.
32:10Today
32:10one no longer
32:11enters the pyramid
32:12by the main entrance
32:13located at a height
32:14of 17 meters
32:15but by another entrance
32:17opened by robbers
32:18in the 11th century
32:19which is a few meters lower.
32:23they forced this tunnel
32:25through the blocks
32:28that were already
32:29put in place
32:32and they came
32:35this far
32:40but then
32:41then they turned
32:45and they actually found
32:46the original passage.
32:48As confirmed
32:50by the photogrammetric data
32:51from inside the pyramid
32:52the internal layout
32:54of Khufu
32:54is quite unusual.
32:56Up until then
32:56all pyramids
32:57had been built
32:58according to the same model.
33:00The burial chamber
33:01where the pharaoh's remains
33:03would be laid
33:03was always located
33:05at ground level.
33:06Here
33:06there is not one
33:07but three
33:08two of which
33:09are raised up.
33:14look at all the pyramids
33:15you have
33:16all these
33:17descending corridors
33:19but here
33:20Khufu dug
33:21the two chambers
33:22the second
33:23and the third
33:24within the pyramid.
33:27The lowest chamber
33:28is located
33:29around 30 meters
33:30below the pyramid.
33:32Egyptologists
33:33call it
33:33the subterranean chamber.
33:35To reach it
33:36one has to crawl
33:37through a tunnel
33:37105 meters long
33:39and barely
33:40one meter high.
33:46The amazing thing
33:47about the subterranean chamber
33:48is that it's unfinished
33:50so you can actually see
33:51exactly how they were
33:52organizing the work.
33:53They bashed away
33:55the stone
33:56with big hammer
33:57of harder rock
33:59like diorite
34:00or they used
34:01a pointed chisel
34:02and you can see
34:03the marks here
34:03the striations
34:04that they left
34:06by roughing
34:06the rock out
34:07but this is basically
34:09one person
34:10probably a man
34:11one person's allotment.
34:17No sarcophagus
34:18was found here
34:19and this mysterious
34:21underground chamber
34:22was never completed.
34:24Was it built first
34:25and then abandoned
34:26in favor of other chambers
34:28or was it built last
34:29and left unfinished
34:30due to lack of time?
34:33In Vassil Dobrev's view
34:35Khufu would not have
34:36left anything to chance.
34:39This chamber
34:40was built first
34:41before the pyramid itself.
34:43Khufu saw
34:44there was a mountain here
34:45and he wanted to know
34:46just how solid it was.
34:48Today we would carry out
34:48a scan to find out.
34:50Before building
34:51a nuclear power station
34:52we check what lies
34:54below it.
34:55Khufu carried out
34:55a test in the mountain
34:56to see if it could support
34:58the monument
34:59he planned to build.
35:02Vassil Dobrev believes
35:03that Khufu was seeking
35:04the best place
35:05in the pyramid
35:06to position his tomb.
35:08He thinks the subterranean
35:09cavity was abandoned
35:10in favor of a second chamber
35:1250 meters higher
35:14and at the heart
35:15of the pyramid.
35:16Today that space
35:17is known
35:18as the Queen's Chamber.
35:23It's quite a large space
35:24more than 5 meters
35:26it's quite wide
35:27and one can imagine
35:29that to begin with
35:29the pharaoh chose
35:31this space over here
35:32to the west
35:33to build his burial chamber.
35:34But something happened
35:36which changed this project
35:37and they moved on
35:39to something
35:39much more complicated
35:40and difficult to achieve.
35:45The Egyptologist
35:47thinks Khufu
35:47changed his mind again
35:49and had a third chamber built
35:51this time
35:5140 meters above the ground.
35:53The pharaoh did
35:54then
35:55make two failed attempts
35:56before finding
35:57the ideal position
35:58for his tomb
35:59which would explain
36:00why Khufu's burial complex
36:01had three chambers.
36:04This theory
36:05is shared
36:06by other Egyptologists
36:07which confirmed
36:08that changes
36:09in the plans
36:10during construction
36:11were quite frequent.
36:14From the first pyramid
36:15and through to later ones
36:16they always modified
36:17the plans
36:18in the course
36:19of construction.
36:20Mentalities changed
36:21beliefs changed
36:22techniques changed
36:23so they adapted.
36:24A reign can be a long time
36:26several decades
36:27so the pharaoh
36:28may have had
36:28different wishes
36:29between the start
36:30of his reign
36:30and the end of it.
36:35Archaeologist
36:36Mark Lennar
36:36does not agree.
36:38For him
36:39everything was planned
36:40from the start
36:41and the subterranean
36:42chamber
36:43was not the first
36:44but the last chamber
36:45to be built.
36:48It's as though
36:49the king
36:49or the king's men
36:51came down there
36:52you know
36:53at the end
36:53of this 105 meter tube
36:56and said
36:57you know what
36:58nah
36:58we got a different idea
37:00we're going to put
37:01the chamber higher up
37:02in the pyramid
37:02but I don't believe this
37:05I think all three chambers
37:06were planned together
37:07as part of an initial plan
37:09and it's the subterranean
37:11chamber
37:12that was the last thing
37:13being done
37:14and that's why
37:15it's left unfinished.
37:19One thing is sure
37:20the highest chamber
37:22known as the king's chamber
37:23is where the only sarcophagus
37:25was found
37:26inside the pyramid.
37:28Everything points
37:29to this being
37:29the place
37:30where Khufu
37:30was buried.
37:33After closer analysis
37:34of the inner structure
37:35of the pyramid
37:36Egyptologists
37:37realized
37:38that some impressive defenses
37:39protected access
37:40to this chamber
37:43and today
37:44thanks to photogrammetry
37:45they can move
37:46through the pyramid
37:47in a few clicks.
37:48The data confirms
37:49that this very elaborate system
37:51begins about 100 meters
37:53from the king's chamber
37:54at the point
37:55where the corridors
37:55which serve the chambers
37:56intersect.
37:58Vassil takes us
37:59to see this arrangement
38:00on the ground.
38:06Here, we're at the crossroads
38:08of the ascending corridor
38:09which goes up
38:10to the burial chamber.
38:14And it's very interesting
38:15to note
38:16that this corridor
38:17has been totally blocked
38:18by big blocks of granite.
38:21That's a first
38:21because usually
38:23when they wanted
38:23to block a corridor
38:24they used limestone
38:27whereas here
38:28they've used granite
38:30to block a corridor
38:30that goes up
38:31so we are already
38:33getting an idea
38:34of greater protection.
38:37Granite is a much
38:38harder stone
38:39than limestone.
38:40Thanks to photogrammetry
38:42we can clearly see
38:43three huge granite stones
38:45which are called
38:45plug blocks.
38:474,500 years ago
38:49these stones
38:50sealed off the entrance
38:51to the corridor
38:52which went up
38:53to the king's chamber.
38:55After this first
38:56line of defense
38:57to reach the king's chamber
38:59one has to take
39:00the ascending corridor.
39:01After about 40 meters
39:03one arrives
39:04in the famous
39:05grand gallery.
39:10We are inside
39:13one of the most
39:14spectacular
39:16structures
39:16that ever built
39:18inside any pyramid.
39:20You have to understand
39:21before that the pyramid
39:22was not only a tomb
39:24the pyramid
39:26was representing
39:27the power
39:28and the dignity
39:28of the king
39:29and therefore
39:30they have to show
39:31miracles
39:32miracles
39:32in architecture.
39:34The grand gallery
39:35is one
39:36of the miracles
39:37that we see
39:38inside a pyramid.
39:42This gem
39:43of architecture
39:44measures 8 meters
39:45in height
39:46and 47 meters
39:47in length.
39:48But despite
39:49its majestic appearance
39:50in fact
39:51its role
39:52is purely functional.
39:56The purpose
39:57of this grand gallery
39:59was to stock
39:59the granite plug blocks.
40:01This grand gallery
40:01is one element
40:02in a system
40:03of closure.
40:06Since the plug blocks
40:07are monumental
40:08they also had to build
40:09a vast gallery
40:10to accommodate them.
40:12When you have a corridor
40:14one meter wide
40:14it can be simply
40:15covered by lintels
40:17flat ceiling pieces.
40:18When you go beyond
40:19a meter
40:19you need to make
40:20a vaulted ceiling
40:21to prevent it collapsing.
40:22So this wider gallery
40:24necessitated
40:25the construction
40:25of a core belt vault
40:27to hold it up.
40:28Once again
40:29photogrammetry
40:30allows us
40:30to better understand
40:31the principle
40:32of corebelling.
40:34If we zoom in
40:35we can see
40:35that the base
40:36of each block
40:37comes in a little
40:38compared to the previous one
40:39by about 10 centimeters
40:41over 1, 2, 3, 4, 5, 6, 7 levels
40:44until it completely
40:45closes off the ceiling.
40:47In this method
40:48of construction
40:49the blocks
40:50are placed
40:50one on top
40:51of the other
40:52but with a slight overlap
40:53which enables it
40:54to cover
40:55a much wider space.
40:57the grand gallery
40:59ends at the entrance
41:00to the king's chamber
41:01but before reaching it
41:02one last obstacle
41:04must be passed
41:05a final line of defense
41:07that Egyptologists
41:08call
41:08the Porcullis
41:09anti-chamber.
41:10this is kind of like
41:11a primitive machine
41:14people think
41:15that there were big slabs
41:17of stone
41:17like these
41:18put into these slots
41:20the slots
41:22the slots are defined
41:22by these raised bars
41:23of stone
41:24they've been broken away
41:26but you can see
41:27where they were
41:28and in these slots
41:30these large granite slabs
41:32were Porcullis slabs
41:36from the other side
41:38of these slabs
41:39they could actually
41:40lower the Porcullis slabs
41:42boom, boom, boom
41:44and finally close
41:46the king's chamber
41:46and this was the second line
41:49of defense
41:50against anyone
41:51coming into the king's chamber
41:53which is just beyond us
41:54to rob the burial
41:56of the king.
41:58These three huge
41:59Porcullises
42:00each weighing several tons
42:01block the access
42:03to the king's chamber
42:04along with the plug blocks
42:06they made up
42:07a near impregnable
42:07protection system
42:09designed to deter
42:10grave robbers.
42:12You cannot imagine
42:13that all these people
42:14who did this miracle
42:16in the
42:16in the angle
42:18and the facade
42:19of the pyramid
42:20and all of this
42:21and they know
42:22that the first thing
42:25when the king is buried
42:27thieves will enter
42:28next day.
42:30And they had to think
42:31about protection
42:32they had to think
42:33about deceiving thieves
42:34and that's why
42:35the whole building
42:37and the whole idea
42:39of the king
42:40and his architect
42:41is hiding
42:42his burial chamber.
42:47It was paramount
42:48for the Egyptians
42:49that no one
42:49should find
42:50the king's tomb
42:51but more importantly
42:52to avoid it
42:53being plundered.
42:55It was very important
42:57that his mortal remains
42:58stay intact
43:00for the whole pyramid
43:02engine to work
43:03as a kind of
43:04big resurrection machine
43:05and everybody else
43:07the entire court
43:08and their resurrection
43:09depended on it
43:10so they didn't want
43:11anybody to come in here
43:12violate the burial
43:13and basically
43:15turn the switch off
43:16on this resurrection machine.
43:20Protecting their pharaoh's tomb
43:22was a way for the Egyptians
43:23to ensure their own passage
43:25to an eternal life.
43:30Today, scientists
43:32have carried out
43:32remarkable efforts
43:33to understand the mysteries
43:35of this 4,500 year old legacy.
43:39Nonetheless,
43:40many archaeologists think
43:42that the world's
43:43most famous pyramid
43:44has not yet revealed
43:45all its secrets
43:46and some even wonder
43:48if there is another
43:49still hidden chamber
43:50containing Khufu.
43:54I always think
43:56that this sarcophagus
43:58cannot be
44:01for Khufu.
44:02It's very small
44:03and that's why
44:04it always gives me
44:05the idea
44:06that Khufu's burial chamber
44:08is still inside
44:09the Great Pyramid.
44:10I don't think it's impossible
44:11that one day
44:12we will discover
44:13another room
44:14inside the Great Pyramid.
44:15I don't think it's probable
44:16at this point
44:17because the pyramid
44:19is mostly solid space
44:22and I don't think
44:23other rooms
44:23would make sense
44:24in terms of the overall
44:25passage chamber system.
44:28Today, we have a vast knowledge
44:30of the structure
44:31of Khufu's pyramid
44:32and photogrammetry
44:34has allowed us
44:34to confirm
44:35many theories
44:36about its workings
44:38but after more
44:39than four millennia
44:40other mysteries
44:41have yet to be unraveled
44:42notably
44:43on how the world's
44:44greatest pyramid
44:45was built.
44:49You will have
44:50many things
44:50to discover
44:51about how they made it
44:53in generations to come.
44:54We'll still be thinking
44:55about the Great Pyramid of Khufu
44:57and all the pyramids
44:58and the ancient Egyptians
45:00and it's important
45:02you know
45:03because the human career
45:04is moving faster
45:06and faster
45:06civilization is evolving
45:08so rapidly now
45:09and it's important
45:11to understand
45:11what happened
45:12in order for us
45:13to understand
45:13what is happening now.
45:15I'm always saying
45:17that we found
45:19until now
45:19in Egypt
45:2030%
45:21of our monuments
45:23and Giza Plateau
45:25is still hidden
45:27many treasures
45:28in it
45:29that can reveal
45:30the mystery
45:30of these pyramids
45:32and you never know
45:34when the sand of Egypt
45:35may hide
45:37of secrets.
45:38of these pyramids.
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