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00:01Deep in the Egyptian desert there stands an exceptional structure, the Bent Pyramid,
00:06an enigmatic and unique edifice that has survived the centuries.
00:10It was the first building in the world to reach a height of over 100 meters.
00:16No one had ever built a pyramid of such gigantic dimensions.
00:20The pharaoh, to emphasize his power to his people, was building a very big structure.
00:25Anyone familiar with the famous pyramids at Giza
00:28immediately notices something different about this one.
00:32It's the only one on Earth that has this odd shape.
00:36This stone colossus was the work of one of the most powerful pharaohs in Egyptian history, Snefru.
00:43But the odd silhouette of his tomb may have been caused by an accident,
00:47the traces of which might still be visible on the inside.
00:50Major fissures started appearing in the structure. Everything was not well.
00:54I think Snefru sincerely wanted to build a true pyramid with straight sides.
00:59To uncover the secrets of the Bent Pyramid, we decided to look for answers at the very heart of its
01:04structure.
01:06Could its fascinating passageways provide us with clues?
01:09What secrets are its various chambers as enormous as cathedrals hiding?
01:14To shed light on all these mysteries, our scientists were granted permission to venture inside Egypt's most iconic pyramids
01:21with a latest generation laser scanner.
01:24It's quite tight in here. I'll try and warm my way through it.
01:29Using this procedure, they're able to create a very precise digital copy of the inside of the structure.
01:35With a few clicks, we can perform measurements that would be extremely hard to carry out on the ground.
01:40These tools will let our experts discover new clues in this ongoing scientific investigation which began 200 years ago.
02:22It's a one-hour drive up the Nile from Cairo to reach the southern limits of the necropolis of the
02:27pharaohs,
02:27a site that still today withholds a great many mysteries, the Dashur Plateau.
02:36This is where the Bent Pyramid takes center stage.
02:41For centuries, people have wondered about its enigmatic shape.
02:45But what exactly were the ancient Egyptians' intentions here?
02:50It's really hard to understand. It's very different from the others.
02:53Why was it made this way? Was it deliberate? Was it an accident?
02:58Does it have some ideological, religious meaning?
03:02So, the Bent Pyramid, in a way, is one of the most mysterious of all of Egypt's buildings.
03:09Frank Monnier is an engineer who specializes in ancient Egypt, one of the top experts regarding pyramid construction.
03:16He has long been fascinated by the puzzle of the Bent Pyramid.
03:21Having been closed to the public for decades, the structure has only been accessible for the last few years.
03:27This is Frank's first opportunity to go inside.
03:30I feel very emotional about finally being able to go into the heart of this pyramid.
03:34There's a lot of talk about the mystery of the Bent Pyramid and there are many problems still unsolved.
03:39But now, I'm finally going to be able to judge for myself what's inside.
03:44But even just getting inside is far from simple.
03:47You first have to climb 12 meters up the north face of the pyramid to reach the entrance, the height
03:53of a four-story building.
03:58From there, you plunge into the long descent, down a sloping 80-meter corridor, barely a meter high, which is
04:05particularly tricky to negotiate.
04:08Today, stairs help visitors descend this very steep corridor.
04:12But there was no such aid in the time of the pharaohs.
04:15General people, the great unwashed, like us tourists who go today, were not meant to go inside these things.
04:22So the faces of those sloping corridors would be smooth.
04:26So it would be really difficult without a rope or with some kind of handholds to get inside.
04:33At the bottom of the slope, you finally get to behold the pyramid's first chamber, known as the antechamber.
04:45What a marvel.
04:49A cathedral inside a pyramid.
04:53It's incredible that it goes so high.
04:56And it's in really excellent condition.
05:00Superb!
05:01Almost 4,600 years after it was built, the state of preservation of this chamber is quite spectacular.
05:08The walls are smooth, and the care taken over the joints between the blocks of stone is still clear to
05:13see.
05:13But the most impressive aspect of the chamber is its height.
05:17It's amazing to see a chamber go up so high.
05:20It's the highest chamber found in any pyramid.
05:24The height is over 17 meters. It's extraordinary.
05:26It's extraordinary.
05:29But how did the Egyptians manage to create such a grandiose space?
05:33What techniques did they use to reach such a height?
05:44The internal structure of the pyramid has intrigued Egyptologists for a very long time, and for a simple reason.
05:51It holds the key to the puzzle of its unusual appearance.
05:55The interior structure of the bent pyramid is as interesting as the exterior, because it actually has two entrances or
06:03exits, depending on how you look at it.
06:05And so there are two different ways of circulating.
06:09It was the first time they'd built successive chambers.
06:13The bent pyramid, when you look at later pyramids, does seem like a bit of an experiment.
06:20The interior and its complexity raises lots of questions.
06:24The complex arrangement of the various apartments is very unusual.
06:29Clearly, there must have been changes to the plan as it was being built.
06:36But what were the reasons for this?
06:38Why did the builders have to revise their plans?
06:40What challenges did they have to overcome?
06:43There are so many questions still awaiting an answer.
06:45The climatism of the pyramid was designed to help to get these peripherals.
06:46They are re-enさん jobs, and a little bit more.
06:51The cleaner and Egyptologist Frank Monnier knows the plans of the pyramid by heart.
07:02On this sheet of tracing paper, I've drawn the funeral apartments of the Bent Pyramid.
07:07Everything is represented here in one cross-section. The lower apartments accessed from the north
07:12entrance and the upper apartments accessed from the west entrance. It would be really
07:17interesting to use the laser to scan the antechamber of the lower apartments.
07:23To get a clearer insight, he's decided to undertake a new and unprecedented mission inside the
07:28pyramid. To this end, he's called on Alban Brice Pimpot, an archaeologist who specializes
07:39in digital imaging. He's going to use a lidar, a laser scanner, which records hundreds of
07:45thousands of measurements per second in 360 degrees.
07:53This high-performance equipment can make measurements of distance and volume of unparalleled precision.
08:04It's the first time this cutting-edge technology is being used on the Bent Pyramid.
08:13The entire interior of the structure will be scanned, even spaces never previously visited,
08:18with a totally unprecedented level of detail.
08:23My mission today is to scan the interior spaces of the Bent Pyramid, to try and document as
08:30much as possible, and collate all this detailed geometric information.
08:37The Bent Pyramid structure has two different inclinations, which we can probably get a sense
08:42of from the interior spaces, so it'll be interesting to document it with this scanner.
08:47This digital scanner is so miniaturized that it can be introduced into every part of the
08:52pyramid, but it could still be tricky in some of the tightest spots.
08:56In such narrow confines, it's always a bit delicate to do the digitization, because the changing
09:02angles can cause problems. They're tricky spaces to scan.
09:10After scanning the long sloping corridor, Alban Brice Pampo reaches the antechamber.
09:18In this large open space, he can deploy his scanner more easily.
09:23The results should shed light on how the Egyptians were able to create such a vast space in such
09:29ancient era, 4,600 years ago.
09:36The man behind this off-the-scale project was one of history's greatest builders, the pharaoh
09:41Sneferu.
09:51While his name isn't that well-known today, Sneferu was a true legend in the Egypt of the pharaohs.
09:59It was Sneferu who built the first great pyramids. He was an extremely well-known king in ancient
10:04Egypt, the very example of a pharaoh. There wasn't Khufu, it was Sneferu.
10:11In folk tales, he is called a beneficent king. So the image of him presented in later literature
10:18seems to be of a very sort of a jolly, very demotic kind of king.
10:24Sneferu founded the fourth dynasty, the most famous of ancient Egypt's dynasties. He was the
10:30father of Khufu, who lived in around 2600 BCE. This was the very heyday of the ancient empire,
10:37the golden era when the giant pyramids were built. Sneferu's reign was a long one,
10:43lasting quite probably 40 years, during which time the country underwent profound changes.
10:48Egypt was at the height of its power.
10:53Sneferu opened up a new era in Egyptian history. The world really did change under Sneferu.
10:59To have the economic resources and the resources in terms of personnel to carry this out,
11:06Egypt must have been in very good shape under Sneferu's reign.
11:17His rule was a time of power and prosperity. He was able to expand trade networks, develop the economy,
11:24improve administration. And all of those activities enabled him to have the resources and the bureaucracy
11:33to create his massive pyramids.
11:41After several weeks of digital analysis, the scan results are finally ready.
11:48They gave a very clear overview of the first chamber.
11:54Egyptologist Vassil Dobrev sees the images for the first time.
11:57What we often had before were cross-sections from which you couldn't get an idea of the three dimensions.
12:05Now we can move around in every direction and try to understand things.
12:11Studying this is a lot easier.
12:15The first observation is of the incredible technical nature of the chamber's architecture.
12:20The first thing I notice right away is that this is a perfectly corbelled construction.
12:26Each block is placed on the one below, with a 10 cm shift inwards so that it gradually closes.
12:32And this goes up for 17 meters.
12:35This technique of stacking the blocks like an upside-down staircase did not happen by chance.
12:40On the contrary, it shows the great ingenuity of Sneferu's architects.
12:45For the first time, they wanted to build actually inside a pyramid.
12:48So, to protect the funeral apartments, they had to innovate and invent a structure that would dissipate the forces.
12:53It's beautiful.
12:57Corbelling is a system of roofing a room.
13:01By gradually stepping in each course of masonry as you go up a slight distance.
13:08So eventually, the whole thing becomes almost like a triangle in steps going up to the roof.
13:14It seems to be an architectural innovation by engineers working for Sneferu.
13:18At the ceiling, the quality of the builder's work is quite remarkable.
13:23The corbelling we can see here in this antechamber is in an exceptional state of preservation.
13:28Just think, it's over 4,500 years old.
13:31There are about 104 meters of masonry all stacked up.
13:34Think about that, 104 meters of masonry.
13:37That means thousands of tons weighing down on this chamber,
13:39and the corbelled vault is still perfectly stable.
13:43While the antechamber would appear to be perfect,
13:45a closer look reveals that something isn't quite right.
13:52Sneferu's builders apparently encountered some problems during the construction.
13:56On this wall here, you can see some pretty serious cracks.
14:00It really looks like the block must have moved.
14:03The whole thing holds together.
14:05But there were small shifts in the structure,
14:08and you can see that this crack here was patched up and renovated quite recently.
14:14The restoration work, carried out so that the pyramid could be made accessible to the public,
14:19has to some extent concealed this extremely ancient fissure with cement.
14:26But the analysis done with the LIDAR scan provides a clearer view.
14:31The technology gives a negative image, which reveals details invisible to the naked eye.
14:37The scan clearly shows that there were some small movements, small cracks,
14:42which ended up creating gashes in the walls of the antechamber.
14:47Right here you can see a bit of a bulge, a very clear crack.
14:54As if some external pressure had pushed a section of the wall out of place.
14:58How do we explain this gash several meters high, right at the heart of the pyramid?
15:04Could these flaws inside the pyramid have been caused by the very way the building was designed?
15:11The answer could come from the context of its construction.
15:18It's hard to imagine, but this pyramid was in fact the second one that the pharaoh envisioned.
15:27Snefru started his pyramid building journey in Medum, and it initially began as a step pyramid.
15:35The Medum pyramid, 45 kilometers further south, was the first pyramid that Snefru had built.
15:41It looks particularly strange to us today.
15:46But it was originally planned as a step pyramid, like all those built up until that time in Egypt.
15:54Right up until Khufu's father suddenly decided to change things.
15:59Mark Lenner is one of the world's most famous authorities on pyramids.
16:04He's been studying them for 40 years and remains fascinated by the bent pyramid and the story of Snefru.
16:10He builds a giant step pyramid at Medum. This is important for understanding this monument.
16:17He starts it with six steps, then he enlarges it to seven steps, and then he stops.
16:23In about the 15th year of his reign, he came to Dashur to start the bent pyramid.
16:30But why move that immense workforce to start again from scratch on such a colossal building project?
16:36What drove the pharaoh to make this radical decision?
16:41I think Snefru sincerely wanted to build a true pyramid with straight sides.
16:46He did not want a step pyramid. That was no longer satisfactory for his burial place.
16:52So Snefru looked for a new place to start his brand new innovations.
16:59A true architectural revolution. The first true pyramid in human history. A perfect triangular shape.
17:07It seems that religious considerations may have been behind this idea.
17:12The switch seems to be from some kind of stairway to heaven to the idea of the king being buried
17:20under a petrified version of the sun's ray.
17:23This was the development of sun worship. Pyramid-shaped monuments were part of this equating of the monarchy with the
17:30sun.
17:30For him, it was merging himself and his burial place with the rays of the sun.
17:40Snefru's perfect pyramid, with its smooth sides, would reflect the sun and allow the pharaoh to ascend to heaven after
17:47his death,
17:47by which means he would be united with the sun god. He demanded of his architects a technical feat totally
17:55unheard of at that time.
17:59Only, as anyone can see, his plan did not work.
18:03At 47 meters from the ground, the inclination suddenly changes.
18:08So what happened?
18:14Looking for an answer, Frank Meunier retraces his steps, making his way back up the long slope.
18:21And it's now that he makes a surprising discovery.
18:2412 meters from the entrance, strange empty spaces are apparent on either side.
18:29These are particularly clear on the LIDAR scan.
18:34It's quite strange, because here we are, 12 meters from the entrance to the pyramid, and what do we find
18:40here?
18:41Features characteristic of the entrance to a pyramid.
18:43An outer wall, and these famous notches, which here have been filled in, but which would usually be found at
18:50the entrance,
18:52by here, and its counterpart here.
18:54These would have held a beam that would have helped workers get up and down.
19:00These notches were filled in during recent renovations.
19:05But they're usually found at the entrance to a pyramid.
19:08What is the explanation for their being here?
19:11Why are the features of an entrance found a good distance down the corridor?
19:16This is a very serious clue, allowing us to surmise that what was here, at this place,
19:21was the original entrance to the pyramid, as it was first built.
19:25The pyramid, as it was first built.
19:28In other words, another structure is hiding inside the current pyramid.
19:33It's a fascinating discovery.
19:35To find out more, Frank Meunier takes measurements of the wall.
19:38But it suffered the ravages of time, and isn't perfectly straight.
19:44I'm using an inclinometer, which lets me measure the angle of inclination of this wall, this side.
19:50So, if I position the inclinometer, it tells me that the wall is at an angle here of 62.74
19:59degrees.
19:59If we move it a bit, here we get about 62.
20:04What do we have here, about 58, 59?
20:06You see, it's not consistent, but as an average, it's not far off 60 degrees.
20:10So, this must be the wall of the pyramid as it was first built.
20:13A pyramid whose sides were intended to have a slope of about 60 degrees.
20:20A very different inclination from that of the sides of the pyramid we see today.
20:25Thanks to Frank Meunier's measurements, the pyramid hidden on the inside is now revealed to us.
20:31But what did it look like?
20:32Was it different from the one before our eyes today?
20:36According to the Egyptologists' calculations, it had a base that measured 157 meters along each side,
20:42making it the biggest ever built up until that time in Egypt.
20:47With its extremely steep sides, at 60 degrees, the pyramid's peak would have been at the phenomenal
20:53height of 136 meters, the same as a 40-store tower block, and twice as high as Djoser's pyramid,
20:59which was up until then the highest in the world.
21:05The pharaoh, to emphasize his power to his people whilst he was alive, was building a very big structure.
21:12He knew in the future it would be very difficult to remove that monument, so he would hopefully,
21:18through that, live forever.
21:19Sneferus said, I want a true pyramid, like the rays of sun.
21:23But nobody knew, should it be 43 degrees, should it be 50, should it be 60?
21:28He chose 60, a very steep slope.
21:30But they didn't know what a true pyramid looked like, how steep it should be.
21:34All the pyramids before, they were step pyramids, they weren't true pyramids.
21:41But then, when the entire interior of the pyramid was finished,
21:45the plans were suddenly changed, for a reason that still remains a mystery.
21:52Maybe, at some point, they realized they had to build a pyramid with 60-degree slopes,
21:56and to extend that to the summit using ramps, of whatever kind it might be,
22:00would be extremely difficult, it would require a huge amount of energy.
22:04I think they were having problems in the 60-degree pyramid, and that's why they lessened the slope,
22:09that's why they put a mantle about it. And everything suggests to me a change in plan
22:15as you build. Typical for ancient Egyptian builders.
22:20So the Faro's architects decided to modify their plans.
22:25A thick covering of masonry was now added to the four sides of the construction to consolidate it.
22:31The base increased in volume by 20 percent, with each side now over 189 meters long.
22:37This also considerably reduced the angle of the slope to 54 degrees.
22:44It must be because of this decision that the pyramid has the unusual shape we see today.
22:51Because this enlarging would have consequences that were unexpected and catastrophic.
22:57The Egyptians hadn't anticipated the different ways in which the outer covering
23:01and the inner core would behave. The higher up the covering was from its base,
23:06the more had settled, whereas the inner core remained constant with its characteristics unchanging.
23:13There were major fissures started appearing in the structure,
23:17and also blocks have fallen from above, all of which suggests that everything was not well.
23:27The immense quantity of masonry added by the Egyptians weighed far too heavily on the original
23:32pyramid. As more weight was added, the compression increased.
23:38The evidence of these problems is clear on the inside of the pyramid.
23:43In the sloping descent from the north entrance, there are impressive traces,
23:47particularly where the entrance to the original pyramid was.
23:51Wow, here we have entire slabs of rock, of stone, which have come detached and are ready to fall on
23:58us.
23:59It's pretty scary. Here we have a big crack, which gives you a view inside the guts of the construction,
24:06with thin slabs of rock that have come detached from the blocks, from these blocks here,
24:12and the next blocks, quite simply because the outer covering has slipped and slid,
24:17breaking off large lumps of rock. Sliding down the core of the pyramid,
24:24the added masonry caused major cracks throughout the edifice.
24:31We see them as well on the outer layer.
24:35You can see very substantial fissures cutting right through different courses of limestone.
24:42The biggest crack is right here. It's cracking and snapping, and they're trying to chisel it out and patch it
24:53as they go.
24:56Seeing all these fissures appearing, Sneferu's architects realized their mistake.
25:01The very structure of their perfect pyramid was in danger.
25:09They had come up with a solution, and quickly. They had to adapt before the building deteriorated further.
25:18And the builders had an idea that was as ingenious as it was simple to try to save their pyramid.
25:24The change from a proper straight-sided pyramid to the bent form is probably to do with an attempt to
25:32reduce the sheer amount of weight which was being placed on the side.
25:35They decided they needed to reduce the weight, reduce the slope, and so they went, oops, and reduced it to
25:4343 degrees.
25:46The Egyptians realized that by radically lessening the slope of the sides to an angle of 43 degrees, the building
25:52process would be a lot easier.
25:55Above all, they understood that this would reduce the mass weighing down on the foundations, thereby giving the edifice a
26:01firmer foothold.
26:03This was how Sneferu's pyramid, initially intended to have perfect triangular sides, ended up with its unusual shape.
26:11Proof of the ingenuity and amazing adaptability of the builders of the pyramids.
26:17They were adapting. They're working with things, they're meeting challenges, what we would call research and development.
26:23They're responding to challenges, and they're working everything out.
26:29Once finished, the pyramid reached a dizzying height of 104 meters, which is almost 10 meters higher than London's Big
26:36Ben.
26:38At the time, it was the tallest construction in the world.
26:42We've calculated that Sneferu's pyramid has around 1.3 million cubic meters of stone.
26:48That's about 3.3 million tons.
26:52It's quite something. No one had ever built a pyramid of such gigantic dimensions.
26:58Despite this feat, Khufu's father was not satisfied with the result.
27:04He decided that he wanted a straight-sided pyramid, and he was going to get it.
27:15So, the mighty pharaoh quite simply had a third pyramid made, the Red Pyramid, barely two kilometers from the Bent
27:21Pyramid.
27:25This time, the result was perfect.
27:30There, Sneferu succeeded in building, for the first time, a true straight-angled pyramid.
27:37The true pyramid that he had long wanted to achieve.
27:41Finally, there was a true pyramid representing the rays of the sun.
27:45When you look at it, it seems to be attempting to address all the lessons from the building of the
27:53Bent Pyramid.
27:57Sneferu's architects had finally succeeded and pulled off the incredible achievement of building the first straight-sided pyramid in human
28:04history.
28:08They'd learned from their mistakes making the Bent Pyramid.
28:13Taking no risks, right from the start, they decided on an angle of 43 degrees,
28:18the inclination at which they'd topped off the Bent Pyramid, and a guarantee of far greater stability.
28:34But some Egyptologists are not convinced by the theory of the design accident in the building of the Bent Pyramid.
28:42Among them is the archaeologist Vassil Dobrev, one of the top authorities on the ancient empire.
28:49He believes the edifice was intended, right from the start, to have this peculiar shape.
28:54The Egyptians wanted to imitate the primal hill in which Egypt was supposed to have been created.
28:59They believed that in the beginning, there was the primordial ocean.
29:03And out of this primordial ocean, there emerged the first hill, which they called Ben Ben,
29:08because it had two shapes like this. Ben, Ben. I think the Egyptians wanted to express this bursting
29:14out of the sea with this shape. So the shape was totally intentional.
29:23Maybe this was an experiment, actually, to get to this obelisk shape that was intended all along.
29:30Ben Ben was, in fact, a stone which was supposed to be the place where the sun settled,
29:34at the moment of the creation of the world. So it was a powerful symbol of the sun,
29:39which inspired the shape of the Egyptian pyramids.
29:42In this case, the Red Pyramid and the Bent Pyramid would have been built at the same time.
29:47The two intended to work together as some sort of powerful resurrection device.
29:51There is a sense in which the Red Pyramid and the Bent Pyramid are counterparts.
29:57I think they were meant to work as a couple. One to raise the resurrected king up into the sky,
30:02and the other to bring him down by means of the sun's rays. And the proof that these two were
30:08meant
30:08to work together is that they're both the same height. So they form a monument to the sun,
30:14which let the pharaoh come back down to earth, and so on, in an eternal circle.
30:30So they were built simultaneously or consecutively, the interior of the Red Pyramid is very similar
30:36to that of the Bent Pyramid. The Bent Pyramid and the North Pyramid have similarities in their
30:42internal structure. They both have beautiful corbelled chambers. The chambers inside the North Pyramid
30:48are a little bit more beautiful. They are probably the most magnificent chambers ever produced in a
30:53pyramid. The final expression, I suppose, of the corbelled roofing. Inside the Red Pyramid,
31:00there's a succession of three magnificent corbelled chambers in perfect harmony, as though a carefully
31:06thought out design plan was followed to the letter. There's no evidence of any problems, hesitation,
31:12or making it up as they went along. Quite different, then, from the interior of the Bent Pyramid,
31:20where the LiDAR scan revealed many flaws in the construction process.
31:27Back inside the Bent Pyramid, there's another mysterious architectural element,
31:32a sort of chimney, which we've decided to scan digitally in an attempt to discover its secret.
31:37This vertical shaft is a bit of a problem because we don't know where it goes.
31:41It is not clear because there are no texts or no obvious structural reasons why or what that was
31:50intended for. So people are puzzled by it today. It is the first time it's been possible to film
31:57and scan this shaft from the inside. At a height of 15 meters, two huge blocks of limestone come together
32:06to block the way. It's a dead end, an unexplained cul-de-sac. What could it be for? The LiDAR
32:13scan could shed
32:13some light, but it is a tricky operation for Alban Brice Pimpour. He's going to need a very long extension
32:20in an extremely tight space inhabited by bats.
32:26I'm about halfway up the chimney, about 15 meters to the top, and my extension has got me to about
32:34six meters.
32:38That's not too bad, I think. We'll see what imaging we get on the computer.
32:44I'm knowing the bats. There are a lot of them up there.
32:48Every second, the device takes over 400,000 measurements.
32:54You can hear the scanner getting noisier and faster as the processor is warming up.
32:59It's having to calculate lots of different points in a pretty narrow space, so it's struggling to find
33:04its bearings. I'll bring it down. That should be enough.
33:11Thanks to the scan, we get, for the first time, a complete view of the chimney, with a level of
33:17precision never before achieved in this spot. When you visit the place, you wonder what's up there
33:24above your head. It's not clear at all, but here the laser scan shows us every little detail of the
33:30chimney.
33:32The results of the LIDAR scan produce some precious clues. We can clearly see the compartments for the
33:38two closing blocks, the two obstruction systems, the two blocks waiting to be tipped over to seal
33:43off the passage, but which are still in their untipped positions. In pyramids, blocks like these were
33:50intended to be tipped over to seal off the access to funeral chambers. Their presence shows that this
33:56chimney should have led somewhere. But strangely, the blocks remain in their upright positions.
34:04These blocks have remained in their untipped positions, meaning they were never closed,
34:08which makes you think that the plan had been to build a funeral chamber at the top of the chimney,
34:12but that they gave up on the idea. There was clearly a major change of plan.
34:22To try to clear up this mystery, the Egyptologists have had the idea of comparing
34:26this layout to those of other pyramids. In the end, it seems like the answer might lie
34:32with Sneferu himself and his first pyramid. Back to Médum, 45 kilometers further south.
34:42At Médum, there's a chimney, which leads to a small funeral chamber,
34:47which is good reason to believe that we have the same thing at the bent pyramid,
34:51an anti-chamber, a chimney. But in the bent pyramid, the funeral chamber was never built.
34:58It would seem then that the chimney in the bent pyramid was supposed to lead to a funeral chamber.
35:05But Sneferu's builders gave up on that original plan,
35:09maybe because of the technical difficulties involved.
35:15It's really difficult to lift things up a vertical shaft, and it's not very wide.
35:20Let's not forget that this was the first great pyramid. They're experimenting and adapting.
35:26Conducting the funeral up a 15-meter-high chimney, getting the pharaoh's body up there with the
35:30sarcophagus and all the funeral furniture would have required some acrobatic maneuvering,
35:34so it probably ended up not a very popular option. As with any architectural project that lasts decades,
35:41there are necessarily times when plans get modified, when people change their minds.
35:53So the Egyptians gave up on this shaft and had a radical change of plan.
36:00They decided on a second and totally independent orientation.
36:05While the entrances to Egypt's pyramids were always on the northern side,
36:09this new descending slope was brought in from the west. Yet another mysterious choice.
36:16The western entrance of the bent pyramid is very mysterious. There are no other Old Kingdom pyramids
36:23with such an entrance. The best solution would seem to be that it was a substitute
36:29burial complex intended for the burial of the king.
36:32Maybe this has something to do with ideology. The west was also where the dead lived,
36:38so maybe that was also another pathway for the king to enjoy another afterlife
36:44by going through the west the same way that most people went to the west at death.
36:55This corridor, symbolically, could have been where Osiris would meet the newly resurrected King Sneferu,
37:01in the western side, which led to Osiris' world, because that's where the sun sets,
37:06in the direction in which the dead go.
37:13Osiris was the god supreme of the underworld.
37:16All the dead of ancient Egypt would have to pass by him.
37:24The entrance to this second corridor is almost 33 meters above the ground,
37:29as high as an 11-story building, making it the highest entrance of all of Egypt's pyramids.
37:36There's two possible reasons for this. One is that it could have helped deter thieves from breaking in,
37:42but the other reason is that it actually elevated the king closer to the heavens,
37:47where his spirit wanted to fly out.
37:49The opening was invisible. It was perfectly hidden by a covering block.
37:55At the end of this second sloping corridor, almost 70 meters in length,
38:00a horizontal corridor 20 meters long, led to the funeral chamber.
38:11So here we are in the Holy of Holies, the funeral chamber.
38:15The amazing thing, when you get into this chamber, it's the state that it's in.
38:20You feel like you're in a natural cave.
38:23The walls have suffered some serious deterioration.
38:29This was the chamber intended to be the final resting place of the pharaoh's body.
38:33But the deterioration of the vault is quite startling.
38:37The corbelling of the ceiling is barely recognizable.
38:40It feels like being in an underground cave.
38:43They saw those problems in the burial chamber. There's evidence of serious cracking
38:50in the walls of that chamber.
38:52What happened for it to end up in such a pitiful state?
38:56Did Sneferu's architects make a mistake here?
39:00Seeing the state of the chamber, along with the results of the LIDAR scan,
39:04Frank Monnier makes an initial observation.
39:07The damage isn't only of a structural nature, it was caused by a reworking done by the Egyptians
39:13on the corbelling and the walls.
39:18After the chamber had been completed, with its corbelled vault at a height of 14 meters,
39:23the Egyptians suddenly decided to raise the floor of the chamber by filling it with masonry.
39:28And they did so twice.
39:33It's a total mystery. We have absolutely no idea why they decided to do that. It's unique.
39:39We don't see a modification like this in any other pyramid.
39:43But the modification is no longer present.
39:47There was all this masonry, which came up to here,
39:50but it was removed by explorers and archaeologists in the 20th century because
39:55they hoped to find secret passages or a sarcophagus that hadn't been plundered.
40:01In the last century, the archaeologists working on the pyramid removed practically all the stones
40:07in the hope of finding a secret passage or, even better, Snefru's sarcophagus.
40:14But they were soon disappointed. There was no trace of the pharaoh and no secret passages,
40:20just a gaping hole. But their efforts did clear the space,
40:24thereby revealing the traces of the modifications done by the Egyptians.
40:29You can clearly see on the sides some slabs of the first load of masonry that was removed
40:33by the archaeologists. And you can clearly see, just above the cedar beams,
40:38that there still remain some elements of the floor of that first load.
40:42They're sticking out a bit. That was the first load of masonry that was removed.
40:47And the archaeologists' labors did result in one incredible discovery.
40:54They revealed this ancient timber work. All the beams you see there are over 4,600 years old.
41:00They're original. You can touch the wood. It's still firm. It hasn't suffered the ravages of time at all.
41:06It's absolutely wonderful. It's a step back in time.
41:10If you buried wood in Europe, it wouldn't generally last more than a few years.
41:16But in ancient Egypt, and in Egypt generally, the climate is so dry, it's so arid.
41:21There's a lack of humidity. And so that wood, which is, you know, 4,500 years old, has been preserved.
41:28It's thought that this timber work provided a temporary stay,
41:31a support for the walls while the chamber was being built.
41:38The wood is Lebanese cedar, which had to be brought here from the coast of the Middle East.
41:43You couldn't find any timber suitable for construction purposes in Egypt.
41:48Palm trees are very fibrous and wear out quickly, so they never used them.
41:52They had to go looking for wood outside Egypt.
41:55The Egyptians were trading with Lebanon, and the cedar would have to have been cut from the mountains,
42:00brought down to the sea, and then transported to Egypt. And it's extraordinary that this happened.
42:07In terms of construction, this kind of wood would be much more solid and strong.
42:15But these wooden structures were in no way responsible for the degradation of the state of the chamber.
42:23Having raised the floor, Sneferu's builders decided to rework the vault to obtain smooth walls,
42:29no doubt to achieve an effect more befitting a funeral chamber.
42:36But architecturally, it was a serious mistake.
42:39You can clearly see the straight side here. The korbelling has been worked away.
42:44And they did this up to a certain height. But what was the result of this reworking?
42:49An unequal distribution of the forces. It undid the whole principle behind the construction of the vault.
42:56The vault was no longer able to bear its load, and the ceiling started to deteriorate.
43:02The blocks were jutting out too far from the walls and ended up giving way, cracking and even falling.
43:07Look up there. That's pretty impressive. This is a straight-sided part of the wall.
43:12They must have left some blocks in too unstable a position, and they caved in.
43:17I'd say there's a good chance the stone started to crack and fall even while the pyramid was still being
43:21built.
43:22To check the state of the chamber in greater detail, Frank asked Albonbris to scan the entire room.
43:29But the task isn't that easy.
43:31The conditions inside a pyramid are always a bit special.
43:34It's not always easy to get around. The atmosphere is a bit warm, and it quickly gets oppressive.
43:39So you can't stay long. You have to be very efficient and get the data quickly.
43:46It is purely thanks to this miniature mobile scanner that the operation is possible at all.
43:52The data it gives us will be unique and unprecedented.
43:56After he's finished, Albonbris can immediately check on his phone that the scan has been successful.
44:03This is a quick preview to check that it worked. It looks fine to me, so now I'm impatient to
44:09see what we get on the computer,
44:10because there'll be a lot more detail and some color.
44:14It takes Albonbris a few days to create a 3D model of the chamber.
44:20The details are stunning.
44:24Discovering these new images of the chamber, especially with the negative view,
44:28Frank Monnier makes a somewhat worrying observation.
44:31You can see it very clearly. The scan has revealed some joints that are completely open.
44:36What you're seeing is empty space. And this empty space sometimes continues behind the blocks of
44:41the corbelling. So that means either an open joint or fissure with part of a block ready to fall.
44:47Here we see a piece of block which sooner or later is going to fall.
44:51The LiDAR scanner has shown that the structure may not be totally stable.
44:56Here we have plenty of elements whose stability is a bit precarious.
45:02It's safe to say that this fissuring will continue for centuries
45:06if we don't take measures to preserve and consolidate this chamber.
45:12This then is how this superb corbelled vault, intended to crown the funeral chamber,
45:18gradually crumbled away to end up looking so dilapidated today.
45:28No doubt because of the structural problems that kept getting worse inside the pyramid,
45:33the Egyptians finally decided to seal off the entire western passage, the second they had built.
45:42The structural problems caused them to close the western passage, plug it completely with limestone blocks.
45:51A ramp would have had to be built for this, up which they could haul the huge blocks of limestone
45:57that would be used to plug up the passage.
45:59You have to try to imagine the enormous difficulty of plugging up this sloping passage that's about 67 meters long.
46:05You must have dropped in blocks weighing several tons, which would have hurtled down at great speed
46:11one after the other, to completely seal off the corridor.
46:15But the builders had to find some way of making access to the funeral chamber still possible.
46:22They decided, therefore, to quite simply hollow out a tunnel through the edifice's masonry.
46:27It was done during the construction of the pyramid to allow workmen to easily go between the two complexes of
46:34chambers.
46:35Ironically, the northern entrance became the entrance for the higher western chamber, all because of these structural problems.
46:43Every small step, you can see they're responding to challenges, to structural problems.
46:50We asked Frank to take us through this tunnel.
46:57About 20 meters long and roughly hewn through the limestone blocks, this sinuous corridor is particularly narrow and uncomfortable.
47:12You can imagine the problems the Egyptians had to face digging this tunnel.
47:17Just squatting to get through it now is quite an ordeal.
47:20So just imagine the Egyptian workers who had to dig it and carry heavy objects through it.
47:26That's something.
47:30A LIDAR scan could reveal how these workers managed to hollow out this corridor blind,
47:35right through the heart of the limestone.
47:40It takes Albonbris an hour to scan the entirety of the corridor, but the result is spectacular.
47:47The details of the masonry, the measurements calculated to the millimetre, the volumes,
47:53everything appears in digital form.
47:55And before our very eyes, this 3D model reveals the amazing engineering technique perfected over four and a half thousand
48:02years ago.
48:03At first sight, you'd think they'd just dug through blind that the workers at this end started their tunnel,
48:10and those here started their tunnel, both hoping they'd meet.
48:13But it wasn't left to chance at all.
48:16To make sure that the two teams would meet, both teams made a bend, a sort of deviation.
48:21If they both went off this way, they were bound to meet sooner or later.
48:28The precise route of this linking tunnel proves that it could only have been created by the builders themselves,
48:34and not thieves long after the pyramid was finished.
48:37The fact that it goes directly between the two chambers does suggest people knew exactly where they were going.
48:43It does show a level of expertise. It shows that they were able to dig a tunnel through existing masonry,
48:50but also that they were able to direct the inclination and the direction of the tunnel.
48:55That could have only been possible if there were plans for them to consult.
49:00So it was via this narrow passage that Snefu's funeral cortege would have had to pass,
49:06to carry the pharaoh's mummy to his sepulchre, the funeral chamber.
49:16But one mystery remains regarding this tunnel dug for the transportation of the mummy of Khufu's father.
49:22And it's the big question that's still bothering Egyptologists.
49:26Did the dead pharaoh ever come this way?
49:29In which of his three pyramids was he finally laid to rest?
49:34So far, no sarcophagus has ever been found, neither in the pyramid at Medam,
49:39nor in the bent pyramid, nor in the red pyramid.
49:43But the clues suggest that the pharaoh would have chosen the perfect red pyramid as his gateway to the afterlife.
49:49I think it's compelling that Snefu was buried in the North Pyramid,
49:53in the true pyramid that he had long wanted to achieve.
49:58There he could be buried in the reflected light of the sun god itself.
50:02It was successful in creating the vision he wanted.
50:05It had all the things he wanted in the pyramid design itself.
50:09So, most probably, that's where he was buried.
50:12It was the last pyramid built during his reign,
50:15and it offered all the guarantees of security and stability that he could expect from his resting place for eternity.
50:23Yet, troublesome details still muddy the waters.
50:26What if Snefru's body is actually in the most mysterious pyramid of all, the bent pyramid?
50:33This is where the worshipping took place.
50:35It was to this pyramid that the priests came.
50:37It was where offerings were made for thousands of years.
50:41So, the Egyptians themselves definitely thought that this is where the king was buried,
50:45and then he would go to heaven.
50:49Whatever the case, the name of Snefru, while perhaps not known well to the general public,
50:54has gone down in history as that of the greatest builder of ancient Egypt.
50:59Snefru builds more pyramids in terms of cubic meterage than any pharaoh of Egypt.
51:06So, on those terms, he is the greatest builder in stone, at least in ancient Egypt,
51:12if not in the whole ancient world.
51:16The three pyramids together comprise about 8.3 million tons of stone,
51:21a weight equivalent to 820 Eiffel Towers.
51:25The figure is hard to imagine.
51:27The quantities of material and the amount of labor needed being off the scale.
51:32And all this, 2,600 years BCE.
51:37Despite the problems encountered in its construction,
51:40the bent pyramid has survived the centuries to stand before us today,
51:43like no other building in Egypt and perhaps in the world.
51:48And the lessons learnt by Snefru's architects of the bent pyramid,
51:52made the construction possible of those absolute masterpieces of antiquity,
51:56possibly the world's famous buildings,
51:58the pyramids of Giza.
52:04The world's famous features of the наст.
52:05The world's famous and famous number of craft were since the 19th century,