The Secrets of Saqqara Pyramid's Architecture | FULL DOCUMENTARY

A vast pyramid with an unusual form dominates the Nile Valley. It is the tomb of the pharaoh Djoser in the necropolis of Saqqara, south of Cairo. The pyramid of Djoser is amazing. It's the first, the most complex, it marks the start of the era of pyramids. An architectural revolution took place under the reign of this pharaoh with the construction of a high monument built entirely in stone. It was an explosion of building in stone. Surrounded by a vast wall, the pyramid is at the center of an immense burial complex with kilometers of secret tunnels running beneath it. They were not only putting 15 hectares on the surface, they were also creating a whole netherworld below the step pyramid complex. To achieve this, a whole population was mobilized. It wasn't slaves who built the pyramids. It was people who believed in that religion. For almost two centuries now, archaeologists have been trying to solve the mystery of the pyramids and find answers to their many questions. How did they build such tall structures without modern tools? Where did the millions of blocks used for their construction come from? How did the Egyptians manage to reach a height of 60 meters? And was the world's first pyramid built according to a clear plan or was it the result of chance? For the first time, archaeologists in the field have benefited from new technologies like laser scanners and photogrammetry to uncover fresh clues in this investigation that began 200 years ago. Photogrammetry proves very useful because now you can think about it, look at it, look at it again and again Most of the great discoveries happened when we look first from above, down. For the past five millennia, these monuments have stood the test of time. The giant pyramids have fascinated successive generations. But you have to look beyond the most celebrated examples to unveil the mystery of their origins. An hour from Cairo, far from the bustle of the tourists, on a deserted track on the Saqqara Plateau, sand stretches as far as the eye can see. Then, suddenly, a strange mountain looms on the horizon. It is the Pyramid of Djoser, which has dominated the Nile Valley for 4,600 years. This was the very first pyramid in history and it was the first monument built entirely of stone in ancient Egypt. It heralded the age of the giants, which spanned more than a thousand years and bears testimony to the pinnacle of Egyptian civilization, which dominated the world. This was the time of the pharaoh Djoser, the first king of Egypt's third dynasty. He is thought to have reigned from 2691 to 2625 BC. His kingdom was so mighty that the pharaoh embarked on an architectural project unprecedented in the history of humanity. The monuments that his predecessors made weren't higher than 10 or 12 meters, whereas this jumped to 60 meters. It was revolutionary. Its dimensions are spectacular. The rectangular base measures 121 meters by 109 meters and it peaks at 60 meters. In this desert plateau, everything was flat. Erecting a sort of artificial mountain must have been very impressive in the eyes of the Egyptians. This was the skyscraper of its age. Destined to receive the mortal remains of Djoser after his death, its unique shape made it immediately recognizable. We don't yet have the smooth-sided pyramid of Cheops, which appeared a century later, but a step pyramid, as Egyptologists call this design. The tombs of previous dynasties were made of earthen bricks, which are easy to produce and light to transport. But they had a major disadvantage. Brick easily crumbles. It's exposed to the wind, it wears down, and after a few hundred years it will disappear. In the eyes of the Egyptians, stone is eternal. It encapsulates the possibility of building an eternal resting place for the pharaoh. Stone may be internal, but it's also much heavier. It requires technical skills for cutting, transport, and installation. Nonetheless, the Egyptians embarked on this challenge on a huge scale. And suddenly they're building in stone on a scale of 15 hectares, the size of a large town in the 3rd millennium BC. An enclosure wall that's 1,645 meters long. It was an explosion of building in stone. On the plateau of Saqqara, Djoser built in stone not only his future tomb, but also a vast burial complex. And this mammoth project was completed in record time. What was all achieved within this reign of Djoser is amazing, because they think Djoser reigned 19 years. For a prototype, it was a work of genius. So exactly how did the Egyptians accomplish this technological and architectural revolution? There are no texts that recount the construction of the pyramids, so researchers like Bruno Deland have no choice. To reveal the secret of Djoser, they must make the stone talk. Fortunately for them, there has been spectacular progress in recent years in terms of scientific imagery. New technologies like photogrammetry, 3D scanners and geophysical prospection and georadar have all meant great progress in the knowledge of the construction of the pyramids. These technologies today allow us to measure the pyramid and its surroundings with great precision and visualize it from angles that would be impossible for an archaeologist on the ground, allowing us to discover unsuspected new locations. To reveal the mystery of the pyramids, photogrammetry is one of the most promising new technologies. In 2018, a major scientific expedition carried out the first full scan of Egypt's eight biggest pyramids. Photogrammetry is a technique to produce a 3D reconstruction of a site or monument. It generates a 3D model of what's visible, so you get a very accurate model of the pyramid thanks to precision of less than a centimeter. To achieve this level of detail, the team of specialists equipped with imaging equipment and a drone cover each square centimeter of the site, taking tens of thousands of photos. The drone has the huge advantage of height, offering an unprecedented vision of the pyramid. This allows you to see the pyramid and the surrounding terrain. We can then zoom into the pyramid to have a resolution to the nearest millimeter. We can obtain several levels of detail down to small cracks which appear in the same 3D model with the dunes all around. Thanks to this model generated by powerful computers, archaeologists can study it for the first time from new angles and go in a single click from the tiniest detail to an aerial view. Photogrammetry proves very useful because now you can think about it, look at it, look at it again and again from a God's-eye point of view. We're right here at our desktop. They hope to unearth fresh clues, like anomalies in the ground that might provide the key to the construction methods used for the pyramid. For 200 years, researchers have roamed this huge site, but its exceptional size makes it impossible to fully grasp from the ground level. What do you do, a balloon or you climb up? It's an examination of the pyramid that has not been possible until photogrammetry, until drones. We can see great things from above. Most of the great discoveries happened when we looked first from above down. Seeing the site from above is then essential. Photogrammetry allows us to see with precision the boundary of the complex now buried under the sand and to easily carry out precise measurements. The first thing we can see is that the pyramid of Saqqara is located in the exact center of the site. The pyramid was therefore not conceived in isolation. The whole site covers 15 hectares, the equivalent of 20 football pitches. But to understand the pyramid, one first has to understand the burial complex in its entirety. They were parts of big building complexes which had an essential function for the king's tomb, guaranteeing blissful, eternal life. The photogrammetric model allows us to measure the exact size of the town that stood around the pyramid of Djoser. To the south, an entrance with colonnades and a tomb. To the east, two palaces, one to the south, one to the north, and a series of small temples. To the north, butting against the pyramid, another funereal temple. And all these buildings lay within a protective wall. All the architecture components were within, beside the pyramid. The pyramid is nearly in the center of it, moved a little bit to the northwest corner, and it's surrounded by dummy buildings, buildings that aren't real, don't have interior rooms and so on. They're basically facades filled with debris. A whole town without inhabitants or life, a city dedicated to the afterlife. This whole complex is almost like a Disneyland, you know, a movie set. Creating this imulacrum of a royal complex, it has a magical effect. The site today may seem immense, but this is just a small part of what Djoser had built. There is another city, more secret and more holy, a city that was invisible to its contemporaries. For Mark Lenner, an archaeologist who has devoted his life to the study of the pyramids, the most extraordinary part of the vast Djoser site lies beneath the surface. It's an exceptional thing to be going down under the step pyramid of Djoser, because for many years, decades, nobody could go underneath. The archaeologists who have ventured under this pyramid since the start of the 19th century discovered an underground city made up of countless tunnels. Since 1992 and the major earthquake which damaged the pyramid, it has been strictly forbidden to come down here. In 2010, the Egyptians launched an ambitious restoration project to save the edifice with a view to reopening it to the public. In the meantime, we have had the exceptional privilege of being allowed to visit this subterranean world. It's a tunnel in the bedrock underneath the pyramid, but it's really in the form of a tunnel carved right into the natural rock. This maze of tunnels stretches almost 6 kilometers on three levels and goes down to an incredible depth of 40 meters, the equivalent of a 15-story building. Even for an experienced archaeologist, these tunnels are a labyrinth. There is a genuine risk of becoming lost. I have to say, frankly, it's so complicated down here, I'm kind of playing it by ear, as we say in English, because I don't know it by heart. But why did the Egyptians risk their lives to dig down so deep and so far? They thought that they began to make the corridors to save the thieves. I don't really believe in this. These corridors are the vision of the ancient Egyptians for the afterlife, that the king has to go through these tunnels and having knives in his hand, killing the wild creatures until he can actually go and meet Osiris. So we have to realize that when they built the step pyramid complex, they were not only putting 15 hectares of architecture for the first time in stone on the surface, but they had 5.7 kilometers of underground tunnels and passageways and chambers. They were also creating a whole netherworld below the step pyramid complex. But it was only in recent years with the restoration that Bruno Delonde has actually mapped everything in 3D using laser scanning. Starting in 2004, a scientific mission scanned the whole of the pyramid. Carried out in particularly difficult conditions, the work lasted three years. The aim was to produce a model of the pyramid and its tunnels in three dimensions. This would allow analysis of the pyramid structure which had been weakened by the earthquake in 1992. A 3D scanner projects a laser beam over the nearby walls and thereby establishes the volume of the space. There's a head on a tripod which turns in a few minutes and collects hundreds of millions of measurements with a precision to less than a millimeter. The initial result is a cloud of dots, a very dense network of hundreds of millions of points that gives us a model which we can work with on a computer screen. We can note information and identify structural weaknesses. The laser is stopped by the surfaces it encounters, but its extreme fineness and precision allow it to penetrate the smallest of gaps. It can thus detect fissures that would be invisible to the naked eye. When you have a wall and the dots go beyond that wall, you know the laser is passing through somewhere. Then you can look for where exactly is it getting through. The full scan of the underground structures revealed the existence of previously unknown tunnels that traditional archaeological techniques had not found. In total, five new tunnels, five ramps, appeared to us. This discovery revealed an extra kilometer of underground city, and the scan confirmed the intuitions of the first archaeologists who worked on this site. This network of tunnels is centered around the pharaoh's tomb. After 30 minutes of arduous progress, Mark Lehner finally reaches the funeral chamber where the remains of the pharaoh Djoser were laid. His tomb is an imposing mausoleum of granite, four meters high and more than three meters long and two meters wide. The tomb is surrounded by scaffolding for restoration purposes, temporarily hiding it from the archaeologist's view. Yeah, under here. One can only reach the tomb from above, and it's quite a struggle. Just a little light brushing, you still can see. By removing the sand that has accumulated over time, they find the stone steles which cover the tomb. Each is engraved with an inscription. There they are. I think that might be them. There were numbers indicating the order that the blocks were supposed to be put into place. This must be the first time that the royal body was put into a granite vault, so it wasn't at all common at this time. Granite is a resistant, hard stone. It is the ideal material to conserve the pharaoh's mummy and its magic powers for eternity. This granite vault is like a battery. When they put the king's body in, the battery was packed and the pyramid was energized and full of magical, spiritual power for those who came after. Yeah, in a way, this is the core of the pyramid. The pharaoh's tomb is positioned at the center of the edifice, but it is not at the actual heart of the pyramid but instead is located beneath it. The 3-D scan shows the precise dimensions of the funeral chamber. It's a square with 7-meter-long sides located at the bottom of a shaft some 22 meters deep. This is totally unique. In all of the pyramids that were subsequently built, the arrangement is radically different. There is no subterranean network and the king's tomb is inside the edifice. So how do we explain why Djoser's pyramid was an exception to this construction plan that would rule for the next 1,000 years? Jaromir Creci thinks he has found the answer by examining the pyramid. He was surprised to find that what we see today is not the original outside of the structure. Here we are, in fact, inside of a pyramid. It's an exceptional thing. And why did it actually happen? Because the pyramid cladding is several, some 4 meters, 5 meters away from us. The polished stones, which once covered the pyramid, have practically disappeared. Only a few at the base allowed the first archaeologists to measure the distance between the surface at the time and the surface today. In Djoser's day, the pyramid was 5 meters thicker. That means thousands of stones have disappeared. The cause was not erosion over time. It's thanks to, or because of, the fact that stone thieves removed the masonry that was between the core and the cladding. And they took away the cladding itself over the past thousands of years, and the stone was used for other buildings. Archaeologists believe that the pyramid at Saqqara was made of stone all the way to its center. This theory was confirmed in 2007 when a scan of the entire edifice was done. Some 320 million laser measurements enabled precise internal mapping of the monument. The verdict was unequivocal. The core is completely full. At that time, they didn't yet build funeral apartments within the pyramid itself. But it is still unknown why the pyramid was built like this. They didn't have the techniques. They were hedging their bets. It was the first time anyone had built so high. Holding up 60 meters of stonework over a funeral chamber was quite a gamble. There was a risk that the pyramid would collapse under its own weight and destroy the royal tomb. So the Egyptians chose to protect it by putting it underground. They embarked on this unprecedented project while keeping risks to a minimum. But how did Djoser manage to build his pyramid so high? At the time, traditional techniques only permitted the construction of mastabas, burial structures that only stand a few meters tall. The name mastaba simply means bench in Egyptian Arabic. The shape of the pyramid with its steps might lead one to the wrong conclusion regarding its construction. You would think, and it's been said, that Djoser or his genius architect had the idea to put one mastaba on top of another and voila, there you have the step pyramid. But it's not built like that. That method of construction would have been disastrous for a very simple reason. The difficulty is that they were lifting materials a bit like Lego bricks, and if you pile up Lego bricks one on top of another to a great height, there's a strong risk of collapse. The higher a building rises, the more it is subjected to horizontal forces and the greater the risk of collapse. Which means that piling up mastabas would not be a viable method to erect a monument 60 meters high. What made it possible to build a step pyramid to a height of 60 meters was the invention of the technique of arranging the construction elements in sloping courses. The technique of sloping courses consists of inclining blocks of stone towards the center of the monument at an angle of around 15 degrees. Arranged this way, the blocks press towards the middle of the structure, ensuring its overall stability. The advantage is obvious. All the elements lean towards the center, to the core of the monument, so there's no risk of movement and therefore collapse. It's actually built like a core that's like a tower, and then each step is made of accretions, like the skins of an onion leaning against it. Sloping courses, discovered by the first archaeologists to study the site, was the revolutionary technique which allowed the Egyptians to dare to think big. The photogrammetric survey, which produced the 3-D model from 15,000 photos of the site, has enabled a more precise calculation of the height of the monument. But the final result was not the expected 60 meters. The highest point was less than 58 meters. But if one adds the stones that have disappeared in successive pillaging, specialists agree that the pyramid did indeed measure 60 meters when first built. And in 2010, science unveiled another secret about the Pyramid of Saqqara, the exact date of its construction. Here we have a very important technical detail in front of us, the use of these cedar wood beams. It's important to say that, thanks to C14, we can get an accurate date of the pyramid's construction. Located at the monument's first level, inserted at the heart of the construction, C14 dating has revealed the precise date of this architectural revolution, 2570 B.C. The Egyptians accomplished an exploit, and with that, humanity entered a new era, as important as the advent of printing or electricity, or sending the first man into space. We may know how Djoser built his pyramid so high, but we have yet to understand why the pharaoh wanted such a monument. Was it really to access the afterlife and guarantee eternal life, or was it simply to assert his power over the people? The pyramid was propaganda, and, you know, like modern dictators, modern rulers will make large monuments in order to influence the people that they rule. Now, were they consciously doing that, or did they also really believe? All the texts found by archaeologists confirm that the pharaohs considered themselves as living gods. By ensuring eternal life for their kings, the pyramids offered protection from wars, epidemics, and famines. For Egyptian society at the time, they promised prosperity and peace. You have to understand that the pyramid was a national project of the whole nation. Therefore, the whole country helped the king. I do believe that the population in that time were only three millions, and those three millions, all of them participated in building the pyramid. It wasn't slaves who built the pyramids. It was people who believed in that religion, in the power of the sun god. On the contrary, it was an honor to work on those monuments. Djoser threw everything into this undertaking. In barely 19 years, he built not only the first stone pyramid, but also a whole town covering 15 hectares. This required a general mobilization of the populace, with farmers, boatmen, functionaries, and priests, all working to support some 10,000 front-line laborers working on the site. The construction of a cathedral, for example, might take more than 200 years. When you compare the volume of materials and the energy deployed, what the ancient Egyptians accomplished was quite outstanding. But religious fervor and general mobilization are not enough to explain how Djoser completed his grand design. What technical and logistical resources did the pharaoh have at his disposal to build such a town? Vassil Dobrev thinks that studying the burial complex reveals that the Egyptians already knew the secrets of stone. You can see that it's perfectly cut, even with tiny details. So you can tell these people weren't learning to cut stone at that moment in time. The Egyptians had been working stones for many centuries, but on a different scale, for stone dishes, floors, for slabs, for doorways, and so on. So they already had this scale, but it wasn't being employed on such a grand scale. The scale may have been grand, but the equipment was limited. The Egyptians didn't have any trucks or cranes or jackhammers. The tools at their disposal seem fairly rudimentary to us. Excavations carried out on the site since 1924 have found many tools, most common being the wooden mallet and copper chisels. Their dimensions vary depending on the rock to be cut and the motifs being carved. The problem was that copper is too soft to be used on harder stones. But Djoser's craftsmen found a way around this obstacle. To cut blocks of harder stone, like granite, they used dolerite, an even harder rock. Dolerite could be found in the form of small stones in the shape of a ball. They used it to strike the stone, which was broken and shaped like this. The Egyptians acquired extensive knowledge about stone and achieved miracles which still inspire incredulity today. The Egyptians, they know the anatomy of any stone. The stone is like us, like a human being. It has weak parts and strong parts. I can bring you a man, and I did that in front of a man who used to attack me all the time that the Egyptians cannot cut stones and move stones. I brought a man in the age of 70. He stood in the top of the stone. He made a line on the weak parts of the stone. In the middle, a piece of iron, boom, boom, boom. He cut it. They got the best out of what was available to them, and they achieved some extraordinary results. This site was a great opportunity to experiment and to hone some new techniques which would be used on other pyramids. At the Djoser Pyramid, for example, we can see that the size of the stones, the blocks, is smaller than in the later pyramids of the 4th dynasty. And there it seems that the engineers of the time, the builders, were still using something like mud bricks, so even the format of the blocks was similar to mud bricks. In just two decades, progress had been so rapid that it was visible to the naked eye. We can observe an evolution in the use of materials. The first stones used for construction were relatively small, whereas those used later were much bigger. It started with stones of 50 to 100 kilos, and later you have stones which weighed as much as 500 kilos, in other words, half a ton. Because the bigger the stone, the more efficient it is. The Egyptians understood the advantage of using bigger blocks. It's a way of rationalizing the work to save on materials. The bigger the blocks you use, the less cutting you have to do, and you have less waste from stone cutting. So the building of the Djoser Pyramid means a huge milestone in the development of Egyptian architecture and society, and we can really see a huge technological progress within several decades. And not just technological, but also the development of logistics, which was needed for that. Photogrammetry is a powerful tool for archaeologists. It finally allows them to accurately calculate the mass of stone necessary for the construction of the Pyramid of Djoser. They arrived at the figure of 271,900 cubic meters, a phenomenal volume to which must be added the volume of stones that have been stolen. Transporting them would have required the equivalent of 30,000 heavy trucks. But where did all this stone come from? That is one of the most challenging questions which has puzzled generations of archaeologists. The burial complex is located in the middle of the desert. There is just sand for kilometers all around. So where did the millions of blocks required for the construction of the complex come from? You know, one of the things is to identify where are the quarries associated with these pyramids. The first two decades that I was working in Egypt, I often wondered, well, what about the steppe pyramid? Where did they quarry all that stone? Surprisingly, the answer lay beneath the archaeologists' feet, on the Plateau of Saqqara itself. An aerial photo gave the specialists a first clue. Closer inspection indicated the presence of a significant anomaly in the terrain that is invisible from ground level. Excavations to the south of the complex, immediately below the perimeter wall, revealed the presence of a huge ditch dug in the rock of the Saqqara Plateau. Here we carried out an excavation to see how this mountain had been made, and the trench is even deeper. We went down about 20 meters. The burial complex is thought to have been surrounded by a huge ditch, like a moat of a castle. It's hard to imagine today because it's filled in with sand. You have to think, I'm floating in empty space here. Not only is the steppe pyramid complex the size of a large town for the third millennium, but it's on this pedestal, surrounded like a castle by this moat, you see. These discoveries fired the imagination of the researchers and posed numerous questions. Is that moat the quarry? What about the volume of stone missing from it? Does it equal the volume of stone in the steppe pyramid complex? Egyptologists are now pinning their hopes on archaeology 2.0. Thousands of photos have produced a digital model with amazing precision. Marc Lenner closely studies this 3D model of the whole site, from the aerial view down to the smallest detail. And his attention is drawn to the ditch. Moving about the point cloud of Saqqara, you can see the moat. This aerial photograph is a one-time still frame. Here we can look at it in different perspectives. It follows the line of the enclosure wall. There seems to be a depression, a linear depression all around, and it even looks sort of like a paper clip. This allows you to take that kind of landscape analysis. Photogrammetry helps to establish the dimensions of this giant ditch. 28 meters deep, 40 meters wide, and 2 kilometers long. You know, it's a feature of the steppe pyramid and the steppe pyramid complex that we're still trying to comprehend. I think we still don't fully understand the scale and the significance of this moat. The figures are dizzying. The excavation of this ditch beneath the perimeter wall could have provided 1 million cubic meters of stone. This would easily have been enough to build the pyramid, requiring 300,000 square meters along with the burial complex. This ditch probably provided most of the material for the construction of Djoser's steppe pyramid. Comparative analysis shows that some construction material did indeed come from the ditch. The ditch was primarily a quarry which provided an abundant source of materials for this pharaonic project. The quarry and pyramid were so close for practical reasons. It was simply easier to use blocks that were found on site to avoid having to move them over a long distance. Building the future pyramid alongside the source of the construction material was a stroke of genius. The Egyptians eliminated the main problem of the age, transport. What bright mind lay behind such inventiveness? The name of Djoser will forever be associated with the first pyramid in the history of humanity. But there is another name that features large in this story. A name that archaeologists found alongside that of the pharaoh in hieroglyphics. Imhotep, the architect of the pyramid. This is the only known occurrence in the history of ancient Egypt of a living god being associated with a mortal which underlines Imhotep's importance. Imhotep held an extremely high position in the hierarchy of the time. There was probably the pharaoh Djoser and below him the man in charge of affairs of state was no doubt Imhotep. So Imhotep was most likely responsible for all the constructions at that time. This man was a scholar as illustrated by his many other titles. Scribe, physician, high priest. And long after his death the Egyptians worshipped Imhotep as they would a divinity. Imhotep was considered by the ancient Egyptians to be the god of writing, the god of architecture, the god of stones. But where did this brilliant architect get the idea of a pyramid? Archaeologists have looked in vain for any clues that would tell the story of this architectural revolution. Zahi Hawass thinks that some information might lie within Imhotep's tomb. But so far this has never been found. Walter Emery, an English archaeologist, dedicated his life to the search of Imhotep. He spent years excavating. He died before he found the tomb of Imhotep. And therefore it is my dream to search for the tomb of Imhotep at Saqqara. It is the dream of all Egyptologists. Since Imhotep's tomb could well contain key elements that might help solve the final mysteries of the construction of the pyramid. Bruno Delaunde has a hunch as to where Imhotep may be buried. As the architect in charge of archaeological heritage for the United Nations, he led a scientific mission between 2004 and 2007, the aim of which was to x-ray the inside of the Pyramid of Djoser. During this survey, he came across a particular type of wall inscription, a seal which put him on the trail of Imhotep. One often finds in the tunnels inscriptions of a seal which show the work has been approved by the architect who came to oversee the project. Imhotep certified that the work had been done correctly. In the deepest part of the underground city, one tunnel and its contents, located just 1.5 meters below Djoser's tomb, attracted his attention. This tunnel is much more prestigious. There was a sarcophagus and the walls lined with blocks of stone which you don't find in any other tunnels. And between these blocks and the joints, there are imprints of cylindrical seals which associate Imhotep and Djoser. This is no longer about signing off on the work. This is a matter of decoration. This mural inscription suggests that the tomb found here was indeed that of the great architect who designed the first ever pyramid. My theory is that Imhotep, who was a close advisor to Djoser, could well have been laid to rest in this tunnel. Deland will not find the seal there today, because since his earlier mission, the tunnel has undergone some major changes. Consolidation work started in 2010 to save the pyramid from collapse required that the stone lining and the joints bearing the inscriptions be removed. On the vertical and horizontal joints, for long distances, you could see the names associated. And we are 1.5 meters from the burial chamber of Djoser. No other member of the royal family was as close to Djoser's tomb. Fortunately, the seals had been carefully documented using a digital imprint, technology once again proving a valuable aid to the researchers. Meanwhile, the identity of the tomb's owner remains unclear. The quest to solve the secrets of construction continues. Archaeologists are meanwhile trying to establish whether Imhotep had envisioned the construction of a pyramid right from the laying of the first stones. To answer this key question, they are once again going to rely on technology 2.0. Thanks to their amazing precision, photogrammetric images allow the various elements of the building to be identified. The Pyramid of Saqqara was not built in one go. Evidence of some very distinct ruptures are clearly visible on the 3D model. These signs have led archaeologists to think there may have been an initial square-shaped construction like a traditional tomb called a mastaba. He started to make a mastaba because he didn't know how to build a monument in stone. So it was a trial, and it worked. This initial success no doubt incited Imhotep to be more ambitious. By observing the pyramid on the ground, the different stages of construction can be seen. The second stage is to increase the four sides of the mastaba. Because the one in the middle until here is the first mastaba. And the increase happened here in the four sides. Then what happened on the east side only, the engineer thought to make another addition. The following stages consisted in enlarging the mastaba, which goes from a square to a rectangular shape. This base is the starting point of an ascension in four stages, and it would be further enlarged to receive two additional stages. They decided to build a small monument, and perhaps the trial proved conclusive. So this small pyramid, in the eyes of the architect or perhaps the pharaoh, was maybe still unsatisfactory, and they turned the audacity up a notch and decided to build a monument 60 meters high. For a prototype, it was a stroke of genius. We now have evidence which shows that Imhotep proceeded in stages, but was he following a pre-established plan? Study of the underground city surprisingly suggests that Imhotep changed his plan several times. The 3D scan reveals that many access shafts had been covered over during the construction, and a fresh one dug in the rock nearby. The labor must have been colossal, but they did those things. And it's just, you see again and again how they designed as they built and changed their mind. I really think that this increase came to his mind while he was building the idea of the steep pyramid. 5,000 years ago, the pharaoh Djoser and his brilliant architect Imhotep engineered an architectural revolution which changed the world forever. A colossal project that was accomplished in just 19 years. Archaeologists are beginning to understand how this exploit was achieved, but the Saqqara site is far from having revealed all its secrets. You might think it's frustrating to not have all the keys to comprehension, but on the contrary, that's what motivates us to continue our studies and to go further. New technologies are powerful tools, helping to solve the mysteries of the construction of these stone giants. The best way to understand the pyramids is not to focus only on the pyramid itself, but to turn your back to the pyramid and look at the surrounding landscape.