"This Old Pyramid" (one hour version)

PBS Airdate: February 4, 1997
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______: Tonight, on NOVA: The great pyramids of Egypt, one of the wonders of the world. But just how were they built? In search of an answer, NOVA sent a stonemason and an archaeologist to Egypt. With an Egyptian crew and original methods, this odd couple will use mind and muscle to solve the mystery of This Old Pyramid.

______: NOVA is funded by Merck. Merck. Pharmaceutical research. Dedicated to preventing disease and improving health. Merck. Committed to bringing out the best in medicine. And by Prudential.

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______: The Corporation for Public Broadcasting. And viewers like you.

VOICE: You have come tonight to the most fabulous and celebrated place in the world. No traveler, emperor, merchant, or poet has trodden on these sands and not gasped in awe!

TOURIST: They're much bigger than I thought they would be!

ANOTHER TOURIST: It's absolutely breathtaking!

AND ANOTHER: That it stands for so long.

AND ANOTHER: Yes.

NARRATOR: Ever since they were built, four and a half thousand years ago, on the desert beside present-day Cairo, the pyramids of Giza have stirred the emotions. And the spectacle continues to amaze the thousands of tourists herded to the site each day.

TOURIST: All the 5,000 years of history is here. It's. . . I don't know, it just creeps over you.

NARRATOR: The most impressive pyramid and the largest was built by the pharaoh Khufu in 2600 BC. Known as the Great Pyramid, it was, until the early part of this century, the world's largest building, covering an area of seven city blocks and weighing six and a half million tons. The construction of Khufu's Pyramid was one of the most extraordinary feats ever of engineering, craftsmanship, and cooperative effort. In less than thirty years, the workers had to raise over two million blocks to a height of forty stories at the rate of one block every three minutes, an amazing achievement, given that the ancient Egyptians possessed only the simplest technology. Without modern surveying equipment, pulleys, or even the wheel, how did they lift stone blocks weighing two and a half tons, position them correctly, and control the shape of the rising pyramid? Despite a batch of new construction theories, the question of how the ancient Egyptians saw these engineering problems has not been convincingly answered. So, NOVA asked University of Chicago archaeologist Mark Lehner to come to Egypt and take a fresh look at the evidence.

MARK LEHNER: There's something about the pyramids here at Giza that inspires people to be very passionate about all kinds of different theories about what they hide, how they were built, what they mean. I have maps showing whole subway systems underneath the Giza plateau, hidden chambers and tunnels, great charts of circles and intersecting lines showing the mathematical relationships of these pyramids to each other, to the Sphinx, to the stars, to Bethlehem, to Manhattan. There are just files and files and files of these ideas. But the bottom line on all these ideas, including those of Egyptologists, is that they have to stand the test of bedrock reality.

NARRATOR: And what better test than to build one's own pyramid? To help him do this, Mark invited Roger Hopkins, a stonemason from Sudbury, Massachusetts.

ROGER HOPKINS: Aaaaw, God. Take it easy there, pal.

NARRATOR: The plan is for Roger and Mark to test out some of the more likely construction theories by actually building a small pyramid right here in the shadow of the Great Pyramid. Aiding Roger are fourteen skilled stonemasons from Cairo. They work for Mr. Ahmed who is in overall charge of the workforce. As none of the men speak English, and Roger's Arabic is non-existent, everything is a bit of a mystery at first. To understand how the ancient pyramid builders might have gone about their colossal tasks, Mr. Ahmed's men will confine themselves to the materials and tools available in ancient times as much as possible. The ancient builders constructed the pyramids with great care, as they were the sacred tombs of the pharaohs, designed to help ensure their immortality. To the ancient Egyptians, death was seen as just the beginning of a journey to another life, an afterlife that would last forever if things were properly organized before departure. First, the corpse had to be preserved by mummification, and then the body had to be protected from the elements and intruders by a burial chamber. Called mastabas, these tombs surrounding the pyramid were literally houses for the dead. They contained images of their owners, servants, and everything else needed for the afterlife. And there are whole subdivisions of them on the Giza plateau. The Egyptians believed that their kings became gods at death, who could then ensure an afterlife for everybody. So the pharaohs got the biggest tombs of all, stone mountains built to last an eternity. One of the most popular ideas about the pyramids, fostered by Hollywood, is that they were built by slaves. But Egyptologists have found no evidence to support this myth. Instead, the early pharaohs probably conscripted farm laborers during the annual flood of the Nile, workers who in ancient graffiti proudly described themselves as the "craftsman gang" or the "friends of Khufu." The very first pyramid was built here at Saqqara, just to the south of Giza, in 2700 BC. Up till then, mud brick was the principal construction material for tombs and other important buildings. But in the reign of the Pharaoh Zoser, his chief architect, a visionary called Imhotep, discovered a more versatile building material: stone. Stone gave them the confidence to put one tomb on top of another, creating the first pyramid in the form of a series of giant steps.

MARK LEHNER: So here at Saqqara, you can really see the beginning of this period of gigantism in pyramid building. It begins with the pyramid of Zoser, which is really the world's first skyscraper in stone, and the first pyramid in Egypt. It's a step pyramid, some think as a kind of symbolic ladder for the king's soul to ascend to heaven. This started, with a short interlude following Zoser, it began the period of really colossal, giant pyramids.

NARRATOR: The pharaoh Sneferu built the next three giant pyramids. A century of pyramid building had taught the ancient stonemasons many useful lessons. So when the pharaoh Khufu presented the builders with the epic task of constructing the great pyramid of Giza, they were ready. Unfortunately, Mark and Roger have rather less time to perfect their own building techniques.

MARK LEHNER: So basically, you have three weeks to move 189 stones into a pyramid?

ROGER HOPKINS: Right. Doesn't look like they'll fit all in this small square we're in, but. . .

MARK LEHNER: A pyramid of how big? How tall is it supposed to be?

ROGER HOPKINS: Well, it's a little less than six meters high, and probably about nine meters at the base.

MARK LEHNER: And you think this is do-able in three weeks? You're going to do this by ancient Egyptian methods? Are you going to be faithful to the way the ancient Egyptians do it, or are you going to come in here with a backhoe and a loader and a forklift?

ROGER HOPKINS: Well, let's put it this way. I'll be as—probably—as faithful as I can be, given that I only have three weeks here.

NARRATOR: Before moving in the first level of blocks, Roger and Mark want to double-check that the base of their pyramid is exactly square.

ROGER HOPKINS: I think maybe we're going to have to check to see if this is running square to our north line. If this line is off, then all our measurements are going to be off.

NARRATOR: A universal characteristic of ancient Egyptian pyramids was the precision with which the base was laid out and the four sides were oriented to face true north, south, east, and west. The sun or the stars were used to establish the north-south line. The next step was to lay out a square with precise right angles. The Egyptians could have done this in different ways. One method is to intersect two arcs. A line connecting the points of intersection will be at the right angle to the original line. Or, they could have used a triangle with sides of three, four, and five units, which always produces a right angle. Either way, the builders would have a virtually perfect square for the base of the pyramid.

ROGER HOPKINS: We're moving our first stone into the pyramid. This is going into the inner works of the support of our pyramid. It's what we call a core block. It's not finely dressed. It's very rough. We'll do that after it's in place.

NARRATOR: Although the men were able to roll the blocks end over end, it was a slow and laborious process. There's evidence that wooden rollers were used by the ancient Egyptians, so Roger tries some out on a nearby concrete driveway.

ROGER HOPKINS: This is a piece of cake, Mark. We could do it with about. . .

MARK LEHNER: This is ten men?

ROGER HOPKINS: Yeah. Ten men, easy. We're actually going up an incline right now that wouldn't be unlike coming out of the quarry.

NARRATOR: Rollers work well, but only on a smooth, hard surface. So, they're of no use on Roger's sandy site. At neighboring pyramid complexes, the remains of clay roadbeds have been found into which the ancient Egyptians imbedded wood, like railway ties. Perhaps a sled loaded with one of Roger's two-ton blocks will slide over this surface. Mark thinks it might.

MARK LEHNER: We're going to try to, within all the confusion, wet the ties and make it slippery, and see if it goes on the ties without a layer of slick clay. If the just the ties, the wooden ties themselves—sleepers. If the sleepers will carry the sled. Nobody thinks it'll work. They think we're crazy. They're irritated, massively irritated at even making the attempt. They think we're wasting our time. Roger doesn't.

ROGER HOPKINS: Ha-ha-ha!

MARK LEHNER: Hey, it works! Hey!

ROGER HOPKINS: The only drawback I see is that we're getting into a situation where. . .

MARK LEHNER: We want to do it all this way. Yeah! Get rid of the machines, Roger!

ROGER HOPKINS: Yeah, you do. You do, pal, but I don't. We've got too much of a deadline here to do it all that way. We're going to do plenty of it that way, when we get up in the upper levels.

MARK LEHNER: Well, I think it's good just to see that it works, because this is another case where hands-on, trial archaeology I think really proves some points. Because even the men, even the experienced masons here, were saying vehemently that this isn't going to work, and they were almost angry and irritated about it. And lo and behold, it got off the rollers.

ROGER HOPKINS: Yeah, but we're still not up on a ramp.

MARK LEHNER: It was a bar of soap!

NARRATOR: Although the sledding experiment is a success, Roger is opposed to building a network of clay roads, because it would delay work on the pyramid itself. Roger has also decided not to lay down a hard foundation underneath the pyramid. Instead, he'll build directly on the desert floor, a decision he'll come to regret. Protected by the surrounding desert, the Egyptian nation grew up along the fertile Nile valley. Together, the Nile and the pyramids played a central role in creating this unique civilization that was to last 3,000 years.

MARK LEHNER: The Nile was extremely important for pyramid building, because it was the main artery by which all non-local materials were transported to the pyramid site. The granite, for example. Fifty- to seventy-ton blocks of granite came from as far away as Aswan, 500 miles to the south. This could only have been brought by boat. The fine limestone for the outer casing was brought from the quarries at Tura, which is directly across the river, and this, again, could only have been brought by boat. So, the water of the Nile was the principal means of transport for moving these materials to the pyramid site for building.

NARRATOR: Today, Roger invites Mark and his friend Nick Fairplay, a stonecarver from England, to go with him to the Tura limestone formation where the blocks for his pyramid are quarried.

MARK LEHNER: But this is pretty much the traditional way, the way they've been doing it, probably, for the last, what? Four or five thousand years.

ROGER HOPKINS: This is about as deep as you can go, one man, from picking away at the surface in that narrow. It's just wide enough for them to get their leg down in there, and they really can't go much deeper than that. If they were going to get a bigger block, they'd have to widen the channel here.

MARK LEHNER: So the way they separate the block is by channelling these deep channels on three sides. But then, how do they pull it up?

NICK FAIRPLAY: Then they're splitting it on two sides with wedges.

MARK LEHNER: So, they just stick wedges underneath and, like, pry it up?

NICK FAIRPLAY: Yeah. They cut holes, basically, and then put the wedges in and hammer them in.

MARK LEHNER: And then that produces a horizontal crack that separates it from the bed underneath.

NICK FAIRPLAY: Yeah. Right.

NARRATOR: In ancient times, this fine limestone was used only for the outer blocks of the pyramid. Back on the Giza side of the Nile, Mark takes Nick Fairplay to the place where he believes the bulk of the pyramid stone was quarried. Early archaeologists didn't recognize this area as a quarry because the ancient workers had filled it with building debris. When later investigators cleaned it out, they concentrated on the tombs of the pharaoh's high officials which honeycomb the rockface. So until recently, archaeologists didn't fully appreciate this quarry's role in the building of the Great Pyramid.

MARK LEHNER: In this, they are just extracting a block, or they're just defining the block, and that represents about a standard pyramid-sized block. You know, it's amazing that with evidence like this, people have still wondered if the stone wasn't brought from somewhere else, like across the river. And it's clear to me, it's clear as a bell, that almost, you know, the bulk of the pyramid was quarried right here on the plateau and simply transported up the plateau for piling it up in the form of the pyramids.

NARRATOR: Mark's survey of the Giza plateau has produced the first accurate computer reconstructions of how the pyramids appeared four and a half thousand years ago. The Giza complex consisted of the pyramids of the pharaohs Khufu, his son Khafre, and grandson Menkaure. Each pyramid has a long covered causeway running down to the Nile, with a temple at either end. But there were also satellite pyramids for the pharaohs' queens, and hundreds of smaller tombs for the overseers and officials. The Khafre pyramid shows all the standard elements of a pyramid complex. Sitting right at the base of the pyramid itself is the mortuary temple, where the daily rituals took place. From its entrance, a causeway, once with walls and a roof, runs a quarter of a mile down the plateau, to end at the Valley Temple. The unique thing that Khafre added was the Great Sphinx, carved right out of the natural rock, with the body of a lion and the head of a pharaoh. The face is probably that of Khafre himself, making the Sphinx a kind of guardian for the whole pyramid plateau. Five days into his twenty-one day building schedule, Roger is only now moving in the first of the angled blocks that will form the sloping outer surface of the pyramid.

ROGER HOPKINS: This is our most important stone of the whole project. This is our first cornerstone and it's our casing stone, so it's the linchpin of the whole pyramid.

NARRATOR: When chiseled to the required slope, the casing blocks will give Roger's pyramid a smooth appearance. But on the ancient pyramids, most of the casing has long since been looted, exposing the rough blocks underneath.

MARK LEHNER: Up here at the top of the Khafre pyramid, some of the original limestone casing, the smooth outer shell of the pyramid, yet remains. Looking out across it, you get a sense of how sensational the pyramids must have been when they were brand new, encased with this polished white stone. Now, the casing has this brown patina, and it's been slightly roughed by the ages. But when it was new, it was as white as newly-fallen snow, and the effect must have been truly blinding.

NARRATOR: Because the casing stones need to be placed very precisely, Roger wants to lower these blocks into position with his front-end loader, but Mark is insisting on ancient methods. As the cornerstone is dragged in, it dislodges the baseline string.

ROGER HOPKINS: I didn't want to set it this way, remember that. It was much easier just to come in and set it down where it's supposed to be. I've got to reestablish that line all the way from my north-south line again in order to find this line.

MARK LEHNER: Right now, we don't know where the corner is. It could be anywhere in this whole area, right around in here, because this thing is bent all. . .

NARRATOR: Up on the plateau, the ancient pyramid builders didn't have this problem. They engraved permanent reference lines in the stone foundation.

DAVE GOODMAN: That's good!

NARRATOR: And working on a hard surface also enabled the giant blocks to be positioned with amazing precision.

MARK LEHNER: Roger, how much do you estimate this casing block to be, on the Khufu pyramid?

ROGER HOPKINS: It looks to me like about fifteen to seventeen tons.

MARK LEHNER: He says it's more than seventeen tons, but I want to know how they got this joint between two fifteen-ton stones so—how they did it so well. I can't put the blade of my Swiss Army knife—And this is often said. It would be hard to get a razor blade in that seam.

NARRATOR: As Roger tries to emulate the ancients' precise joints, he is once again stymied by the soft surface on which he is building.

ROGER HOPKINS: What's that Mark?

MARK LEHNER: Is that as good as you're going to get it?

ROGER HOPKINS: Well, that's pretty close.

MARK LEHNER: They're doing this by jamming stones in under this side.

ROGER HOPKINS: The problem we've got here, Mark, is that we're not doing our bottom casement stones on. . .

MARK LEHNER: You're not on a stone surface.

ROGER HOPKINS: We're not on stone surface.

MARK LEHNER: So they're jamming these pieces in.

ROGER HOPKINS: Right. So, we can't really get a very tight joint like what they did up on the big pyramids. You know, with a little practice, we could get those fine joints, too.

MARK LEHNER: But, you've got it now as fine as you're going to get it. You're not going to get. . .

ROGER HOPKINS: Well, you know. I mean, we've got other fish to fry here. Come on. That's it. Towards me.

NARRATOR: When Khufu's Pyramid was at this early stage in construction, work had already begun on the passageway leading to his tomb deep in the bedrock below.

MARK LEHNER: We are right underneath the very center of the pyramid, about a hundred feet under the original surface of the plateau, with the whole pyramid rising above us. We've come down here by a narrow passage about three feet in height. It descends for more than 345 feet, until we get down into what's called the Subterranean Chamber. Well, the Subterranean Chamber here, underneath the pyramid, gives us one of the clearest looks of how they proceeded carving out these chambers. Just like in their gallery, cliffside quarries, they proceeded in great channels like this. Not that great. About the size for one man to sit. And it seems from the stone that was left, which presents us, in effect, with a frozen moment in the construction/quarrying process, it seems that individual men were allotted cubes of stone which they had to work away, probably with a pick much like this, although of copper. And we can see very clearly how they were picking away the stone in these channels. In fact, some of the very chips of the last workmen to work in this little cubicle remain. And then they would lob off the hump of stone left in the middle of these channels. This is easy enough for us to imagine now when we see all these traces, but can you imagine what it must have been like when the men were working here? There must have been dust and debris everywhere. It must have been absolutely choking. And can you imagine what it must have been like for the workman who created this lead channel, a kind of shelf, to widen the room? He must have had to work practically, if not on all fours, then on his belly, swinging the pick away ahead of him to move the work farther into the solid rock. And again, the chips of these workmen yet remain as they did when somebody came, probably on orders for the king, and told them, "Put down your tools. We have a different plan. We want to make a chamber higher in the pyramid."

NARRATOR: So after months of exhausting labor, the Subterranean Tomb was abandoned, for reasons we may never understand. Then, the pharaoh Khufu ordered the construction of a second chamber, but ultimately, chose yet another burial chamber high in the pyramid. As Roger's pyramid begins to grow, he faces one of the most fundamental problems of pyramid engineering: How to lift the blocks. The traditional and widely-accepted method has been a straight-on ramp made of mud brick that grew with the rising pyramid. But pulling blocks up a ramp this steep would be virtually impossible. If the ramp had a more gradual slope, a gradient of one in ten, for example, it would be over a mile long, run past the quarry, and would be a bigger construction project than the pyramid itself.

MARK LEHNER: Well, some pyramid theorists say that there were no ramps whatsoever, that all the blocks were levered up from the very base of the pyramid all the way to the top, on the steps. What they're thinking of are very regular steps, like a household stairway. But when you come up here to the top of the pyramids, it seems inconceivable that these multi-ton blocks could have been levered up on steps, such as they exist.

MARTIN ISLER: When we lever this thing up, it's got to clear these things. Otherwise, you're going to get hung up here.

NARRATOR: Martin Isler is one of the major advocates of levering. His work as a sculptor, which involved moving large pieces of marble, convinced him that levering is the most efficient method for raising up the heavy blocks.

MARTIN ISLER: I love stone! All kinds of stone—pyramids, statues, anything. Anything build of stone, it just—one of my passions.

NARRATOR: Also a professional draftsman, Martin, on paper, makes levering look like a very plausible idea. But today, for the first time, he is putting his theory to the test. He has to lever a one-ton block up one step of the pyramid.

MARTIN ISLER: No loader! No loader!

MARK LEHNER: He says it's too heavy; we should bring the loader. But I told him we had to try it this way.

MARTIN ISLER: We have to try.

MARK LEHNER: The little guy will direct the operation. Adel is his name. He's a specialist in the use of the crowbar.

MARTIN ISLER: Wonderful. Adel. You see, this is good. That was no good. It has to be flat, OK? Like that. Flat. Yes? No, no. If it tumbles over, you're going to get hurt.

MARK LEHNER: No need to get excited.

MARTIN ISLER: Am I excited?

MARK LEHNER: Yeah!

MARTIN ISLER: I don't mean to. OK. Down, down!

MARK LEHNER: The cribbage is getting a little precarious. How's it look, Martin?

MARTIN ISLER: It looks all right. It's going up.

MARK LEHNER: They all say don't worry. It's not going to fall.

MARTIN ISLER: They're not worried.

MARK LEHNER: OK. They're not worried.

MARTIN ISLER: Well, I'm worried.

MARK LEHNER: Well, let's stay worried and cautious and proceed.

MARTIN ISLER: Yeah. OK.

ROGER HOPKINS: You know, I've been waiting for that block to get up there for the last couple of hours, and I don't think it's going to be a very practical way of bringing blocks up except in cases where we're absolutely walled off and that's the only method we can get them in.

MARTIN ISLER: But you could have a piece of wood that is four feet long, and you can have a piece of wood that is three feet long. And you can have a source of wood so that you could select wood according to the plan.

MARK LEHNER: So, you have standardized lengths?

MARTIN ISLER: Well, you could cut, like carpenters do all the time. They have stacks of wood. I use this piece, or I use that piece according to my needs.

MARK LEHNER: But this is an awful lot of wood, isn't it? It's a tremendous quantity of wood, isn't it?

MARTIN ISLER: But it's all recyclable. All of it is recyclable.

MARK LEHNER: What kind of wood do you think it was?

MARTIN ISLER: I have no idea. I have no idea. What kind of wood do you think it might have been?

MARK LEHNER: It's a country where wood is very scarce.

MARTIN ISLER: I understand, but they also imported wood from Lebanon. You've heard that.

MARK LEHNER: At great cost.

MARTIN ISLER: At great cost. But the pyramid was an important monument, wasn't it?

MARK LEHNER: All right.

MARTIN ISLER: Is it possible that having done this one trial, we have learned something, and the next trial would be performed even more quickly? Is that possible? And the third one, even better yet. And the fourth one, and the father will teach the son and the son will teach his son, and it gets better as it goes along.

MARK LEHNER: Martin, however they did it, I'm sure that's true.

MARTIN ISLER: Yeah. They did it! Look at the monument!

MARK LEHNER: Yeah. However they did it, that's true.

NARRATOR: After two intense hours, success. Ahmed's levering team has inched the block to the top of the next step. All that remains is a tricky maneuver to get the block off the precarious piles of wood.

MARTIN ISLER: You see the purpose of the block? You see where it landed? OK? Thank you. Thank you, guys. Thank you, all.

NARRATOR: With only two weeks before his completion deadline, Roger is not enthusiastic about using Martin's levering idea for raising any more blocks. Instead, he's pushing ahead with building a ramp to slide blocks to the second layer of the pyramid. The ramp is made of locally-available materials. Tufla, the desert clay, is combined with gypsum, forming an all-purpose mortar that binds everything together. Once the ramp is filled with stone debris, the roadway on top is formed by embedding timbers in a layer of clay. Today will be the first time Roger has attempted to pull a block up an incline on this surface.

ROGER HOPKINS: Once we were on the wood, we got that lubricant and the friction, we took right off. Are you still a lever man?

MARTIN ISLER: When necessary. Ramps when necessary. Levers when necessary. I mean, there's no such thing as one way only.

ROGER HOPKINS: I think sledding is a lot faster. Once you've got the rhythm, the teams trained, and the proper roadbed, I think you can move right along.

MARTIN ISLER: On the lower part of the pyramid, which is basically 87% of the volume of the pyramid, why not use ramps? But above that, you can use levers. Take advantage of anything you can make.

NARRATOR: Roger's ramp is similar in construction to one that Mark has noticed leaning against a tomb. It was probably built about the same time as the great pyramid that stands behind it.

MARK LEHNER: They must have been using it for the construction in some way. And all these books are written about pyramid building, and they say they made mud brick ramps. Other people say they didn't use any ramps. They say there are no ancient ramps. And we're standing on a ramp that's probably from the time of the building of this mastaba, whether they used it for debris or for these stones, and it's about 5,000 years old.

ROGER HOPKINS: Well, you can see the debris down here where it's very similar to the way that we're laying our stone and tufla in.

MARK LEHNER: And this isn't the only ramp that still exists out here at Giza. I mean, there are others for hauling stones from the quarries up to the cemeteries. There are construction embankments. This has got to be how they constructed the pyramid ramps. It has to be this material.

NARRATOR: With the ramp appearing to resolve the question of how to raise blocks, the other major challenge facing the ancient builders was controlling the shape of the pyramid. That's the next problem facing Roger and Mark.

MARK LEHNER: A pyramid is essentially a square and a center point. The trick in constructing a pyramid accurately is to raise that center point above the square without developing twist in the four faces. In order to do this, you essentially have to achieve a series of squares, one above the other, as the pyramid is rising.

NARRATOR: Each new square has to be properly lined up with the one below in order to form a true pyramid. If the squares are not correctly aligned, the resulting pyramid will be less than perfect. So, to avoid twist in his pyramid, Roger built a series of squares in the form of steps, called a step pyramid. In addition to keeping the pyramid square, the inner step pyramid may also help control the slope of the outer face of the pyramid.

NICK FAIRPLAY: What's important was the relationships of parts.

NARRATOR: Mark and Nick Fairplay believe that there is a close relationship between the step pyramid and the outer slope, and they assumed that Roger had built the step pyramid with this in mind. But on later investigation, it quickly becomes clear that Roger's step pyramid has not been built to Mark's specifications, and so does not have the necessary dimensions to control the slope of the outer pyramid.

MARK LEHNER: Ninety-one out here. 91.5. So, if this is 91.5, this measurement out was fifty something, and that's 50.5 centimeters, what's the relationship of these steps to this slope? Other than just keeping it square.

ROGER HOPKINS: Well, I'm only using it to keep it square.

MARK LEHNER: You're only using the step pyramid to keep it square.

ROGER HOPKINS: Right.

MARK LEHNER: We're not using the step pyramid to actually control the rise and run of the outer casing slope.

ROGER HOPKINS: No, no, no.

MARK LEHNER: As did the ancient Egyptians, according to some evidence at Meidum, for example, and in the Queens' Pyramids.

ROGER HOPKINS: You can't prove that for a fact for one minute, pal. It's only on record like three pyramids that they used a 51 degree angle, and the rest of them show a 53 degree angle, which shows you a vertical rise that's a 3-4-5 triangle.

MARK LEHNER: Well, this may be actually a really good point. You don't think there is any one rule by which they controlled the slope of the outer casing. You think they might have done it one way for one or two or three pyramids, and another way for a different pyramid? I think that's a pretty good statement and a good possibility, because I don't think there was a manual for pyramid building.

ROGER HOPKINS: No. You know, all they had to word with, from generation to generation, are just standard masonry practices which are the same today as they were 6,000 years ago.

NARRATOR: The mathematics used by the ancient masons was probably very simple. Through trial and error, the builders of the Great Pyramid learned that the proportions of eleven and fourteen would give them about a fifty-two degree angle, if these were incorporated into every casing stone before being put in place. By using these proportions, and by periodically sighting at the corners to check if the slope is true, Roger expects to end up with a perfectly-shaped pyramid, despite his disagreement with Mark.

MARK LEHNER: So, you're using basically common sense, practical experience, and a hands-on approach.

ROGER HOPKINS: Right. Exactly.

MARK LEHNER: You know, Roger, I'm just beginning to realize, maybe we should get off your case a little bit.

ROGER HOPKINS: Yeah. Get out of my acre!

MARK LEHNER: . . .with all this theorizing about the ancient stuff.

ROGER HOPKINS: It'd be nice to get on with just building this pyramid.

MARK LEHNER: Yeah.

NARRATOR: With only a week to finish the project, Roger has extended the ramp so it wraps around the back of the pyramid.

MARK LEHNER: Now, we're going to try to pull a sled, and we're going to try to turn a corner with the sled for the first time. We're starting out with a fairly small block, pulling it up the incline of the ramp, and around the first corner that the ramp makes around the pyramid. We might need more men to actually make the pull around the corner.

ROGER HOPKINS: We'll add them on as we need them.

NARRATOR: Critics of the ramp method question whether a heavily-laden sled can make a ninety degree turn. But Roger has a plan.

MARK LEHNER: Are you optimistic we're going to get in 'round the corner?

ROGER HOPKINS: We'll get it around the corner, hell or high water. Watch out for the rope! OK. Hold it, hold it. OK. Now we rearrange the ropes.

WORKERS: Hey la houp!

MARK LEHNER: Here comes the turn.

ROGER HOPKINS: We're all set. Well, it worked like I figured it would. I mean, I knew I was going to have a little problem on the corner there, but if that had been a five-ton block, we could have done it this same way. This is twice the grade we had before, easily.

MARK LEHNER: And I like the way you distributed the men going back down the ramp, and the pull as well, so that you're using the ramp in both directions.

ROGER HOPKINS: Well, there's no place else for them to go.

MARK LEHNER: It was a little bit complicated changing the ropes and so on.

ROGER HOPKINS: This is the first time we did it.

MARK LEHNER: It's the first time you did it.

NARRATOR: Roger only had enough time to build the ramp around three sides of his pyramid, but he was confident that he could have continued wrapping it around to the top. The success with the ramp convinced him that a similar ramp was used by the builders of the great pyramid. Mark and Roger's project has focused on figuring out how to build the main structure of the pyramid. But the ancient builders had to deal with engineering problems in the complex inner chambers as well. Deep in the heart of Khufu's Pyramid is his tomb. It was supposed to protect the pharaoh's mummified body for an eternity. But all that now remains is his empty granite sarcophagus.

MARK LEHNER: At first glance, this is a deceptively simple room. It's a box, lined with granite on the floor and the walls, and rooved with great beams of granite. But in fact, this is the first time that the ancient Egyptians attempted to span a distance this wide in their stone architecture. And you can see in the cracks in these great granite beams that weight up to fifty to seventy tons, that they developed problems. There were too many stresses on the ceiling beams. And had these broken and fallen down into the chamber, the engineers and stone masons would have been in deep, deep trouble.

NARRATOR: In an effort to build a tomb that would last forever, the pharaoh's builders reinforced the defective beams by adding four more granite ceilings, topped off by a pitched roof of limestone to relieve further stress on the chambers below. In the uppermost chamber, workers' graffiti include the name Khufu, the pharaoh whose mummified body required such elaborate protection.

MARK LEHNER: When the burial rights of the king were finished and the priests had left, the workmen whose job it was to seal off the pyramid, presumably for eternity, first had to slide great granite portcullis slabs like these, down these notches to seal off the actual entrance into the King's Chamber.

NARRATOR: The next line of defense against robbers was to plug the Ascending Passage with a row of granite blocks that were slid in place from the Grand Gallery.

MARK LEHNER: The only problem with this is once the Ascending Passage was plugged tightly, what were the workmen left with as an escape route? Right here, at the bottom of the Grand Gallery, there's a crude tunnel forced through the already-laid masonry of the pyramid all the way down to the Descending Passage, from whence they could go back up, out the original entrance.

NARRATOR: Despite the complex anti-theft devices, neither Khufu's Pyramid nor the hundred or so others that were built could resist the tomb robbers. The mummified pharaohs would not be left in peace. All the pyramids were broken into, and the bodies violated. Roger has his own problems. His assignment was to build just two sides of an eighteen-foot pyramid in twenty-one days. But with only three days to go, it looks unlikely that he'll achieve this goal. Rather than build the ramp any higher, Roger reluctantly tries to lever the last blocks into place. The attempt ultimately succeeds, but barely.

ROGER HOPKINS: OK. All right. We've got to get this sucker back up on. . . I told you to use the little rollers! You know, I've been trying to emphasize that these fulcrums have got to be just at the right height, and they've got to be steady and everything else.

MARK LEHNER: Well, this levering operation started out very methodically and worked very well, and you know, Roger organized it extremely well. And in spite of that, the closer he gets to the top, the more problems he's having. Running out of room for levers, running out of room for men to pull on ropes, and running out of room for the tall fulcrums that are necessary. And this bears out what everybody really had imagined, that the closer you get to the apex of the pyramid, the more problems there are in engineering the stones.

NARRATOR: By now, everyone was an expert on moving blocks, and there was much debate on the best method for putting the final pyramid stone in place. Once Ahmed's men got the block in motion, it quickly became clear that there could be no turning back.

ROGER HOPKINS: How about a little quiet! Let's get some rope on that so they can pull it. Maher's going to get crushed! It was kind of terrifying, I've got to admit. It was—I don't think if we had enough able-bodied people there, we probably could have lost it very easily. But, I think that final "hey-la-houp" pulled us through. I had no doubts that we would get it up there. I just prayed that no one got hurt.

NARRATOR: With fewer than two hundred blocks, compared to Khufu's more than two million, Roger's pyramid would have no difficulty sitting on the missing top of the Great Pyramid. And although the Great Pyramid is twenty-seven times taller, the achievement of Roger and his crew has strengthened Mark's understanding of the ancient techniques that permitted Khufu's builders to raise his great monument in less than thirty years. But that does not mean that all the mysteries have been solved.

MARK LEHNER: Well, I don't think there are any huge mysteries about the nuts and bolts of how they made a pyramid. I think more the mystery is the motivation behind the people. What caused them to do this all of a sudden? For the first time in history, they gathered, not hundreds or even thousands, but probably tens of thousands of people in one place at one time to do this project. What motivated them to do that? That's the real mystery.

ROGER HOPKINS: I've learned a lot of respect for the ancient Egyptians. I think they were pioneering in an area which no one else had been in, and I've got to give them a lot of credit for what they've done.

MARK LEHNER: Do you think they could build the real thing in twenty years?

ROGER HOPKINS: I think they could have, you know? What I've seen here is just absolutely amazing. I found that my masons, my quarry men, and my stone setters were all fairly accomplished, very good craftsmen. Shouldn't have come as a surprise; they had such a long history of thousands of years doing this. When I look at the Great Pyramid, the marvel there for me is not the stonework as much as the level of organization that these ancient Egyptians had, getting their society to pull together in such a way that they not only had blocks of stone, but bread on the table.

MARK LEHNER: Well, the real gigantic pyramids were built within the space of about three, maybe four generations. This was a unique moment in Egyptian history, and these pharaohs were seizing that moment to create pyramids that would stand forever.

NARRATOR: Time-honored monuments. Wonders of the ancient world. These giant structures reveal the beliefs, the lifestyle, the spirit of cultures long past. What they don't reveal is the mystery of how they came to be. Now, NOVA and a cast of hundreds use brute strength and sheer determination to rediscover the technical know-how of the ancient builders.

______: You got that obelisk where you want it, Roger?

ROGER HOPKINS: Yeah.

NARRATOR: An Egyptian obelisk. England's Stonehenge. Inca masonry in Peru. A roof for Rome's Colosseum. NOVA embarks on a four-part building spree to unlock the secrets of lost empires. Next time, on NOVA. Now you can tour the pyramids of Giza your way, using the latest on-line technology at NOVA's website. Navigate the tunnels, tombs, and temples of the pharaohs. And, follow a real-time excavation. Log on for Pyramids: The Inside Story, a NOVA PBS on-line adventure. To order this show for $19.95 plus shipping and handling, call 1-800-949-8670. And to learn more about how science can solve the mysteries of our world, ask about out many other NOVA videos.

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