"Secrets of Lost Empires: Inca"

PBS Airdate: February 11, 1997
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NARRATOR (KEACH): We now return to Secrets of Lost Empires. In this hour, the Inca engineered an Empires. Now, a modern day team struggles to reconstruct their legacy. Inca.

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NARRATOR (KEACH): The Peruvian Andes of South America are among the most rugged mountain chains on earth. Battered by earthquakes, volcanoes, and powerful storms, the Andes are a dynamic land of environmental extremes. Steamy Amazon jungle quickly gives way to jagged, twenty-thousand-foot-high peaks. The spine of the Andes separates arid coastal desert from bleak, high altitude plateau. Too dry or too vertical for normal living, this land seems an unlikely place to find a great civilization. But five hundred years ago, an ambitious Andean people, called the Inca, were building spectacular cities in the clouds. Their intrepid engineers linked these mountain top citadels with a phenomenal system of roads. And gossamer-like suspension bridges made only of grass. Five hundred years ago, before the Spanish came to the New World, the Inca empire was the greatest in the Americas, stretching almost the entire length of the Andes.

ED FRANQUEMONT: The Incas were certainly the strangest and most bizarre civilization that the earth has ever seen. They had none of the things that we think of as the prerequisites for a major civilization, no arch, no wheel, no codified mathematics. They couldn't write. They couldn't even scratch down an arithmetic problem. And yet, they could do this amazing engineering.

NARRATOR (KEACH): The Incas' engineering medium was stone. In their walls and buildings, they showed a mastery over stone that is unrivaled. Without mortar, the Incas created walls of interlocking blocks that have successfully withstood earthquakes for centuries. But their interest in stone went beyond the utilitarian. The Incas worshipped rocks. They carved intricate designs on natural outcrops and poured chicha maize beer or sacrificial blood down the channels to honor their mummified ancestors housed in rock cut chambers below. Choosing high vantage points at sacred sites, the Incas created mysterious stone columns, dubbed "hitching posts of the sun." They worshipped the sun and may have used the shafts for sighting stars. Blending their stonework into the natural landscape , the Incas carved rocks to mimic the shape of the mountains behind. But their most impressive and mysterious stonework is found in the walls of their citadels. Giant blocks, some weighing a hundred tons, sit next to each other so precisely that not even a razor blade can fit between them. Without iron tools, draft animals, or the wheel, how did the Inca builders move and set such large blocks? To answer this question, NOVA invited several experts with widely different backgrounds to come to Peru.

JEAN-PIERRE PROTZEN: We're pretty good at finding the evidence today, if, and even if —

NARRATOR (KEACH): Professor of architecture Jean-Pierre Protzen studies the Incas' use of stone. He has written a book about Inca architecture and has some definite ideas about their construction methods. Ed Franquemont is both an anthropologist and a building contractor who lived in a Peruvian village for several years. His particular interest is how the Inca builders organized their labor force. Philippe Petit is the man who walked a tight rope between the towers of the World Trade Center. He wants to know how the Inca builders used grass to make the strong ropes that support their high suspension bridges. And he has come here to help build one. Vince Lee is an architect and explorer who has travelled extensively in the Andes looking for lost Inca sites. He has a theory about how the Inca stonemasons made such precise joints with such giant stones. A good place to start looking for clues is the citadel overlooking the town of Ollantaytambo. About five hundred years ago, a sun temple was under construction inside the fortress.

ED FRANQUEMONT: So with all these blocks of stones here, this is clearly a construction site that was abandoned in progress.

__: Yeah.

__: For sure.

ED FRANQUEMONT: The question is, where do these stones come from, and how did they get here?

JEAN-PIERRE PROTZEN: Well, they came from the quarries on the other side of the river at the base of this mountain here.

NARRATOR (KEACH): The team decides to follow the route to the quarry taken by the ancient stone haulers. The hike will take them down a sloping ramp to the valley floor. Along the way, they find massive blocks abandoned by the Inca workers.

VINCENT LEE: Yikes, JP, look at this thing. This is a big rock. There are more like this, on beyond here?

NARRATOR (KEACH): The villagers called these rocks "piedras cansadas"—weary stones. One legend tells of stones that grew tired, wept blood and refused to move.

JEAN-PIERRE PROTZEN: And so is there—so this is where the quarry is, the lower quarry at the bottom of this rockfall. You can see some ramps. The other quarry is way up there at the foot of the cliffs.

NARRATOR (KEACH): Jean-Pierre—JP to his friends—leads the team along the remains of a roadway that leads to the quarry—actually a rockfall created by rocks eroding from the cliffs above. Here, they find a 70-ton stone that Inca quarry workers had turned into a rectangular block. JP believes that all the boulders were first squared off in the quarry. But how did the Incas transport these heavy blocks down the mountain and up to the sun temple on the other side of the valley? Spanish chronicles tell us that the Incas did not possess the wheel or strong draft animals like oxen. David Canal, a community leader and Inca descendent, believes they hauled the blocks by hand. He has organized a team of pullers to transport a one-ton rock along the same route taken by the Incas between the quarry and the citadel. For most of its length, the ramp has a gentle slope. But halfway down the mountain, the incline suddenly turns into an almost vertical 800-foot chute to the valley below. With a block more than ten times the size of this one, it must have been extremely difficult for the Ancient stone haulers to negotiate this chute. Unlike the Inca blocks observed on the transport route, this boulder has not been squared off, and it tumbles out of control.

ED FRANQUEMONT: Probably not the way the Incas wanted to see it happen.

VINCENT LEE: No. No.

JEAN-PIERRE PROTZEN: Absolutely not.

VINCENT LEE: And you know, once it—if it turned this way, it was kind of cylindrical. It was kind of easy for it to get rolling, where a big square block might not have—

JEAN-PIERRE PROTZEN: That's true.

VINCENT LEE: —might not have done that.

NARRATOR (KEACH): Having gotten the boulder down in pieces by a distinctly non-Inca method, everyone hopes to do better with the next challenge: getting a block across the Urubamba River. At this time of year, the water level is at its lowest, and the river looks quite placid. But after the rainy season, it becomes a torrent impossible to ford. David believes the Inca hauling teams would have chosen to cross at the shallowest stretch. But even here, there is a stiff current, and many of his men can't swim. To appease the spirits of the river, David has arranged for an offering of cane alcohol. The wet stones are slippery for the men, but this turns out to be an advantage when it comes time to pull the rock.

ED FRANQUEMONT: We're ready? Let's go! Let's go. Yeah! Vamos! It was perfect! It was easier than moving it no the ground, went pretty quick. Just exactly like I thought it would.

NARRATOR (KEACH): The task of getting rock across the Urubamba turned out to be much easier than everyone had imagined. But crossing the fields on the valley bottom is much more of a problem, because the stone acts like a plow digging into the soft ground. There was probably once a road crossing the valley, but it has been destroyed by centuries of farming. Permission has been obtained to excavate one of the blocks abandoned in Inca times, to see if there is any evidence of a roadbed underneath.

VINCENT LEE: What turned up underneath was a layer of small stones on top of what appears to be a prepared gravel road base. So the resulting surface that the stone appears to have actually been bearing on is just these stones about the size of a softball—not necessarily round, but you know—and that's not unlike the surface we find on the ramps today, still.

NARRATOR (KEACH): Now that they have found the kind of road used by the Inca stone haulers, the team wants to see how difficult it would be to drag a much heavier block on a similar surface. In the plaza below the citadel, they find a genuine fifteen-ton Inca block, and the sloping cobbled surface is a good approximation of the eight-degree ramp that leads up to the sun temple.

DAVID CANAL: Listos... Uno, dos, tres ... (Ready...one, two, three...)

NARRATOR (KEACH): To pull the block, David has assembled a team of two hundred and fifty men, women and children from Ollantaytambo and neighboring villages. There is a festive atmosphere. Everyone has turned out to see the great block being dragged through town. Unfortunately, the stone refuses to budge. But after another offering of cane alcohol, and some levering, the stone finally comes unstuck. The ease with which the block travels on the cobbled surface proves that it could have been dragged up the slope to the sun temple.

DAVID CANAL: (English translation) I had no doubt that we could do it. Our ancestors did it, so I knew we could do it, too. Human labor can accomplish anything.

NARRATOR (KEACH): The determination displayed by David's people makes the speed and scale of the Incas' empire building achievements much more understandable. According to legend, around 1450 A.D., a leader called Pachacuti, whose name means "Earth-Shaker", began an aggressive military campaign that transformed the Incas from a small Cuzco valley community into a juggernaut that swallowed up all its Andean neighbors. In return for the benefits of a stable state, conquered peoples paid tax to their Inca masters in the form of labor. This huge workforce enabled Pachacuti and his successors to build the infrastructure that could support their rapidly expanding territorial gains. In the Urubamba valley, wide, rambling sections of the river were placed in canals to create cultivatable land. Terraces watered by elaborate irrigation schemes climbed the mountainsides, further increasing food production. On the peaks above the Urubamba River, the Inca lords built a chain of remarkable citadels in the sky. The most magnificent and mysterious of all: Machu Picchu.

ED FRANQUEMONT: It's difficult for us to grasp the scale of the Incas' imagination and ambition in producing places like this. As archaeologists, we like to work with potsherds or tools or walls or buildings—things that are people scale. But the Inca's vision was much bigger than that. The real Inca media was the entire, immense Andean landscape around him. He spent extra time to find very special places within the Andean landscape, spent time studying them to understand their true nature, embellished them with stone, ran sparkling and rushing water through prepared water courses, and in the end, produced works of singular beauty that represent a harmony with nature that few other civilizations have achieved.

NARRATOR (KEACH): So remote was its location, Machu Picchu's existence remained a secret from the time of the Incas until the early part of this century. But thirty miles up river, the town of Ollantaytambo has been lived in continuously since the time of the Inca. Its buildings are well-preserved. But the very finest Inca stonework is found in the citadel above the residential quarters. Replicating joints like this is the challenge JP Protzen and Vince Lee have set themselves.

VINCENT LEE: You know, JP, this part of Ollantaytambo has always been one of my favorites. I mean, this is Inca stonemasonry as good as it gets. Don't you agree?

JEAN-PIERRE PROTZEN: You're right. You bet.

VINCENT LEE: It's not just the craftsmanship. It's just the playfulness of the joining —

JEAN-PIERRE PROTZEN: Yeah. Right.

VINCENT LEE: —and the problem that they elected to solve is just so complicated. It's wonderful.

JEAN-PIERRE PROTZEN: Yes. Yeah. I mean, you really see that here, they perfected their skills.

VINCENT LEE: Yeah. And you know, the other thing it seems to me, that where other cultures used stone as a material for sculptural decor of one kind or another, these guys just use the stone itself.

JEAN-PIERRE PROTZEN: That's right.

VINCENT LEE: They're just telling you that stone is itself a beautiful material. You don't have to carve anything into it, really.

JEAN-PIERRE PROTZEN: No. No. This is sculpture, too.

VINCENT LEE: Yeah, exactly that.

JEAN-PIERRE PROTZEN: Yeah. Yeah.

VINCENT LEE: You know, people often say, oh, you can't get a knife blade in the joints of Inca—you can't get anything in this —

JEAN-PIERRE PROTZEN: Not even a razor blade.

VINCENT LEE: No! No, it's an absolute perfect joint.

JEAN-PIERRE PROTZEN: Yeah.

VINCENT LEE: I mean, the craftsmanship is mind-boggling, especially if you try to do it—

JEAN-PIERRE PROTZEN: Yeah! Yes!

VINCENT LEE: —if you try to duplicate it yourself!

NARRATOR (KEACH): JP has duplicated Inca stonework using Inca tools. In an ancient quarry, he discovered some rounded stones that probably came from the river. Using these as hammerstones, he found them as effective as the modern steel chisels used by stonemasons today. To create a bevelled edge, JP used a smaller hammerstone. The resulting tool marks are identical to those found on Inca masonry, rough in the center and smooth at the edges. But how did the Inca masons go about setting the stones? A half-finished citadel wall provides an important clue. To achieve the perfect Inca joint, an imprint is marked on the block below. The area that will seat the new block is then hammered out. Repeated fittings fine-tune the joint. Spots where stone dust is compressed indicate raised areas that need more hammering. Using ever-smaller hammerstones to avoid damaging the edges, JP finished the joint within a few hours.

JEAN-PIERRE PROTZEN: It shows that with the sort of simple tools that I found in this quarry, it is absolutely possible to achieve the kind of perfection of stonework that we observe throughout Cuzco and the Inca empire.

NARRATOR (KEACH): JP's method works well with small stones that can be easily maneuvered. But as the stones get bigger, handling them becomes increasingly difficult. Here at the Inca fortress of Sacsahuaman, the trial and error method of setting giant multi-ton blocks seems a daunting prospect. But despite their size, the blocks in the retaining wall all have the famous Inca fit, mortarless and snug. The answer may be a simple builder's tool called a scribe, a tool that may have enabled the Inca masons to make joints without any painstaking trial and error. Back in Ollantaytambo, Vince is about to use his scribe as he attempts to make a perfect Inca joint between two stones his masons have worked on for several days.

VINCENT LEE: We're getting the rock into position to scribe this prepared joint into this one that's yet to be prepared. And so far, everything we've done, anyone fitting these two rocks together would have to do. You would have to roughcut your rocks and basically decide which rock was going where. And you would have to get them in position. Now is the point where the method I'm proposing perhaps differs from others, because what I'm saying is that by using this scribe, this end, this blunt end is designed to work against a previously prepared smooth surface. Now what we have to do is make this edge exactly match it. And the way we do that is by taking this scribe and running it down this pre-finished surface, maintaining the string hanging through the center of its hole with this little plumb bob so that we don't accidentally mess up our joint by allowing the scribe to move in this plane. As long as we keep the string in the center of the hole, and as long as this is rubbing against that pre-finished surface, all we have to do is chop this rock out so that this end of the scribe exactly fits—no matter where we put the scribe. Then, we can achieve the fit we want by moving this rock one more time, simply closing the joint. End of story.

NARRATOR (KEACH): Time constraints have forced Vince's men to use steel chisels to work the hard andesite rock.

ED FRANQUEMONT: Well, this is it, the moment of truth for Vince's project. He's been scribing and chomping and chipping and polishing. And right now, these two stones are supposed to go together like Inca masonry, be right close together. What do you think? Gonna work? Gonna happen?

VINCENT LEE: Ed's absolutely right. It's time to stop talking and start moving rocks, so, so let's do it. The joint that we've gotten is certainly not as good as the ones we've seen up in the ruins. But it isn't bad. What we did here today is, we fitted two large rocks together, moving them together only one time. That's the essence of my idea, basically. So, we didn't have to try this back and forth at all. We fit it once and we got a pretty good joint. If you sent us down here for three more weeks, we'd do twice as good a job, I believe, because we'd know now, all of the mistakes that we made, and we'd know not to make them next time. But I think it's not too bad —

NARRATOR (KEACH): The second stage of Vince's experiment is much more complicated. He has to create a corner joint that fits perfectly with neighboring stones, both horizontally and vertically.

VINCENT LEE: In order to fit this corner right here of this stone into this seat that Hector is shaping, we have to bring this stone around and prop it up, above the seat that it's intended to fill, and then put poles under it, and you'll see perhaps these huaycos, or these notches in the rock, and that's what they're for. And we'll put poles under the stone. We'll probably leave some stones at this end, under the very tail end of the rock, and we'll be able to remove all these stones, so that it's hollow underneath the stone. And that gives us a place to use the scribe. And the scribe in this case is just like the other one, but it will be used in a forty-five degree orientation. It will come down the rising face and across the base. And you see, in order to get all the way across, we have to move all these stones out of the way, underneath the rock. That's undoubtedly the most tricky part of this technique.

ED FRANQUEMONT: I was one of the people who was healthfully skeptical of this whole system. But you know, it looks dangerous. It looks hard. And with a bigger stone, I think it would be more dangerous and more hard, and I still have my doubts. But there is an outline of a method. That stone is standing there, actually in the air above the space it's supposed to go in, propped up on those pieces of wood.

NARRATOR (KEACH): Vince believes that notches cut into the giant blocks at Sacsahuaman support his theory. But if it's a precarious operation, propping up a half-ton rock, what would it be like with a twenty-five-ton boulder?

VINCENT LEE: Looks very much like the surface we already have is very close to what we want. As we move it up, it comes out to three eighths. So just off hand, it looks like maybe we have to take a little more material off here. We're going to—we're now going to drop this stone into its seat and see how well we did.

NARRATOR (KEACH): With Vince rapidly losing his voice, his team is about to start the most hazardous part of the operation, lowering the block into place.

VINCENT LEE: By tipping the stone a little bit at a time, pull out a stick here, a stick there, until the whole thing creeps into place. This seems to be inherently less stable, and I think with a huge, with a huge stone would be even more unstable.

NARRATOR (KEACH): It is clear that Vince and company need to refine the procedure for getting the block off the stilts and into position, particularly if this method is to work with stones weighing many tons.

VINCENT LEE: This isn't bad.

ED FRANQUEMONT: Well, we've seen that this can be can be done, but the question is, is this how it was done? Did the Incas actually use this scribing method to construct their stone walls, to find their fine joints? I don't know. Do you think so? I mean, have we proven it?

VINCENT LEE: Well, as I said at the outset, I'm not sure we'll ever know how the Incas did it. The point of this was to try to find a way that works, and that would work with big stones. Now, in the case of the little joint we just fit here, we spent 12 days doing the rough work that any technique would involve, and one day doing the scribing. That tells me that the scribing is an efficient way to make the joint. Had we moved the rock five times and so forth, we might have spent 12 days doing the rough work and three days doing the, making the joint, a less efficient way to do it. But which way the Incas would have used, I don't know that we'll ever know.

NARRATOR (KEACH): The annual Ollantaytambo bullfight is in full swing. And yet another demonstration of how the Incas might have created their amazing stonework is being set up for a rather skeptical audience.

ED FRANQUEMONT: How curved it is affects the various focal lengths.

VINCENT LEE: Sure. Yes.

NARRATOR (KEACH): Professor Ivan Watkins teaches geoscience at St. Cloud University in Minnesota.

IVAN WATKINS: OK. And now, I need my goggles. I've looked at it too much.

NARRATOR (KEACH): Ivan and his wife, Berta, are here to test his theory that the Incas used gold parabolic mirrors to concentrate sunlight into a high temperature beam that could melt stone, or as Ivan would say, "thermally disaggregate" it.

IVAN WATKINS: You see that little image of the sun there? OK, now, the idea of this whole thing is to have an image of the sun from the big mirror projected across to a plane mirror and then use another parabolic mirror to direct the light to whatever is going to be thermally disaggregated. In this case, what we would thermally disaggregate would be a rock. OK, now, you can the bright spot that is there.

NARRATOR (KEACH): If Ivan's parabolic mirrors work, they will concentrate the sun's energy ten thousand times and melt this small piece of rock.

IVAN WATKINS: —whether I knock that little piece of rock off of it —

__: This is one of the stones —

NARRATOR (KEACH): Several years ago, Ivan was touring Inca sites, and this half-finished stone at Machu Picchu attracted his attention. Certain marks on the rock struck him as a clear indication of the use of parabolic mirrors.

ED FRANQUEMONT: You can see he thinks this line shows something to do with how it's cut.

NARRATOR (KEACH): Archaeologist Helaine Silverman is not convinced.

ED FRANQUEMONT: Think that's possible?

HELAINE SILVERMAN: I think it's ridiculous. There is absolutely no evidence that the Incas were using mirrors, and what's more, it's very clear what the technology of this is. They, they were, they were chipping away at this.

VINCENT LEE: I agree a hundred percent with you that this is a classic surface that's made by pecking the stone. Every one of these rocks has peck marks all over it.

NARRATOR (KEACH): But could stone hammers peck out the inside right angle joints that are so common in Inca walls? Ivan was convinced they couldn't. With no evidence of metal tools, Ivan reasoned the only alternative was a ray of amplified sunlight. Unfortunately, Ivan's prototype mirrors are not truly parabolic and fail to concentrate the sunlight effectively.

IVAN WATKINS: I'm not getting the temperature high enough there to pop him off.

ED FRANQUEMONT: The crux of Ivan's argument is that solar power concentrated through parabolic mirrors is the only way the Inca stonecutting that we've seen here at Ollantaytambo could have been done. But how about the stones that we've seen that have clear hammer marks on them? Are you saying that those were not —

IVAN WATKINS: Well, no, no. I'm not at all sure when you say they have clear hammer marks. What is the difference between taking —

JEAN-PIERRE PROTZEN: I think I want out of this. This is ridiculous. This is really ridiculous.

IVAN WATKINS: I need some goggles, though, because I just got blasted.

JEAN-PIERRE PROTZEN: I want to see this guy cut a stone like I can do. And then I talk. But otherwise that makes no damn sense.

IVAN WATKINS: If you can find a radius of curvature again —

JEAN-PIERRE PROTZEN: I mean, this is ridiculous.

IVAN WATKINS: —then it is necessary that indeed, that was not produced by hammering with a stone.

JEAN-PIERRE PROTZEN: All corners, inside corners in Inca masonry are rounded. There are no sharp inside corners.

NARRATOR (KEACH): JP appears to be right. There are no sharp, right-angle joints to be found. And even the tightest could have been created by polishing with a small hammerstone.

VINCENT LEE: Let's try burning this popsicle stick, and watch my finger. I've only got ten.

IVAN WATKINS: OK! OK, I'll try to, I'll try to not dedigitate you.

NARRATOR (KEACH): It doesn't seem to be Ivan's day. Just singeing a popsicle stick is a problem for his mirrors.

ED FRANQUEMONT: There we go. There's flame. There was some flame.

NARRATOR (KEACH): Down at the arena, things are not going much better for part-time matador Philippe Petit, where even the bulls refuse to get fired up. At its height, the Incas' rugged domain extended for almost the entire three and a half thousand mile length of the Andes. To control their diverse empire from the capital Cuzco, the Incas built a fourteen-thousand-mile network of all-weather roads. The vertigo-inducing terrain forced Inca engineers to build on steep mountainsides, sometimes carving trails right out of the living rock.

HELAINE SILVERMAN: Downhill, then uphill.

ED FRANQUEMONT: Well, this is really the nicest part of the trail.

HELAINE SILVERMAN: I know. These steps in the living rock are just fantastic.

NARRATOR (KEACH): Helaine Silverman has joined Ed Franquemont to explore one of the most dramatic sections of the trail. Not possessing the wheel, the Inca engineers designed the trails for foot traffic and cargo-bearing llamas. Inca relay runners stationed very few miles carried messages at a speed of one hundred and fifty miles a day.

HELAINE SILVERMAN: The system, the road system was so good that in ten days, a message could be transmitted from Quito in Ecuador to Cuzco, the Inca capital. That's about as fast as modern day postal service can send a letter between these two capital cities today.

NARRATOR (KEACH): A number of great rivers posed the most serious obstacle to the Inca road builders, particularly after the rainy season, when these waterways became raging torrents, impossible to ford on foot or cross by ferry. The ingenious solution to the problem? Suspension bridges that could span up to one hundred and fifty feet. One of these bridges crossed the gorge above the Apurimac river near the remote village of Huinchiri. The people here still build grass suspension bridges as their ancestors did five hundred years ago. It's said these bridges can be built in just three days. Ed and Helaine want to see how the community organizes itself into such an effective labor force. But one day before construction is due to start, the only sign of life near the bridge site is the harvesting of grass by Clotilde Vilcas and her family. It is sobering to realize that these dry-looking stalks will bear the weight of people crossing sixty feet above the Apurimac River. Clotilde's contribution to the community effort is to twist the grass into fifty yards of two-ply rope and deliver it tomorrow morning. As the first day of construction begins, the usually barren hills are suddenly crowded as local people start arriving at the bridge site. Villagers responsible for producing rope deliver their fifty-yard quota. In total, the bridge will require over seven thousand yards of half-inch-thick coya grass rope. Before construction begins, spiritual matters must be attended to. Chief bridge builder Victoriano Arisapana is making an offering to Pacha Mama, Mother Earth, to ensure her blessing on the enterprise. This ritual requires the consumption of large amounts of alcohol by the village leaders.

ED FRANQUEMONT: These people are every bit a part of the engineering as the bridge folks are—what they're doing is making the bridge strong and safe and last. And their job is to sit here and construct the payments that we make to the earth, and make sure that these cables go across and are completely strong.

NARRATOR (KEACH): High wire walker Philippe Petit cannot resist entertaining the crowd. With his life-long passion for knots, rigging, and cables, he is thrilled to be part of the effort. Attendance at the bridge site is carefully noted. By midday, almost five hundred people have turned up. The rope is divided up into sections, each containing twenty-four strands, one hundred and fifty feet long. The ropes are twisted together tightly and evenly. The flimsy-looking strands that were delivered in the morning are suddenly transformed into something substantial enough to entrust one's life to.

PHILIPPE PETIT: They are stranding the three main ropes into the final rope, into one of the final ropes. So they have to keep the regularity of the braiding, and they have also to be very careful about the torsion. Sometimes, they yell "nudo"—the knot, because something is twisted too much so it creates a, it creates—you see, when you take a rope like this, and you go like that, you see it creates knots, you see. So you have to take it out. Oh, it's beautiful, because each family did one little piece, each community brought their own rope. Those ropes which are like your little finger are braided into a bigger one, and then into those big ones, and now three of those big ones. It's really a communion.

NARRATOR (KEACH): By the end of the first day, these load-carrying cables are delivered to the bridge site. Each cable weighs about two hundred pounds. It's hard, heavy labor. But enthusiasm never wanes. Bridge building is as much a party as it is work, and probably always has been. The bridge builders are farmers living in homesteads scattered all over the high puna grassland. They are well adapted to working at altitudes of fourteen thousand feet and more, having long ago developed large capacity lungs and short, strong legs for climbing steep mountainsides. Like her ancestors in Inca times, Clotilde is very self-sufficient. She makes clothes for the family and barters for the food that she doesn't grow herself. Today, Ed has asked her to prepare a special Inca dish: guinea-pig.

HELAINE SILVERMAN: I think I have problems because we keep them as pets in the United States.

ED FRANQUEMONT: Well, it's not a dog.

HELAINE SILVERMAN: I know. No, and I know the whole history of the guinea pig. I know they're very important domesticated animals.

ED FRANQUEMONT: That's right. These are what you've been digging up.

HELAINE SILVERMAN: It's succulent.

ED FRANQUEMONT: Don't you like the wakatai?

NARRATOR (KEACH): Potatoes also came from the land of the Incas. But they have caught on better in the rest of the world than guinea pig. They eat well, because the hard work on the bridge is about to begin.

CLOTILDE VILCAS: Augusto!

NARRATOR (KEACH): The next morning starts with tossing a rope across the river. This will be used to pull the main cables over the gorge. NOVA has asked that the bridge cables be strong enough to carry at least five people and two llamas—the kind of load it might have supported in Inca times. On either side of the chasm, there are stone abutments that were constructed by the Incas. They were built into the side of the mountain in order to support the weight of the bridge. The cables are wound around stone beams anchored into the floor of the abutments, and they will eventually be securely tied off. But first, the cables must be tightened inch by inch, to get rid of any slack. Pulling the six cables taut takes the rest of day two. If all goes well, the bridge will be ready to cross in twenty-four hours. The morning of the third and final day finds the riggers swinging in the wind, sixty feet above the Apurimac River. It is not a vision that inspires confidence, but Helaine puts on a brave face.

HELAINE SILVERMAN: I feel a lot better about crossing this bridge now than I did before I saw it being built. And I think that it's structurally sound. I can even see that, as the people are building the bridge, they're already walking out over it before it's even finished.

NARRATOR (KEACH): Philippe, who has never felt more in his element, has been helping the riggers all morning.

PHILIPPE PETIT: OK, well, this bridge—I should say this piece of art—is now near completion. They are tying the footropes together, and they are doing the connection between the handrail and the foot. And it's done very fast. Son maestros—artistas!

NARRATOR (KEACH): With the bridge complete, a roll call is taken to confirm who gets paid. The Incas were great record keepers, too. It's been said that if even a pair of sandals were missing from their inventory, they would know. But how did they handle such information without writing or arithmetic?

ED FRANQUEMONT: Well, the Incas never had a written system, but it wasn't anywhere near as much of a disadvantage as you might think. Because they were able to store really abstract and complicated information using textiles as a medium. Right here, what I'm making is a small Inca textile, a quipu, a series of knots that keeps records on events that happened. In this case, I'm talking about how many people it took to build the bridge, how much it cost, the records we might keep. This is a "read only" document. After it's all done, what I'm going to be able to do is put on the finished records of what's going on here. It's not a counting device like an abacus, that counts as you go. Here, I've recorded how many people there were from the community of Huinchiri, who showed up to work for those six days. And here is how much we paid all their workers. And over here is how much we paid the authorities and the bridgemaster who did the bridge for us. We want to get back records years from now on how this bridge was made, how long it took, how many people it took, and what it cost. We'll be able to code them and keep them forever in a knotted string like this.

PHILIPPE PETIT: Now, the workers are taking a rest. And I am alone on that bridge, and I feel like a kid who is being given a giant gift. And I start enjoying myself as a wire-walker, as I can feel the balance a bit, you see, here. So, I don't know if I can even walk like this, but —

NARRATOR (KEACH): With an Inca bridge, all the load is carried by the four cables which make up the footpath. The hand ropes are only for balance. Helaine is warned that leaning on them too heavily could cause the bridge to flip over.

HELAINE SILVERMAN: I want to look down, but I'm afraid to look down, so I'm looking at everybody across. I know I can do this. I think I'm going to be sick. No, I'm not.

NARRATOR (KEACH): The llamas are even more reluctant to cross the bridge than Helaine.

ED FRANQUEMONT: Well, this bridge is certainly tremendous. It's an amazing example of how the Incas were able to accomplish tremendous amounts of work in a short period of time, billowing all over the Andes.

HELAINE SILVERMAN: In terms of labor organization, I feel as though I've been transported back five hundred years to the Inca times. I can just imagine the native leaders doing the census, saying, "OK, guys, ladies, you make the rope. Men, you lay out the strands. We are going to build the bridge. This is your labor tax."

ED FRANQUEMONT: The Incas were the largest empire of the pre-Industrial world, and certainly the richest. They had a control over this land, this wonderful and severe land of the Andes, that nobody could ever imagine. How they accomplished all of these things—we're just beginning to ask the right questions.

NARRATOR (KEACH): Tomorrow night, on NOVA's Secrets of Lost Empires. They were the pharaohs of Egypt, and in their honor stand massive monuments of stone. How were they raised?

__: You've got that Obelisk square. You want it, Roger?

__: Yeah.

__: These guys are either going to bust the Obelisk or they're going to get hurt.

__: You've cocked your gun.

__: Right.

__: You're ready to shoot.

__: Don't get in my line of sight!

NARRATOR (KEACH): Obelisk. Then, The Colosseum. It set the stage for mass murder. A typical day saw the executions of thousands of men and animals. But high above the blood and gore (inaudible) an enormous awning. How did the Romans erect such an immense roof? Colosseum. That's tomorrow night on NOVA. Now, log onto another lost empire. Ancient Egypt. At NOVA's website, navigate the tunnels, tombs, and temples of the pharaohs. And follow a real-time excavation at Quisa. Experience pyramids, the inside story. A NOVA PBS on-line adventure. To order NOVA Secrets of Lost Empires mini-series on videocassette, call 1(800) 949-8670. This five-hour set is $69.95 plus shipping and handling. Individual programs are also available for $19.95 each. NOVA is a production of WGBH Boston. NOVA is funded by Prudential.

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NARRATOR (KEACH): And by Merck.

__: Merck. Pharmaceutical research. Dedicated to the needs of an aging society. Merck. Committed to bringing out the best in medicine.

__: The corporation for public broadcasting, and viewers like you. Additional funding for this program is provided by the David H. Koch charitable foundation.

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NARRATOR (KEACH): To learn more about this subject, you can order the companion book to NOVA Secrets of Lost Empires by calling 1(800) 949-8670. Fully illustrated, this hard cover edition is $24.95 plus shipping and handling.

__: Coming on The American Experience, it was the worst winter ever recorded. They were hopelessly lost.

__: Even the wind seemed to hold its breath as the suggestion was made that were one to die, the rest might live. Then the suggestion was made that lots be cast, and whoever drew the longest slip should be the sacrifice.

__: A tragic tale of desperate survival, Madness and Cannibalism. The legendary journey of the Donner Party. On The American Experience.