古城马丘比丘 The ancient city of Machu Picchu

High in the Peruvian Andes lies the ancient city of Machu Picchu, a lost city of doorways and passages that hint at the ghosts of its past. Who were the mysterious people who built it, and why here? The answers lie below the surface, and mummy kings wait to share their stories. But will these revelations finally lay the ghosts of Machu Picchu to rest? Perched at 2,450 meters on a narrow ridge in the high Andes, Machu Picchu is a remote and mysterious ancient wonder. Spread across the top of this ridge are more than 200 structures, each built with exquisitely cut stone. Some appear to be homes, others temples. They surround a half-hectare green, and all are fed by open waterways and fountains, a place that is at once beautiful and baffling. There are no written clues in the city, no carvings to suggest a purpose. At its highest point, the mystery only deepens. There, a beautifully carved pillar stands, a graceful riddle to cap the sight. From this lofty height, the views leave one stunned, but also curious. How did the builders get all this stone up here, and then cut it so finely that they didn't even need mortar to hold their walls in place? Who built Machu Picchu, and why did they build it in this impossible place? Even more perplexing, why did they abandon it? Throughout the city, stone seemed to be on the verge of being placed when work came to a stop. Now, as never before, clues are emerging. The Inca rose to power in the mid-1400s, in part because they built such good roads. Much of their 16,000-kilometer network is still visible today. They left other evidence that they were master engineers and builders. Their terraces, canals, and stone cities rival those of ancient Rome. But unlike the ancient Romans, they did all of this without the wheel, without iron, and without a written language. But the most surprising detail about the Inca is that they ruled for only 100 years. Then their empire was decimated, first by disease, then civil war. Finally, the Spanish conquistadors. From the Spanish, we know that the last Inca emperor retreated into the mountains, to a city called Vilcabamba. The Inca held out at Vilcabamba for 35 years, until finally, in 1572, the Spanish destroyed the city. Strangely, they left no written record of where it was located, and the legend of the lost city of Vilcabamba was born. It was a mystery that had powerful allure. Almost 350 years later, it pulled an American explorer named Hiram Bingham here on a quest to find it. On the morning of July 24th, 1911, Bingham, camera at the ready, reached the top of a ridge, and stepped into history. It fairly took my breath away, he later wrote. Bingham's photos marked one of the first times that a moment of discovery had been captured on film. Today, those pictures are part of a rare 23-volume explorer's album detailing Bingham's discovery. But what exactly had he found? He called it by its local name, Machu Picchu, but he thought it was the lost city of Vilcabamba. A year later, when his team discovered over 100 burials, Bingham believed he'd found the evidence to make his case. After thorough examination, Bingham and his bone expert, Dr. George Eaton, reached an astonishing conclusion. 80% of the dead were women. Eaton's data gave a sex ratio of four to one, four times as many females as males. Four to one really would be a tremendous bias, and I think that's what got Eaton excited. He thought, my God, they're almost all women. What could explain a predominantly female cemetery? Bingham thought he'd found the remains of the so-called Virgins of the Sun. According to Spanish accounts, the most beautiful girls in the empire were chosen for this sacred convent. Selected around the age of eight, these virgins served the Inca emperor for the rest of their lives. Bingham guessed that when the last Inca king retreated into the mountains to escape the Spanish, he took his sacred virgins with him. So it all added up. The skeletons of the virgins confirmed that this spectacular city in the sky had to be Vilcabamba. Clearly for him, it created a great magical, romantic kind of picture that made good book reading. When published in the April 1913 issue of National Geographic, the story was an overnight sensation. Bingham became a star. The only problem was that the theory was wrong. Investigations of other Inca ruins revealed that the Spanish desecrated almost every Inca holy site they could find. At Machu Picchu, the entire city remained untouched. But the most convincing evidence against Bingham's theory was in the very bones he had found at the site. When forensic anthropologist John Verano reexamined them, he found that the sex of the skeletons was almost evenly split, a far cry from Eaton's four to one ratio. To figure out the sex of a skeleton, you have to compare it across many ethnic and racial groups. Eaton's references were limited to people of European or African descent. People in the Andes are relatively short, delicately built. Can only guess that what he was looking at was bone size. And he said, this looks like a small person, therefore it's female. In Bingham's collection, Verano also found the bones of several children and children and virgins just didn't add up. I just, I can't find evidence to support that idea that these were virgins of the sun. I think that can be pretty well ruled out. Without the virgins or any sign of Spanish desecration, there was no proof to support Bingham's theory that this was Vilcabamba. So what was it? With so few written records, archeologists like Fernando Estete must piece together clues about Machu Picchu's history, wherever they can find them. And he thinks he's just found one in a nearby town called Patayacta. Patayacta was important because it supplied the food for all the people living in Machu Picchu. Patayacta is a few hours walk from Machu Picchu along the main Inca trail through the region. It is the closest place to Machu Picchu where large-scale farming could have taken place. The people who lived at Patayacta weren't just farmers, though. They likely played many roles. They could have been stone workers, builders, laborers. Estete's best hope for understanding Machu Picchu is to learn about the people who lived here, the possible builders of the city. Above the old Inca town, up a nearly vertical slope, a local guide has found what looks like a burial niche. Estete and fellow archeologist, Elva Torres, believe it may be undisturbed, a gravesite last touched 500 years ago. Hola, que tal, Richard, que tal, que tal? Y la tumba? Before the tomb can be opened, Estete's Quechua guide makes an offering of coca leaves to the spirits that dwell here, just as his Inca forebearers would have done. Yeah. Estete and Torres have investigated many other burials in the area. Most are far more accessible. This tomb has been constructed. The other tombs don't use this style. They're simply in caves, in natural rock formations that are easy to get to. ¿Qué hay? ¿Se ve algo? No, profe, está oscuro. A ver, mira bien, mira bien, ¿hay algo? In the dim tomb light. ¿Ah, sí? No se ve bien, está oscuro. A human skull. ¿Qué hay? ¿Hay un cráneo? Sí, profe, hay un cráneo adentro. Hay cráneo, hay huesos bastante. ¿Qué hay? ¿Qué hay? Mucho hueco. Ya, hasta los costados, con cuidado. Ya, chico. Ya estás pisando, ¿no? As Torres enters the cramped tomb, the find only gets more tantalizing. It appears there's a couple of individuals. But as she investigates, she finds a lot more skeletons, nine in all, and many show signs of injury. Well, this problem regarding fractures, they could be from everyday activities. They could have been from a fall, something may have fallen on them, or perhaps some other sort of activity. In this case, they may have been working in the quarries. Could these be the skeletons of the builders of Machu Picchu? They can't be sure until they take a closer look in the lab. There, Torres is joined by bio-archaeologist Valerie Andruszko. Right away, they find some surprises in the skulls from the tombs near Parayacta. They're full of holes. It's the sign of a procedure called trepanation. Trepanation is the partial removal of part of the skull that the Inca practiced with very high degrees of success. Our understanding is that trepanation was often done in order to release intracranial pressure due to fractures. It's skull surgery, and healed wounds found throughout the empire show that the Inca were skilled at using it to treat head trauma. When we see evidence for trauma, the question is always, is it related to accidents, or is it related to violence? This individual right here, this is a complete fracture of the frontal bone. It has perforated all the way to the frontal sinus. This type of injury is not the type of injury that one would get from an accidental fall. To me, this is the type of injury more indicative of a weapon-type injury, possibly indicative of warfare. In fact, several skulls from the tombs show signs of blunt force trauma, the type of fracture you get from a club. So these weren't builders. They were likely warriors. Possibly these individuals may have been engaged in defense of the sites around them, possibly engaged in defense of Machu Picchu. This revelation stands in stark contrast to the appearance of Machu Picchu as a religious sanctuary. This is a city dominated by sacred temples and shrines, the Temple of the Three Windows, the Temple of the Condor, named for its carved floor and stone wings, the elegantly curved Temple of the Sun, built on a rock that is illuminated on the solstice, and at the highest point in the city, a stone pillar known as the Intiwatana. The evidence seems to be in conflict. Was Machu Picchu a military fortress or was it a religious center? In the ancient capital of Cusco, descendants of the Inca still live. Every year during the Roman Catholic Festival of Corpus Christi, statues of the Virgin Mary, along with 15 other saints, are removed from the cathedral and brought to the square. These performers may be paying homage to Christian saints, but the instruments they play and the steps they move to are actually Inca in origin. That's because this Corpus Christi procession is a Christian revision of an Inca ritual. 500 years ago, the Inca also processed through Cusco, but they didn't carry statues of saints. They carried the mummies of their kings, whom they revered as gods. It was likely one of these kings who built Machu Picchu. The quality of the stonework alone suggests the city was royal. Fernando Estete estimates that it would have taken at least 50 years to complete. Since the Inca Empire only lasted a hundred years, focus has been on the earliest kings. The accounts of a Spanish Jesuit named Bernabe Cobo point to a dynamic leader who founded the Inca Empire, a king named Pachacuti. But no one could ever prove that Pachacuti built Machu Picchu. A small clue is hidden in his name, which means he who remakes the world. Pachacuti was sort of the Alexander the Great of the Incas. He was the one who started the expansion out of the Cusco region, and the Inca Empire began to expand tremendously over areas that had never been conquered by the Incas before. What we know of Pachacuti's history is due in part to Father Cobo. Cobo arrived in Peru after the conquest in the late 1500s and wrote his account based on interviews with descendants of the Inca. According to Father Cobo, Pachacuti was renowned as a builder. Having enlarged his empire with so many in such vast provinces, during the remainder of his life, this king devoted himself to building magnificent temples and palaces and strong castles. The beautiful stonework at Machu Picchu, so similar in style to Pachacuti's temples in other Inca cities, suggests that the same hand was behind the structures here. But the most convincing evidence linking Pachacuti to Machu Picchu comes from a Spanish register held in the colonial archives in Cusco. Dated 1568, it mentions the town of Picchu with a clear reference to its owner, Inca Yupanqui, also known as Pachacuti. The evidence is convincing. It is Pachacuti, the first Inca emperor who ordered Machu Picchu's construction, and in a place that would give any engineer pause. If I was called in by Pachacuti and ordered to build Machu Picchu at that particular location, I would have gulped. Engineering-wise, it would seem almost impossible to handle. 15 years of study by hydrologist Ken Wright and a team of engineers is revealing how the Inca pulled this off. Because the steepness of the site isn't the only problem. Machu Picchu also receives torrential rains each year, triggering frequent landslides. And the site is crossed by not one, but two earthquake fault lines, making it a terrible place on which to build a city of stone. The location does have two virtues, a nearby freshwater spring, and a supply of granite. There's a quarry right on the site. When the Inca engineers turned to building, their first step would have been to shore up the mountain. They did it by constructing a remarkable bulwark of terraces. As Estede's team rappels further down the cliff face, they're discovering hundreds of new terraces hidden below. Usually when people refer to Machu Picchu, they are only thinking about the Inca buildings on top of the ridge. But construction has to begin at the bottom. In other words, you have to start with the terraces. Terraces are fundamental to Machu Picchu. While some terraces would have been used for small scale farming, their primary purpose was to hold the mountain in place while draining a huge volume of rainwater away. That averages about 76 inches per year. And in terms of, let's say, middle America, that's a lot of water, roughly two and a half times as much as the city of Chicago would get. Left unmanaged, that rainwater would turn the hillsides to mud and Machu Picchu would slide away. The Inca created a sophisticated drainage system. Inside the terraces, archeologists found a layer of rich topsoil. Under that, a layer of sandy dirt, and finally, gravel and larger stones. We could say that they are filtering galleries, meaning even when you get a lot of rain, the terraces never flood because the water is filtered through these progressive layers of material. Instead of racing down the mountain, the water slowly works its way into the ground. So there's almost no erosion. With this basic design in hand, the Inca fixed the first terrace into the mountain, then started on the next, replicating their way to the top. Once there, Inca engineers had to reckon with an even bigger water problem. This is a city paved with stone with few places for rainwater to go. But the Inca had foreseen that problem. And during construction, carefully placed more than a hundred drains throughout the city. Many of these drains delivered the runoff from the elevated parts of the city into the central plaza. Further digging there revealed a remarkable innovation to handle all of that water. Beneath the usual layers of topsoil and gravelly dirt, Wright's team hit a thick layer of white granite chips, the spoil from years of Inca stone cutting. In effect, what the Inca did was to build an underground drainage system, a type of conduit to carry water safely away. These were colossal earthworks, extending nearly 2.7 meters below the surface and encompassing several hectares. They collected water and shunted it away from the city. The Inca engineers spend about 50%, maybe 60% of their overall effort underground, doing foundations, site preparation to make sure that Machu Picchu would last forever. So as vast as the city appears, there's 60% more of it underground, holding it all in place. While the Inca went to great lengths to get rid of water, they also built fountains, which seem to celebrate it. There are 16 fountains in the city, each beautifully designed and a practical source of drinking water. The fountains are fed by a natural spring found nearby on the flanks of Machu Picchu mountain. From there, the Inca engineered a canal whose 3% grade was carefully crafted to deliver just the right amount of water to the fountains. Wright calculated the flow to be between 23 and 114 liters per minute, depending on the time of year, enough to sustain a population of close to 1,000 people. It was remarkable. It was something that created a great respect by us for the Inca engineers all those years ago. It is a respect also shared by Astete's team as they restore the Inca's original stonework. In spite of their lack of iron tools, the Inca were somehow able to transform granite, a notoriously hard stone. There's a clue to how they did this in Machu Picchu's quarry. We see here the basic method the Inca used to cut rocks. The idea is to create a neck in the block and then cause it to fracture. It was bone-jarring work. The technique the Inca used was direct hammering. With the rough blocks, they would start with a large tool like this one. As you can see, it shears very easily. Then they'd gradually use smaller and harder tools to give it that strong, smooth surface. Once the cutters had roughed it out, they put the stone on log rollers or mud and pulled it close to the construction site. The final step was to move the stone into place and match it to its mate. And here is the indentation they made, which matches the edge of the rock below it. It's held up by this wedge until they shave the two surfaces to match. Then the wedge is removed and the two stones fit together perfectly. Here, you can see the brace points they used to push the block up into place. They put beams here to lift the rock up. Once the rock was in place, these points were beaten, just as you see here and here in all these other rocks. That means that the finishing work was done at the site. We can see that this corner wasn't finished yet. All this portion was yet to be cut off in order to finish the wall. Driven by a royal mandate to build it here, Machu Picchu is a tribute to Inca engineering and artistry. Its hundreds of terraces buttress it from below. The granite walls are still solid after 500 years because of a remarkable drainage system. And it is crowned by an ingenious lacework of fountains, cascading from the mountain spring above. But why go to all this effort? Machu Picchu is in an unusual place to build, even for the Inca. Their capital, now modern-day Cusco, and other Inca towns like Pisac are in flatter, more accessible terrain. It's also remote, a five-day walk from the capital in Inca times. And today, it takes tourists four hours by train, followed by a harrowing bus ride up to the ruins. But throughout the site are hints why the Inca thought that this place was worth the trouble. In certain places, the Inca carved stones in the shape of sacred peaks surrounding the city, then displayed them like massive, holy icons. Even Bingham was struck by stones like this one, called the Sacred Rock, that mirrors the outline of Mount Yonantan directly to the northeast. In Inca times, visitors would approach Machu Picchu from above, where they could see the city as surrounded by the holy Urubamba River. For an agricultural people, there was nothing more important than water, and here was a place firmly in the water's embrace. There is one more piece of evidence connecting Machu Picchu to the sacred landscape. At the top of a pyramid-shaped peak within the complex is the sacred pillar known as the Intihuatana. This sacred pillar is in alignment with four mountain gods of supreme importance to the Inca, according to Johann Reinhard. The Intihuatana is situated such that it's at a high point in the center of the entire complex. But at the same time, it's the center of this massive landscape, because you have, in the far distance, these great snow-capped peaks, the highest ones in the entire region. They also happen to correspond to the cardinal directions. Its views to sacred peaks, proximity to the holy river, and the alignment with four powerful mountain gods must have made this location irresistible to the Inca. But how did the first Inca emperor, Pachacuti, actually use Machu Picchu? Within the city, there was a distinctive royal residence. It's located near the first fountain, ensuring that the king would have the purest water to drink. It's also close to the holiest temples. But whether the city was Pachacuti's royal court, a religious center, or a military post remains a mystery. A reanalysis of the skeletons that Hiram Bingham found suggests a possible solution. During Bingham's excavation in 1912, his team mistakenly identified these skeletons as the Virgins of the Sun. Recently, they've been reexamined. If we could identify who these people were, it might explain how Machu Picchu was used. During his study, anthropologist John Verano found no evidence of violent injury. So these weren't soldiers. He also confirmed that their burials had been simple, with no high-value artifacts. That meant they weren't royalty. In their bones, Verano found hints that they weren't common laborers either. Instead, they were from a class of people in between. I didn't see a lot of arthritis, even in the older adults at Machu Picchu. And that, again, made me think these are not people working really hard with, say, stone masonry or dragging rocks up the hills. So what were they doing here? In some ways, I guess you could see it as a big hotel staff, the caretakers and servants of the estate. This was a large staff. Verano ultimately identified the remains of 177 individuals. The evidence is strong that Machu Picchu was a royal estate for the emperor, Pachacuti. This would have been a peaceful retreat where he and his courtiers would have come to rest, worship, and enjoy themselves, their needs tended to by well-trained royal servants. And you can kind of imagine an entourage of the royalty coming from Cusco along the road, and everybody at Machu Picchu saying, whoops, let's get it ready, clean it up, and get food, and so on, and welcome our guests. But the new finds from the tombs at the nearby farming center of Parayacta don't seem to fit with this peaceful picture. The severe injuries in those skeletons suggest that Machu Picchu may have been connected to warfare. So how could Machu Picchu be a place of both war and peace? According to Spanish accounts, the Inca conquered this valley about a decade after Pachacuti came to power. So perhaps he built it as a way to seal his conquest. Incas were very skilled in psychological warfare, and they decide to build this magnificent estate on the hilltop that everybody living up and down that valley is gonna see from the first thing they walk outside their door to the last thing that they go in bed at night. That's a very powerful thing. It's a message of conquest and of possession, that they own that land and they control the people who live within it. So Machu Picchu was a formidable symbol of Inca power, a spectacular boast by Pachacuti, not just of their engineering prowess, but of their paramount link to the sacred mountains and rivers. Still, if this place played such a critical role in demonstrating the religious and military power of the Inca, why didn't the Spanish deface it as they did to other sacred Inca sites? And why isn't it ever described in any Spanish accounts? Part of the answer lies in the Corpus Christi procession back in Cusco, the annual festival that is a Christian revision of an Inca ritual. In that ritual, the Inca carried mummies instead of saints, especially the mummies of their kings. When Pachacuti died in 1471, he wasn't buried. He was mummified. The exact process is unknown. One theory suggests his body would have been gradually freeze-dried, left out in the searing sun by day, and alternately frozen at night. Through this repeated heating, freezing, and thawing, the corpse would have become completely desiccated. Curiously, this is similar to how the local Quechua people preserve llama meat. The result is jerky, which is one of the few Quechua words used in English. Once preserved, Pachacuti would not have been entombed. Instead, he would have continued to play an active role in the politics and rituals of the Inca world. Drawings made by the Incan artist, Guaman Poma, confirm the use of mummies in this way. We don't actually have a mummy of an Inca emperor, but we have descriptions of them. And we know that they were taken out during major festivals and paraded. We know that they had attendants who would shoo away the flies and give offerings every day, food offerings, and drink to the mummies. In other words, they were worshiped and believed to still play a role in the community. Care and handling of the mummy would have fallen to a group of family members called the Panaca, who also took control of all the king's royal estates. But over time, even Pachacuti's Panaca could have run short of resources. Work at Machu Picchu may have slowed, then stopped altogether. The descendants of Pachacuti had more pressing concerns. Even before the Spanish conquest, smallpox came. It was followed by a bloody civil war that left the Inca Empire weakened and fragmented. Barely 60 years after Pachacuti died, the Inca Empire finally collapsed under the Spanish invasion. When the royal families had lost their power, they were disorganized. There was civil war. There was massive destruction of sites. And the people at Machu Picchu probably at some point just said, well, nobody's coming to visit. And the site really had no reason to exist at that point. By then, it is likely that all but the royal servants had forgotten Machu Picchu. And after time, even they probably just drifted away. So the Spanish probably never heard about Machu Picchu and more importantly, never found it. It was for us, the luckiest mistake. It meant that Machu Picchu was left untouched, one of the only major Inca sites to remain intact. While it still poses confounding mysteries, it also holds great promise as new technologies and finds allow us to come to terms with the ghosts of Machu Picchu.