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High in the Andes Mountains of Peru lies one of the world’s most famous archaeological sites.
It was built by a civilization without iron tools, wheeled transportation, or a conventional writing system, yet its builders created extraordinary stonework, terraces, fountains, and drainage systems on a steep mountain ridge.
For centuries, it remained largely unknown beyond the surrounding region before the wider world learned of it in the early twentieth century.
Learn more about Machu Picchu on this episode of Everything Everywhere Daily
Machu Picchu gained international fame in 1911, when a Yale expedition led by Hiram Bingham brought the site to global attention. Yet, Bingham wasn’t looking for Machu Picchu. He stumbled across it by accident.
His real target was Vilcabamba, the legendary mountain refuge Manco Inca founded in 1539 after his failed siege of Cusco. Bingham, like other treasure hunters, expected the stronghold to hold vast amounts of gold.
For more than three decades, four successive rulers waged guerrilla resistance from Vilcabamba until Spanish troops captured and executed Túpac Amaru, the last Incan emperor, in 1572.
The Spanish burned the jungle city, leaving it swallowed by vegetation and fueling the legend of the “Lost City of the Incas”. This was the prize Hiram Bingham was actually looking for.
While earlier explorers relied on colonial maps or sheer luck, Bingham, trained as a historian, took a different approach: he actually talked to locals.
He followed their oral histories and even hiked with anyone willing to guide him.
On July 24, 1911, Bingham met Melchor Arteaga, a Quechua-speaking farmer living along the Urubamba River valley. Without Arteaga, Bingham likely would have hiked right down the valley floor without ever knowing what was at the top of the ridge.
Arteaga had lived in the valley his entire life, farming a modest plot and selling supplies to travelers. Through an interpreter, Bingham asked about local ruins.
Arteaga didn’t hesitate: high atop the mist-shrouded ridge opposite his hut lay magnificent stone palaces and terraces.
Arteaga pointed up toward the ridge between two jagged summits: Huayna (WHY-nah) Picchu, which means the young peak, and Machu Picchu, which means the ‘old mountain.’
While Bingham’s skeptical companions stayed behind, Bingham offered Arteaga one silver sol, or about fifty cents, to guide him to the ruins.
Thankfully, Arteaga took the deal.
Arteaga led Bingham and an armed escort across a terrifying footbridge of logs lashed with vines over raging rapids, with Bingham crawling across on hands and knees. The group hiked for nearly four hours through more than two thousand vertical feet of snake-infested cloud forest.
At the saddle between the peaks, they found local families farming the terraces, seemingly oblivious to what was above them.
Arteaga rested while an eleven-year-old boy, Pablito, guided Bingham through the final bamboo thicket to the citadel.
Emerging into the clearing, he was stunned. He later recounted his amazement in his journal: “It fairly took my breath away. What could this place be? Why had no one given us any idea of it?… The sight held me spellbound… I could hardly believe my eyes.”
Bingham was convinced he had found the lost Incan city of Vilcabamba.
In an incredible twist of historical irony, Bingham actually walked right through the ruins of the real Vilcabamba barely a month after visiting Machu Picchu.
Unimpressed by its modest stone dwellings and overgrown brush, he dismissed it as an insignificant outpost, refusing to believe the legendary rebel capital could be so ordinary after seeing Machu Picchu.
Yet despite the wonders he saw, Bingham spent only a few hours taking notes and pictures at Machu Picchu before moving on in search of Vilcabamba, which he believed was deeper in the jungle.
In an era before Howard Carter found King Tut, Machu Picchu was a massive archaeological discovery.
Or perhaps ‘rediscovery’ is the better word, as Bingham didn’t discover the site. Local farmers had known about it for years; they didn’t tell anyone because no one had asked.
Nonetheless, Bingham was determined to amplify what he had found.
When he returned to the United States with pictures in hand, Bingham pitched National Geographic editor Gilbert H. Grosvenor and secured a landmark ten-thousand-dollar grant matched by Yale University.
Bingham agreed that National Geographic received the first rights to publish the expedition’s official findings and photographs.
In April 1913, National Geographic dedicated an entire monthly issue to a single topic for the first time.
Filled with nearly 250 photographs, that single issue turned Machu Picchu into a household name.
Despite having nearly every issue of National Geographic from the last 125 years, I don’t have this issue, and it is very hard to find. I check eBay every other day, and I almost never see it listed.
Yale wanted to expand the holdings of its Peabody Museum of Natural History with artifacts from Bingham’s expedition.
Bingham returned to the Urubamba Valley in July 1912 to lead a major archaeological and historical study.
The $20,000 in grants gave him unprecedented resources, which he dedicated to removing centuries of forest buildup at the site. As the team cut back the jungle each day, they made astonishing discoveries.
They revealed a granite city complete with fountains, plazas, and ceremonial spaces. The excavation revealed more than stone structures; the team found pottery, bronze tools, and more than 170 ancient skeletons buried in caves in the cliffs.
Yale bone archaeologist George Eaton erroneously claimed most of the bones were female, leading Bingham to conclude the site was a religious sanctuary for the sacred “Virgins of the Sun.”
Known in Quechua as the Acllakuna, or “Chosen Women,” the Virgins of the Sun were an elite class of young women selected from across the empire to serve the state religion and the royal court.
Raised in dedicated sanctuaries under a vow of chastity, they wove the empire’s sacred textiles and brewed ceremonial maize beer. They were frequently betrothed to nobles or allied chieftains to seal imperial alliances.
However, Bingham’s theory was wrong. Later DNA tests showed the skeletons were a 50-50 mix of men and women, not the domain of the Virgins of the Sun.
Despite the errors, the physical work accomplished that summer was undeniable; they had reclaimed the site from the jungle.
In the process, National Geographic got its iconic photographs, and Yale received tens of thousands of ancient artifacts. These artifacts remained in Connecticut for nearly a century before finally being repatriated to Peru in 2011.
Since Bingham’s rediscovery and the 1913 issue of National Geographic, researchers have spent more than a century debating Machu Picchu’s true purpose.
Bingham clung to his twin theories that the site was either Vilcabamba or a sanctuary for the Virgins of the Sun, until he died in 1956.
Modern researchers, however, have thoroughly dismantled both theories.
Today, the consensus holds that Machu Picchu was an elite royal estate built around 1450 for the ninth Inca emperor, Pachacuti.
Set in the warmer cloud forest below Cusco, it served as a seasonal retreat where the sovereign and his royal court could escape harsh Andean winters, hunt, feast, and entertain regional leaders.
Evidence also points to an astronomical observatory at the site, as stone markers operated as precise solar sundials that tracked solstices and agricultural cycles.
Machu Picchu’s dramatic placement within a sacred Andean landscape suggests it was also a major ceremonial center.
Rather than serving a single narrow function, Machu Picchu is now believed to be a multi-layered imperial masterpiece: part royal retreat, part political showcase, and part sacred ceremonial sanctuary.
While the purpose of Machu Picchu has inspired debate, civil engineers have been fascinated by how the Inca built it. Planning a site 8,000 feet above sea level on a seismically active ridge that receives more than 80 inches of rain per year presented serious challenges.
The Incan Empire’s technological capabilities made things even more difficult.
Before Europeans arrived, the Americas had no beasts of burden capable of hauling heavy loads. No oxen or horses could drag the enormous stones to the top of the site.
The site was a natural quarry, which made gathering the granite easier, but the large stones still had to be moved significant distances without the technology of the wheel.
Inca builders had no written alphabet to formalize designs, as administrative record-keeping relied on the quipu system, a series of different-coloured knotted ropes.
Overcoming these obstacles required a massive workforce, mobilized through the mit’a system—the Inca’s mandatory labor tax owed by every household to the state.
The single greatest threat to Machu Picchu was water.
Without an ingenious drainage network to divert the torrential rains the site recieved, the complex would have collapsed into mudslides, washing the entire citadel into the canyon.
Solving this problem required engineers to build 129 drainage outlets that carried water safely down to the valley below through a sophisticated network of terraces covered with topsoil and gravel.
Terracing had a long history in the Incan Empire. It was the key to their agricultural system, and repurposing it at Machu Picchu was a natural extension of the technology
As impressive as Incan hydrology was, the stonework is even more impressive. Bingham praised Incan stone masonry throughout his career, but in his book, Lost City of the Incas, he noted:
“The flowing lines, the symmetrical arrangement of the ashlars, and the gradual gradation of the courses, combined to produce a wonderful effect, softer and more pleasing than that of the marble temples of the Old World. Owing to the absence of mortar, there were no ugly spaces between the rocks. They might have grown together. On account of the beauty of the white granite, this structure surpassed in attractiveness the best Inca walls in Cusco. Dimly, I began to realize that this wall and its adjoining semicircular temple over the cave were as fine as the finest stonework in the world.”
Mortar was the conventional solution to the problem facing Incan engineers, but they clearly understood they were building in an earthquake zone and that the stones needed to move.
Engineers have praised the stonework, as the region has been struck by earthquakes since its construction, and the stones have danced and shifted as they were supposed to, allowing the stone structures to survive for centuries.
The site’s long-term damage came from jungle encroachment rather than seismic activity or structural flaws.
Remarkably, Incan stonemasons cut the stones with such precision without iron or steel tools. Masons drove dry wooden wedges into natural fissures and soaked them with water; as the wood absorbed the moisture and expanded, the outward pressure cracked the granite along clean fracture lines.
Archaeologists have reverse-engineered these practices using hammerstones found at the site. More than 500 years later, the stones at Machu Picchu are still so tight that neither a knife blade nor a sheet of paper can slip between them.
To bring water to the ridge, Inca engineers tapped a high-altitude spring and built a gravity-fed canal that delivered a constant stream into the citadel.
Known as the Stairway of the Fountains, these sixteen cascading basins provided water to the site for both practical and sacred purposes.
Historians long debated why Machu Picchu was abandoned, but the modern consensus points to a tragic end. Occupied for less than a century, the estate was abandoned in the 1530s during the chaos of civil war and smallpox epidemics that preceded the Spanish conquest.
Machu Picchu was designated a UNESCO World Heritage site in 1983 and voted one of the New Seven Wonders of the World.
Today, more than 1.5 million travelers make the difficult trek up into the cloud forest every year.
Machu Picchu endures because it is more than just a spectacular collection of ruins. It is a monument to Inca engineering and political power.
Hiram Bingham did not truly discover Machu Picchu, but he did introduce it to the wider world, beginning more than a century of research that continues to reshape our understanding of the site. Even today, after decades of excavation and study, Machu Picchu still retains some of the mystery that made it famous in the first place.