How did the Inca build Machu Picchu?

Scientists are still confused how Machu Picchu was built

Machu Picchu, the 15th-century Inca city high in the Andes, continues to fascinate experts with its mysteries. The methods used to transport and carve its massive stones—some weighing 15 tons—remain unclear. Theories range from hundreds of men dragging the stones to innovative techniques like using expanding wet wooden wedges for precision carving.

Meet Pachacuti, the king who built Machu Picchu

In the 1400s, King Pachacuti of the Inca Empire wanted a summer resort for himself, his family, and his entourage. So he and his builders set out to build Machu Picchu, a feat of engineering, carving, construction, and more. Its 700 terraces remain intact today, while its trapezoidal stones inspire construction efforts around the world. Learn about the fascinating process of building this wonder of the world here.

Machu Picchu, 101

Machu Picchu was built right on top of two intersecting fault lines, which makes it even more baffling how its temples and terraces have survived for more than 500 years—especially since no mortar was used to hold the precisely cut stones together. As this three-minute NatGeo video explains, this ingenious construction method allows the stones to bounce in place when earthquakes hit, shaking and rattling but rarely collapsing.

Machu Picchu is an ancient Incan citadel set high in the Andes Mountains in Peru, abandoned for centuries before its rediscovery in 1911.

Inca trail interactive map

Machu Picchu gets all the attention, but it’s definitely not the only Inca ruin in the area. Some dedicated trekkers opt to see the sites through a multi-day hike down the Inca Trail, which spans 26 miles from the Sacred Valley to Machu Picchu and reaches elevations as high as 13,800 feet above sea level. This 3D tour gives a sneak-preview of the ruins along the route, and the intense topography.

Sacsayhuaman, the Inca's largest structure

Less well-known but arguably more impressive than Machu Picchu is Sacsayhuamán, a 15th-century fortress-temple on the outskirts of Cusco. The site also features huge stones—some weighing more than 100 tons—carved into interlocking blocks and joined together through mortarless masonry. Archaeologists estimate it must’ve taken some 20,000 laborers to complete construction. This video offers a clickable 3D virtual-reality tour of the site.

The unsolved mysteries of Machu Picchu

Who lived there? How did they get all that granite up there? Who were the 100 bodies found buried here, and why did some of them have elongated heads? Explore eight of Machu Picchu’s unanswered questions while scrolling through panoramic, clickable street-view images of the site, in this guide from Google Arts and Culture.

Mapping tourism at Machu Picchu

Only 750 people lived at Machu Picchu at its height, but today, almost ten times that number trample through its delicate plazas and agricultural terraces every day. This data visualization vividly illustrates the skyrocketing numbers of visitors to Machu Picchu over the decades, and highlights the risks of over tourism, including soil erosion and other environmental threats, and negative social and economic impacts.

Machu Picchu before it was a tourist attraction

The Machu Picchu we know today is familiar thanks to its neatly manicured plazas, lovingly preserved stone buildings, and ever-present hordes of tourists. But that’s not what Hiram Bingham saw when Melchor Arteaga led him to the site in 1911. Back then, it lay covered by centuries of tropical overgrowth.

How the great city of Cusco came to be, according to the Inca

The chronicler Inka Garcilaso de la Vega recorded the origin story of the Inka (also spelled Inca) and the founding of Cusco, the capital of the society's great empire. Listen to the Inca origin story in this 4-minute video narrated by a child.

The US senator who found a city in the sky

Dr. Hiram Bingham, a Yale graduate and explorer, is credited with rediscovering Machu Picchu in 1911. Financially supported by his marriage to the Tiffany jewelry heiress, Bingham ventured into the Peruvian Andes in search of the lost Inca city of Vilcabamba. Instead, guided by local farmer Melchor Arteaga, he stumbled upon the awe-inspiring ruins of Machu Picchu.

Why did the Spanish steal the Inca's mummies?

From inside stone palaces and atop sacred mountaintops, the Inca dead continued to wield incredible power over the living. So much so that the Spanish confiscated them. Read more about the afterlife of these mummies here.

The Inca Empire: a timeline

When did the Inca Empire solidify into an empire? When was it invaded by the Spanish? What remains of it today? Click through this timeline to learn more.

What was the Great Inca Road?

In little more than 100 years, it grew from a small kingdom in the highlands of Peru to become the largest empire in the Americas. Read about the critical role played by the Great Inca Road.

A virtual reality experience of Machu Picchu

If you can’t make it to the Andes, this virtual-reality experience—created using 360-degree cameras, and 3D modeling and sound design—is the next best thing. It lets you explore all the site’s major landmarks, including the Sun Temple and the Temple of the Condor, while listening to the sound of the wind whipping through the ruins, birdsong, and audio commentaries from expert guides.

Human sacrifice in the Inca Empire

In the lands ruled by the Incas, mountain deities were well-respected and related summits were often selected as places for making the most important of all offerings — human sacrifices.

The last Inca grass suspension bridge in Peru

High in the Peruvian Andes, the aging Q’eswachaka bridge sags precariously over the Apurímac River. It has been built and rebuilt continuously for five centuries. Read more about it here.

Watch the annual three-day revamp of the Q'eswachaka bridge

Rebuilt every year since the Inca empire, this bridge still is used today by locals who want to traverse the 120-foot-wide gorge that runs beneath it. This three-minute video shows just how much effort goes into its restoration.

The decline of the Inca Empire

The Inca Empire was awash with gold, and the Spanish knew it. So what happened next? Read this BBC article to learn what happened during the last days of the Inca Empire.

How the Inca used threads to communicate

One of the great mysteries of ancient Peru is that the Inca did not have a system of writing, but communicated with a system of strings tied with knots. This 4-minute video explores its possible uses.

What was it like to rebel against the Inca Empire?

The Inca Empire grew to its gargantuan size and became the largest empire in ancient Americas through conquest, annexation, and arranged marriage, approaches that didn't always go over well with locals. Watch this five-minute video to experience a...

The explorer who re-discovered Machu Picchu

If there was a real-life inspiration for Indiana Jones, it may well have been Hiram Bingham, the Yale University historian who set out to find the rumored “lost city” of the Inca. This short feature from the BBC’s History magazine explains how this son of missionaries brought international renown to the site and to himself. In the process, he sparked an international feud that would last more than a century.

Yale returns Inca artifacts to Peru

From the time he came upon Machu Picchu in 1911, Hiram Bingham began removing artifacts and human remains from the site and bringing them back to Yale University. Yale's Peabody Museum held them for 100 years, despite demands by the Peruvian government and the public that they be repatriated. Finally, in 2011, Yale returned thousands of items, including ceramics, jewelry and human skeletons.

Inti, the Sun God of the Inca

The Incas were polytheistic, worshiping many gods, but Inti was the most powerful one in the pantheon. He was the god of the sun and also ruled over agriculture, fertility, and war. Inti was mainly a benevolent deity, though the Inca believed that solar eclipses meant Inti wasn’t pleased. To appease him, the Inca gave sacrificial offerings including food, white llamas, and even human beings.

The original article revealing Machu Picchu to the world

After first coming upon the ruins of Machu Picchu in 1911, Hiram Bingham’s subsequent expeditions were funded by Yale University, the Peruvian government, and $10,000 from a then-young National Geographic Society—in fact, it was the first archaeological grant that NatGeo ever issued. The magazine devoted its entire April 1913 issue, all 192 pages, to Bingham and his findings. You can read that issue in its entirety here.

Layers of minerals revealed by erosion give Vinicunca its distinct colorations

Located in Peru's Andean mountains, Rainbow Mountain is known for its vibrant colors, which result from layers of minerals such as clay, sandstone, argillite, and limonite exposed over millions of years by rain, snowfall, and strong winds.

The Inca's last stand against the Spanish

The Inca Emperor marched to meet the Spanish, expecting them to surrender. Spoiler: They didn't. Listen to this podcast episode to hear what led up to this moment and what happened next.

See a 3D reconstruction of Tenochtitlan, the Aztec capital

Mexico City today stands atop Tenochtitlan, the Aztec Empire's capital, founded in the early 1300s. This resource offers detailed 3D models and multiple visual perspectives of the ancient city—displaying its canals, grid layout, temples, and broader Mesoamerican cultural context.

Machu Picchu, sacred backdrop for your dating app pic

Anyone who’s been on Tinder or Hinge in the last decade has noticed it: the obligatory Machu Picchu selfie, almost as ubiquitous as those photos of men posing with a fresh-caught fish. How did Machu Picchu, of all places, become a dating-app cliche? This satirical essay from McSweeney’s doesn’t answer that question, but has a great time poking fun at it.

The Aztec capital fell after a brutal 75-day siege

The violent Spanish conquest ended with a 75-day siege of Tenochtitlan, where thousands died as Spanish forces and their Indigenous allies overwhelmed the city of 200,000. This animated explainer breaks down how those alliances enabled the empire’s collapse.

Engineering tall structures requires managing wind, earthquakes, and other destabilizing factors

Reinforced concrete, energy dampers, braced frames, flexible structures, and aerodynamic decks were among the methods implemented when building structures such as the Shanghai Tower, the Texas Super Skyscraper, and the South Rangitīkei Viaduct.

A Manhattan building doomed to collapse was saved in secret

After completing the Citicorp Center, its engineer realized that cost-cutting measures to use bolted instead of welded joints made the building vulnerable to collapse under quartering winds. For three months, crews worked in secret at night to reinforce the building under Project Serene.

Humans were forced to adapt to survive a supervolcano eruption 74,000 years ago

The Toba supereruption ejected 2800 cubic kilometers of ash, resulting in global cooling from blocked sunlight and acid rain. Archaeological sites show that humans developed bow-and-arrow technology to survive in arid conditions by fishing in seasonal waterholes.

Leaning Italian tower could fall after nine centuries

Italian officials have secured the area around one of two 12th Century towers in Bologna, fearing its leaning could lead to collapse. Could it fall? Read up on the city's efforts to secure it here.

Niagara Falls flows over 400-million-year-old layered rock

The falls cut through distinct layers of ancient rock: a hard cap of Lockport Dolomite sits atop softer layers of Rochester and Queenston Shale. This structure allows the falls to maintain a steep vertical drop as erosion undercuts the caprock.

Decoding the Indus Valley script

About 100 years ago, archaeologists uncovered an ancient city along the bank of the Indus River in eastern Pakistan that dated back to 2,500 BCE, though its urban planning, grid-like roads, brick-lined streets, multi-story homes, and sanitation and...

How did people survive the eruption in Pompeii?

In 79 CE, Mount Vesuvius erupted and buried Pompeii under roughly 20 feet of volcanic ash. This deadly eruption killed much of the city’s population, but archaeologists recently discovered evidence of survivors. In this podcast episode, classicist Steven Tuck challenges the popular belief of total annihilation and explains how people may have survived, and how they continued to live after the disaster.

Working conditions on the Panama Canal, built between 1904 and 1914, were abysmal, with thousands of workers dying on the job.

Before dynamite was invented, Erie Canal builders blasted rock with gunpowder

Constructed decades before the invention of dynamite, the Erie Canal’s toughest obstacles were blasted through using black powder charges.

Explore the world's most famous leaning towers and structures

Pisa gets all the fame, but the quirk of a tilt adds precarious charm to dozens of famous buildings around the world. There are Pisa replicas, but also old castle towers, crooked houses and tilted churches and mosques.

The century of the Panama Canal

The Panama Canal connects the Atlantic and Pacific Oceans through a 51-mile route that transformed global shipping when it opened in 1914. This breakdown covers how it was built, the workers behind its construction, and why its future may be challenged by climate and competition.

Ingenuity and advanced engineering have allowed trains to overcome extreme landscapes

The Jungfrau Railway utilizes electric trains powered by hydroelectric energy to ascend the Swiss Alps, while Poland's Elbląg Canal hauls ships along cable-powered tracks driven by waterwheels. Germany's Wuppertal monorail navigates bends as it glides over a river valley, and New Mexico's Holloman High-Speed Test Track can achieve speeds of Mach 8.6 for rocket sleds.

Roughly 25,000 workers died building the canal

For each mile of canal that was built, 500 workers lost their lives. The threats came from multiple fronts: mudslides, floods, earthquakes and disease-carrying mosquitoes. Workplace accidents became so common that artificial limb manufacturers competed for contracts with the canal builders.

Infrastructure projects in New York are much more difficult today

The Erie Canal was one of the most ambitious infrastructure projects in American history. Many have said such an effort would be impossible today. This article explores why that is the case and ponders the future of large-scale American infrastructure development.

Why Water Towers Are Built This Way

Essential pipes, sewers, and cables lie buried beneath New York City

The Department of Design and Construction offers a tour of its work sites, explaining the complex systems that exist underground. Gas, electrical, telecom pipes, and many others, sprawl out underneath the entire city, with dozens of maps that help workers know where they're placed. This layout is unusual compared to the rest of the country, where wires are often present and visible above ground.

Niagara's flow is changed artificially to accommodate tourists and power generation

The natural wonder is also the site of great engineering feats, from the Welland Dam that first allowed ships to travel from the upper lakes to the St. Lawrence Seaway, to one of the first hydroelectric dams.

See how the elite warriors of the Aztec Empire trained

This video explores the Aztec military’s elite Eagle and Jaguar warriors, known for their courage and combat skills, and highlights their rigorous training regimen. It concludes with a workout routine modeled on their methods.

Amateur engineers built America’s first great infrastructure project

With no engineering schools in the US, the Erie Canal was designed and built by self-taught amateurs who improvised new methods and became known as the “Erie School of Engineering.”

The mysterious qualities of obsidian and magnetite

Obsidian is a dark volcanic glass created when lava cools quickly and frequently contains magnetite, a key early mineral used in compasses. Large deposits were discovered and used in central Mexico by the Toltecs roughly 1,000 years ago at the ancient site of Teotihuacan. This essay explores obsidian's cultural impact and the mysterious presence of magnetite in migratory birds.