Machu Picchu, 101

How did the Inca build Machu Picchu?

How did the Inca, a people without iron or steel, build a city that has withstood hundreds of years of earthquakes and inclement weather? Machu Picchu stands atop steep landslide prone slopes and active fault lines and gets up to 80 inches of rain...

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.

Machu Picchu explained

High in the Andes Mountains, Machu Picchu stands as a testament to the ingenuity and resilience of the Inca Empire. Constructed in the mid-15th century during Emperor Pachacuti’s reign, this site is believed to have served as a royal retreat or ceremonial center. Its engineering marvels, including sophisticated aqueducts, terraced farming systems, and precisely carved stone structures like the Sun Temple, highlight the advanced skills of the Inca civilization.

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.

The ancient engineers inspiring modern building practices

Modern concrete structures need replacing every 50 to 100 years, so why are buildings by the Maya, ancient Rome, and ancient China still standing strong? This article details how scientists are looking into humanity's past for clues on how to craft long-lasting structures. Part of the problem is adopting old material recipes to hold up to modern demands.

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 are ancient ruins underground?

When cities fall into disrepair, it's often easier to flatten what you can and build on top. This is why modern archaeologists frequently discover ruins underground, revealing generational layers of cities rebuilt over time. This video explores major examples of this principle, from ancient Troy to even modern Seattle.

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.

See ten of the most amazing Mayan ruins

Hidden beneath the jungles of Mexico’s Yucatán Peninsula, Maya temples, pyramids, and cities reveal the civilization’s vast construction ambitions. Decades of archaeology have uncovered these sites, which are explored in detail in this guided video tour of 10 significant ruins.

Stonehenge, explained

Located about 90 miles west of London, Stonehenge was built around the same time as Egypt’s Great Pyramid. Its 30-ton stones have fascinated archaeologists and historians for centuries, making it one of the world’s most studied prehistoric sites.

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.

See a 3D reconstruction of Tenochtitlan, the Aztec capital that was home to an estimated population of 200,000 to 400,000.

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.

A look at some of the world's most unique churches

From a skeleton-adorned church in the Czech Republic to wooden churches built without nails in Russia, this video explores some of Christianity's most intriguing architectural feats. These places of worship were built in remote areas throughout history, and show amazing innovation. See a fascinating glimpse into the overlooked structures, along with stories of how and why they came to be.

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.

Counterweights can dampen the impact of seismic activity on buildings

Japan’s Tokyo Skytree uses a free-moving central column inspired by ancient pagodas, while Taiwan’s Taipei 101 contains a 660-ton pendulum on its 92nd floor that swings out of sync with the building.

View a map of the world’s major earthquakes from 1956-2022

Such maps can help identify tectonic plate boundaries. The most significant earthquakes are characteristic of converging plates, such as those in the Circum-Pacific Belt and the Alpine-Himalayan Belt, where the Himalayas continue to grow.

Explore the archaeological treasures of Pompeii, the city buried under volcanic ash when Mount Vesuvius erupted in 79 CE.

In 1963, a basement renovation in Turkey revealed a passageway to a hidden, multilevel underground city that once housed as many as 20,000 people

Driving the 99 bends up China's Tianmen Mountain Big Gate

A huge rock gate sits atop a mountain in China's northwestern province of Hunan, where visitors climb 999 stairs to crest the natural wonder. For years, tourists used a cable car to reach the top, but a thrilling, curvy road was built in recent decades to allow for better access—and has become an attraction in itself.

Meet a 90-year-old who built his own hobbit-inspired house

A retired carpenter built himself a kind-of Hobbit house, and is living comfortably off the grid at 90 years old, tourists notwithstanding. Learn how he did it with this video.

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.

Inside the most crowded place on Earth

Once the densest place on Earth, Kowloon Walled City was a chaotic labyrinth of stacked homes, hidden corridors, and thriving underground life.

Black Rock City is a remarkable portable town

While Burning Man hosts many impressive and unique architectural feats, these buildings also have notable issues of safety, accessibility, and reliability.

Massive 3D printers have been used to build homes by stacking layers of 'concrete toothpaste,' a fire-resistant material that effectively insulates against outside noise.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

See photos of Meteora, a mountainous site in central Greece, home to 14th-century monasteries perched atop soaring outcroppings.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

Waves off the coast of Nazaré, Portugal, can reach over 100 feet and are caused by the area's deep underwater canyon geography

In 1984, Operation Smash Hit intentionally crashed a 239-ton train into a nuclear waste canister at 100 miles per hour to prove the canister's safety, which remained completely intact and lost just 0.29 of its 100 pounds of pressure.

Explore fun facts from the USPS, including unique post office buildings, a stamp that traveled past Pluto, and more.

Frank Lloyd Wright's houses are historically hard to sell because they're old, subject to local landmark commissions, and often unfashionable

In 2018, 26-year-old missionary John Allen Chau was killed by tribesmen after attempting to reach and evangelize on India's isolated North Sentinel Island

When you complete a CAPTCHA on a website to prove you are human, you may be unknowingly training algorithms for self-driving cars, whose systems require training data to help identify crosswalks, bicycles, and other outdoor objects.

Explore an interactive map built from more than 100,000 survey responses on where people find joy in their lives

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.

Exploring the Larry Bird punch that almost changed March Madness

The first horror movie is believed to be George Méliès' 1986 short 'The Haunted Castle,' which pioneered the use of special effects

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

See how fireworks are made and learn how metals like magnesium and copper are responsible for different colors.

A 2019 Facebook event called on attendees to "Storm Area 51, They Can't Stop All of Us," resulting in countless memes, the creation of a music festival, and eventually the arrests of those who did try to approach the area.

For centuries, it was common to sleep in two shifts: a few hours at the beginning of the night, and a longer period beginning around midnight

According to the physics of black holes, our 4D reality may be a hologram—a projection of information coded on a 2D surface on the edge of the universe.

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

Despite being favored by 87% of Americans, Congress does not have term limits.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.