by Ashley Hamer Pritchard
September 1, 2026
On June 22nd, 1941, German mathematician Maria Reiche and American historian Paul Kosok stood on a massive plateau in the Peruvian desert, some 400 km (about 250 mi) south of Lima, as they watched the sun set over the horizon — and saw something that would change the trajectory of their lives.
They were here to study the Nazca Lines: mysterious designs etched into the ground in an arid stretch of desert undisturbed from the kind of rain and wind that might erase them from history. The lines date back to between 100 BCE and 800 CE, but weren’t discovered by modern scholars until the 20th century. Peruvian archaeologist Toribio Mejía Xesspe was the first to stumble upon the lines in the mid 1920s, but it wasn’t until the advent of commercial flight that the lines were appreciated in all their glory.
That’s how Paul Kosok first saw them — from a plane, after coming to Peru to study the irrigation systems of the Nazca region. A year later, he brought along his protégé, Maria Reiche: a German national with a mathematics degree who spoke five languages and had moved to Peru to be a tutor. On that plateau the evening of the winter solstice, the two watched as the kilometers-long line etched in the desert before them perfectly intersected with the setting sun.
A theory was born: These mysterious lines weren’t art or roads or irrigation ditches. They were an astronomical calendar — a giant chart designed to track the sun, moon, and stars.
Kosok and especially Reiche would spend the rest of their lives expanding this theory — and defending it, as new evidence continuously arrived to knock it down (and alien theories popped up to distract from the science).
We still don’t have a single, tidy answer for why the lines exist. But the evidence we do have points to a purpose much more grounded than a star calendar or an alien landing strip.
The Nazca Lines: Their Place, Culture, and Scale
The UNESCO protected zone here covers 750 square kilometers of desert — nearly the size of New York City. Officially, the site isn’t even called “The Nazca Lines”; its formal designation is the Lines and Geoglyphs of Nasca and Palpa, since it spans two separate Peruvian provinces.
The designs, known as geoglyphs, come in two main forms. The first is representational: depictions of animals, plants, people, and objects, some hundreds of meters wide, others much smaller. The second encompasses the lines: straight, unbroken grooves that run for kilometers in all directions, or large geometric figures, or lines that circle or radiate from a central location. A 2021 study counted 2,308 straight lines alone.
Considering the size of the site, you might understand why someone would invoke extraterrestrial influences: How exactly could a culture thousands of years in the past without the benefit of air travel or satellite imagery build such a thing?
The Extraterrestrial Theory
The man responsible for the idea that the Nazca lines were associated with extraterrestrial visitors may ring a bell to regular Skeptoid listeners: Erich von Däniken, father of the Ancient Aliens theory, who has appeared in 10 separate episodes, by my count. He wrote the book Chariots of the Gods?, first published in Germany in 1968, which laid out his theories about extraterrestrials assisting Earth civilizations, from the Maya to the Egyptians, in the construction of their monuments.
In the book, he writes,
Seen from the air, the clear-cut impression that the 37-mile-long plain of Nazca made on me was that of an airfield! ... What is wrong with the idea that the lines were laid out to say to the ‘gods’: ‘Land here! Everything has been prepared as “you” ordered’? The builders of the geometrical figures may have had no idea what they were doing. But perhaps they knew perfectly well what the ‘gods’ needed in order to land.
He goes on to say that the lines would have taken decades without modern technology, suggesting that instructions from an aircraft might have been necessary, and no one in their right mind would put in that much effort unless something as big as extraterrestrials visiting was at stake.
So how did they do all this without an aircraft? And did each image take decades?
How the Lines Were Really Made
The production of the lines themselves is simple: The desert surface is oxidized to a dark rust color, and just by removing surface rocks — or even running a finger through the sand — it will reveal the lighter colored sand below. Millennia of sunshine has darkened the uncovered sand over time, but not enough to fully erase the images.
Maria Reiche, the German mathematician who pioneered the astronomy theory for the lines, found that Nazca artists prepared their preliminary drawings on a smaller plot, around 2 m (6 ft) square. Many of these smaller draft drawings are still visible near larger images. From there, they plotted the lines with ropes stretched between stakes in the ground — straight lines were made with a rope stretched between two stakes, circles were traced by anchoring a rope to one stake, and more complex curves were drawn by linking partial circles together. There’s evidence of this too: you can still see stones or holes in the centers of many circles.
But then what? How did they turn the small sketch into a massive drawing? Reiche couldn’t figure it out, writing that they must have used some sort of instruments and equipment we don’t know about. Some scholars saw the Nazca’s history with weaving and assumed they used a similar grid system — mark a grid on the smaller image, mark off a grid many times larger where you want to create the full image, then copy the lines within each square exactly until you’ve filled the grid.
In 1983, renowned skeptic investigator Joe Nickell published an essay in the Skeptical Inquirer that demonstrated the answer. He wrote,
I decided to attempt to reproduce one of the larger Nazca figures — the 440-foot-long condor... using a means I thought the Nazcas might actually have employed. I was joined in the project by two of my cousins, John May and Sid Haney. The method we chose was quite simple: We would establish a center line and locate points on the drawing by plotting their coordinates. That is, on the small drawing we would measure along the center line from one end (the bird's beak) to a point on the line directly opposite the point to be plotted (say a wing tip). Then we would measure the distance from the center line to the desired point. A given number of units on the small drawing would require the same number of units — larger units — on the large drawing.
Instead of a desert plateau, he used a closed landfill in Kentucky, and instead of clearing gravel and sand, he marked the lines with white lime, the way you’d mark a football field. It took six of them nine hours to plot the large image, and after a week-long hiatus due to a challenge the Nazcas never faced — rainstorms — Nickell and his father spent most of a day marking out the final lines.
The work was a success, and Nickell concluded that the Nazcas almost certainly used this method. Considering it took six people two days to complete the drawing, there’s no reason to think that an otherworldly event would be necessary motivation.
Maria Reiche, the “Lady of the Lines” herself, gave another reason to doubt the alien airfield idea. She said, “Once you remove the stones, the ground is quite soft. I’m afraid the spacemen would have gotten stuck.”
Are the Lines an Astronomical Calendar?
Assuming the lines didn’t have an extraterrestrial explanation, we can now examine the first theory mentioned for the lines’ purpose: As an astronomical calendar that charted the movement of the sun, moon, and stars. This was the theory put forward by Reiche and Kosok: the lines recorded the passage of the seasons and tracked celestial cycles, and the images aligned with particular constellations: for example, an image of a spider was associated with Orion, and one of a monkey was associated with the Pleiades.
But more recent surveys have cross-referenced the positions of the lines with the movement of the stars and come up short. Most recently, a 2021 study published in the journal Applied Sciences ran all 2,308 lines against solstices, equinoxes, zenith passages, and star positions across the roughly 1,000-year Nazca period. It found that only 4% lined up with solar events, and star correlations were no better than chance. Sirius, the brightest star in the sky, had fewer hits than dimmer stars, which suggests these lines existed for a different reason than following the stars.
Water: The Leading Theory
If the lines weren’t a calendar, what were they? The leading answer today points to something a desert civilization would have been utterly obsessed with: finding water.
Nazca is in one of the driest places on Earth, and that early civilization relied entirely on runoff from the Andes Mountains and a network of underground aqueducts they built by hand. The supply of water was less than reliable, and a particularly dry season could force them to find other sources. Which is one reason anthropologist Johan Reinhard, who spent decades studying mountain worship across the Andes, argues that the lines were ritual pathways that led toward water sources in the mountains — mountains that the Nazca likely worshipped as living deities like other Andean cultures. Reinhard argued the straight lines pointed to water and the images served as pilgrimage route markers.
It’s also worth mentioning that mountains are a great vantage point for seeing the Nazca lines from above.
Physical evidence backs this water ritual theory: Worshippers regularly left ornaments crafted from sea shells as offerings on mountain peaks, and these same ornaments have been found on and near the lines themselves. And archaeological surveys have found that many of the lines were constructed near sources of groundwater, which may have provided better-quality water than rivers did.
New Research in a Millennia-Old Mystery
There’s still no smoking gun for the true purpose of the Nazca Lines, and researchers are still actively exploring the site. The latest study of the Nazca Lines, published in Proceedings of the National Academy of Sciences in 2024, used AI to find 303 new representational geoglyphs — a huge find, considering that it took nearly 100 years to find the last 430.
Earlier, I mentioned there were two types of geoglyphs at the site: straight lines and representational images that look like animals, plants, and objects. This study found that the representational images come in two forms, themselves: line-type and relief-type. Line-type geoglyphs are made the way we’ve already discussed, by clearing a continuous narrow path like a line drawing. Relief-type geoglyphs were the new discovery. They’re smaller, and made by clearing stones across the whole figure and its surroundings to create a shaded, filled silhouette. They average about 9 m (30 ft) across and are found mostly near walking trails, which the study argues means they were meant to be seen up close by people walking by. Another point for the water-pilgrimage idea.
Conclusion
The Nazca lines are an example of science done right — people examined the mystery; preserved the site; took the environment, culture, and human behavior into account; and formed theories that could be backed — or dismissed — by hard evidence. While there’s no definitive answer, the evidence points to a culture that understood geometry, organized labor at scale, and knew exactly what their survival depended on. Invoking extraterrestrial influence sells the Nazca culture short.
Whatever the lines’ actual message, one thing seems clear: they weren’t built for an audience in the sky. The rest is something we’re still learning to read.
