(narrator) On a pullout off Route 95, just west of the California/ Arizona border, there's an ancient treasure that most people never notice.

That's because to truly appreciate it, you have to view it from above.

But the Blythe Geoglyphs were carved into the soil long before air travel was invented.

So who were they made for?

[ethereal music] Meet Alfredo Acosta Figueroa, a Chemehuevi elder and self-taught historian.

Alfredo has spent the better part of the last six decades studying and fighting to protect this collection of ancient rock paintings on the desert floor between Los Angeles and Phoenix.

The three human figures and two animals that make up the Blythe Geoglyphs, or Blythe Giant Intaglios, were made by scraping away the darker surface desert rocks to reveal the lighter-colored stratum underneath.

Look at this very leggy boy.

There are hundreds of such geoglyphs throughout the Southwest, but this collection is by far the largest in number and size.

And I mean really large.

This one right here, it's 171 feet long.

That's half the length of a football field.

Archaeologists and historians disagree on who made these carvings and to what end.

In fact, it's not even clear exactly when the glyphs were made.

Radiocarbon dating, a process which measures the age of an object by its content of carbon 14, shows the carvings could be between 450 and 10,000 years old.

That's a fairly imprecise date.

And that's because radiocarbon dating works best to measure the age of formerly living things, like plants and animals.

Despite long-standing knowledge of the glyphs by local tribes, a pilot named George Palmer is often credited with discovering the glyphs when he flew his plane over the area in 1932.

(Figueroa) The Mojave oral history and the Chemehuevi oral history identified a lot of the geoglyphs that we have here, different versions but all related to the creation story.

(narrator) For as long as humans have been on Earth, we've struggled to understand who we are and where we come from.

We even gave this quest its own scientific discipline.

Cosmology is the study of the origin, the evolution, and the fate of the physical universe.

It's the place where science and philosophy meet.

And while some scholars credit Einstein with formalizing the field of study in the 1920s, ancient communities worldwide have always grappled with understanding their place in the universe.

Since written language only developed about 5,000 years ago, we can't read accounts of this study.

But images like the Blythe Geoglyphs give us clues into the philosophies of ancient peoples.

Alfredo believes the glyphs are evidence that this region is the birthplace of the Aztec culture, Aztlán.

The Aztecs ruled a large swath of Mesoamerica from the 14th century until 1521.

Many folks today consider Aztlán to be a mythical place.

But myths often contain clues into past truths.

And things we hold to be true today might later be viewed as mythical by some future dominant culture.

(Figueroa) The United States government, with its original Manifest Destiny, came and said, "From sea to shining sea is ours."

So they refuse to accept these truths.

(narrator) Alfredo wrote and self-published a book comparing the glyphs and other local landmarks, like the shapes of the rocks in the local mountain range, to the images found in ancient Aztec codices.

Codices are ancient manuscripts.

The codices that Alfredo has been studying contain details of all aspects of Aztec life, including their history, scientific beliefs, and origin story.

(Figueroa) The natives here are so fortunate that we have codices.

They relate to the story of the creation.

(narrator) Alfredo isn't the first to say that the region was once Aztlán.

The Treaty of Guadalupe Hidalgo map that was created at the end of the Mexican American War in 1848 clearly labels the Ancient Aztec Residence near the Colorado River just outside what is now Blythe.

While there's no scientific consensus on where or even if Aztlán ever existed, the Blythe Glyphs are one of many geographic mysteries that populate the Earth.

And if no one knows who made something, who decides how and if it gets protected?

(Figueroa) In the old days, it used to look like a blackboard.

But now we have roads all over.

(narrator) Alfredo has made it his life's mission to keep the glyphs and the land that surrounds them from suffering from further damage.

Over the course of many years, he's fought to prevent the construction of a nuclear power plant and a nuclear dump.

But his latest battle is with solar companies.

Since California passed an aggressive carbon-reduction law, Alfredo and a group of people from the Lower Colorado River Tribes have been fighting to prevent the construction of dozens of solar projects in the desert.

(Figueroa) Solar energy is the father of the creation.

We're not against solar power, but where it's put is a different story.

[singing in Spanish] ♪ (Figueroa) They do not have to be destroying sacred sites or sacred land.

[singing in Spanish] (narrator) Places like the Blythe Glyphs encourage us to continue to seek a better understanding not only of who we were, but who we are today.

(Figueroa) The three main questions have always been, where did we come from?

Why are we here?

And where are we going?

Why are we here relates to that we have to make this harmonious balance among all things.

We do all for the benefit of all-- different sizes, different shapes, but all together in the trunk of the human race.

Accessibility provided by the U.S. Department of Education.

[ethereal music] ♪ Hey, guys, Joe here.

The team had such an amazing time bringing you this story.

These are the stories that Overview is about.

Let us know what you thought down in the comments, or if you have any other ideas of amazing stories that we should bring you from our unique perspective.

All right, we'll see you next time.