Southwest Costa Rica, 1939.
Workers with the United Fruit Company
begin clearing the rainforest near the Diquis Delta
for a new banana plantation.
While making their way through the dense vegetation,
the workmen find dozens of giant stone spheres.
They started to find these massive stone spheres
that they had no clue why they were there.
The instruction for them was, if you find anything, just move it.
And they just started to move them.
But they just kept appearing.
NARRATOR: In 1943, the archeological journal
published photos of the mysterious spheres,
which caught the attention
of American archaeologist Dr. Samuel Lothrop.
Five years later, Dr. Lothrop led an excavation of the area
and discovered hundreds of stone spheres.
They range in size from just a few inches
to more than six feet in diameter,
and weigh up to 15 tons.
Archeologists soon discovered stone spheres
throughout the Diquis Delta, and on the nearby Isla del Caño.
Many were found with artifacts from
the ancient Indigenous Diquis culture,
and are believed to be at least a thousand years old.
About 300 have been discovered so far.
Some of them are fairly small, like the size of footballs.
Others are huge,
between eight and nine feet tall and wide.
Some have carvings on, like spirals...
...and what looks like boats or ships.
They look like they're created in a machine.
NARRATOR: Researchers believe the stone that the spheres are carved from
is not local to the Diquis Delta,
but was transported from a quarry
that was located more than 50 miles away.
CARRANZA: The quarries of this material
are allegedly found at least
a few dozen kilometers from the site
where the spheres are located.
So that brings us questions of transportation.
Walking around the rainforest is not an easy task.
You have creeks, you have mountains, you have hills,
you have branches, you have tree roots.
So how were they moved?
NARRATOR: Just as puzzling as how the massive objects were moved
is how they were made.
Archeologists believe that the Diquis civilization
carved the spheres with simple stone tools.
But some researchers argue that creating
such a precise shape would be difficult to achieve,
even with today's technology.
WHITEHILL: It's important to note that these are,
in some reports, granitic, which are very,
very hard rocks to shape, to form, to move,
and to quarry in any capacity.
If we wanted to make these same spheres,
we would need something harder than granite.
And there are very few substances that are harder.
JIM VIEIRA: What's noteworthy is some of them are
almost perfectly spherical.
And that's a very tall task
to create that with the tools of the time.
As a stonemason, I would use diamond saws,
I would use polishing items.
But when you look at Indigenous people
that were purported to have made them,
did they have those machines, did they have that equipment,
did they have that technology?
NARRATOR: How could a culture that only had access
to stone chisels and rudimentary tools have carved
and transported such enormous stone spheres?
And what could have been their reason for doing so?
CARRANZA: Since the United Fruit Company
started moving the spheres,
we do not know the original location of most of them.
You start to wonder, what if we could go back in time
and see the exact location of all the spheres?
What would they show? Would they show a pattern?
Would they show a constellation map?
Would they be like the Nazca lines?
Like a pattern that you could only see from above?
NARRATOR: Although documentation to explain the spheres
does not exist, according to local legend,
they were created by the gods.
HENRY: One very interesting explanation for the Costa Rica spheres is
that they were created by Tara, the god of thunder,
who used some sort of a blowpipe to shoot these spheres
out of the pipe in order to push back hurricanes.
Ancient astronaut theory says that within legends like this,
there's often a kernel of truth.
And so you have to wonder,
is this a calling card
from some extraterrestrial entity,
a sky god, Tara, with some sort of message?
TSOUKALOS: To me, the ancient legend of the god of thunder illustrates
an example of misunderstood technology.
Clearly those spheres themselves never descended from the sky.
But maybe our ancestors saw
the appearance of a spherical craft by the extraterrestrials
who visited us thousands of years ago.