NARRATOR: Palmar Sur, Costa Rica.
While clearing the jungles in the 1930s,
crews discover hundreds of monolithic stone spheres.
DAVID CHILDRESS: Many of them are huge.
They're 10 feet in diameter.
They're gigantically huge.
Others are much smaller, the size of a basketball
or of a car tire or something like that.
NARRATOR: To date, over 300 stone
spheres have been found at archaeological sites
across the region.
And Las Bolas, as they are called,
are some of the most precise stone
carvings in the ancient world.
Some experts believe these mysterious stone balls could
be 96% completely spherical.
DAVID CHILDRESS: A perfectly spherical
round ball is hard to make.
And in fact, where they're found is a primitive area.
So the stone balls that we see at Costa Rica
would have been very, very hard to make
by just bashing them out with a rock.
It almost seems like there was some kind
of megalithic carving school.
Who could create the most perfect sphere?
Some of them are still hidden within the jungles.
So what were they doing there?
Why were they constructed?
DAVID CHILDRESS: Jungle dwelling local chiefs
were sometimes buried with some of the smaller balls.
But some of the balls are gigantically huge.
In fact, they're so large, they couldn't fit in any grave.
So the great mystery with the stone balls
really is what their purpose was.
GIORGIO A. TSOUKALOS: According to the legends of Costa Rica,
those stone spheres were used as cannonballs
by the god of thunder to drive away
the god of wind and hurricanes.
Now, these are all wonderful ideas of a story.
But as we all know, every story has a core of truth.
And the question is, what is that core?
NARRATOR: Are the legends of gods battling storms really
a description of ancient astronaut machinery at work,
as some researchers suggest?
And if so, might the discovery of stone
spheres reveal the ultimate purpose for monoliths?
Bosnia-Herzegovina, 2004.
A team of archaeologists discover
stone spheres in forests and creek beds
near the town of Banja Luka.
DAVID CHILDRESS: If you go into that area,
it's a ravine in a mountainside that's been cut by a stream,
and in it are all of these stone balls, very similar to the ones
in Costa Rica.
They're half buried in this mountainside.
And some are exposed.
It is a tourist area.
And in fact, Bosnia has four or five areas where
these stone balls can be seen.
The tree was standing there.
But in the last storm, the tree fell,
and all this dirt, all this material
covered with [inaudible] here, which is here, right here.
The biggest source of Bosnian stone spheres
is the central Bosnian town of Zavidovici.
We took samples from four different stone
spheres and samples of natural stones that we found nearby.
And then we did chemical analysis.
And the conclusion was the stone spheres were
made from the liquid state.
They would melt them.
They were adding certain additives to get the better
properties of material.
And then when they got dry in certain molds,
they were getting a perfect shape of the sphere.
NARRATOR: Like most other monoliths,
researchers believe the spheres were likely
used for ceremonial rituals.
But is it possible that these monoliths, like the stone
spheres in Costa Rica, helped create
a connection to celestial beings,
as ancient astronaut theorists contend?
DAVID CHILDRESS: Another theory of the stone balls
is that they were somehow used as star maps,
and that they were rolled around,
and they would show where stars were,
and their relationship to other areas, very much
like some extraterrestrial map.
PHILIP COPPENS: It's also said that these stone balls were
there to concentrate thought, that they were somehow
physical devices, that somehow by touching or working
with these stones, were able to establish
a bridge to another dimension.
And so we might actually be looking at a civilization who
realized that the places where these stone spheres were
located were somehow power spots,
that somehow there was some form of energy whereby if we were
able to concentrate, we would indeed
be transported to a world where we could
communicate with the gods.
And that might be why these stone spheres are
located in the places they are.