NARRATOR: Tulum, Mexico-- here, on the eastern edge
of the Yucatan Peninsula, lie the ruins
of one of the last cities built by the Maya.
Behind me is the Temple of the Diving God.
And the western doorway is a stucco relief
of a winged being, who is either diving
down from the sky or he's diving down into the water.
His real identity is not known.
NARRATOR: In addition to the diving god,
it has been documented that the interior of the temple
once contained a mural portraying the Aztec water
goddess, Chalchiuhtlicue.
While the Aztecs did not occupy the Yucatan Peninsula,
their ancestors, the Olmecs, did.
And some believe there may be a profound connection
between this area of Mexico and the Aztec water
gods, who ruled over a paradise-like world called
Tlalocan.
Descriptions of Tlalocan come from the Aztec shamans--
spiritual guides who could access this other-worldly realm
through whirlpools while in a dream state.
There's an intriguing site right here off the coast
of the Caribbean Sea.
And it may have a connection to the Aztec Tlalocan.
And its name is Cenote Angelita.
And it's right here.
NARRATOR: A cenote is a sinkhole where
limestone bedrock has collapsed, exposing
the freshwater underneath it.
Many of the cenotes in this part of the Yucatan
are believed to have been formed by the meteor
strike that wiped out the dinosaurs
more than 65 million years ago.
As a result of this extreme impact,
they contain high amounts of shocked quartz.
Shocked quartz is a particular type
of quartz that really needs very,
very high pressure to form.
Quartz is a crystal.
But every crystal is not completely uniform.
It's comprised of smaller little pieces that
have to align along defect.
And high pressure changes the internal structure
of the quartz.
NARRATOR: Scientists have long known that quartz
is able to convert the earth's natural electrical vibrations
into a form of energy.
And some have even suggested that it could be used
in the formation of wormholes through
an electromagnetic reaction called the Casimir effect.
The idea is, if I take two metal plates
and stick them in the vacuum of space,
it turns out, because of quantum fluctuations,
this creates an effective attractive
force between the plates.
One can think of this as a negative energy.
Now, an intriguing idea that we get
is that this is exactly the principle
we need to understand perhaps how to stabilize a wormhole.
NARRATOR: Although there are a number
of cenotes in the Yucatan, Cenote Angelita is very unique.
About 100 feet below its surface,
the freshwater meets up with the salt water coming
from the ocean beneath it, creating
a mysterious underwater river.
David Childress has enlisted diver Spencer Stander
to help him explore the cenote.
We'll see the river around an island.
And you'll see these bizarre trees.
It's like a decrepit forest.
It's so cool.
It looks like a moving river.
You're going to be blown away.
NARRATOR: Although the waters of the cenote
are extremely murky on the surface, at 15 feet down,
everything becomes crystal clear.
But once they descend to 100 feet,
it turns as black as the darkest reaches of space.
And even though we had lights with us,
it was still like we were floating within the cosmos.
But then as we got down at 100 feet,
suddenly we could start to see the sides of the cenote.
NARRATOR: Here, the freshwater of the cenote
meets the salt water of the ocean,
forming one of nature's most mysterious anomalies--
an underwater river.
It is here that some ancient astronaut
theorists believe there may really exist
a portal to another world.
It can't be a coincidence that both Mayan and Aztec beliefs
incorporated a swirling pool of water
where they were able to travel to some other sacred paradise.
Maybe we're talking about a form of technological travel
that isn't understood in modern form.
But through the ancient astronaut lens,
we have to understand, the ancient man
went to great lengths to depict and explain how this form
of travel was taking place.
And it might be that this is something that
was extraterrestrial in nature.