[music playing]
NARRATOR: Quang Binh Province, Vietnam, 1991--
Logger Ho Khanh discovers a mysterious entrance
to a hidden mountain cave obscured
by dense jungle overgrowth.
The cliffs leading down to the entrance are
so steep he cannot explore it further,
but he notes its location.
Nearly two decades later, the British
Cave Research Association finally explores the cave.
What the team discovers is astounding.
It is the largest underground chamber on the planet.
It's not just a cave.
It's an actual world in Vietnam.
Inside this cave, it's 40 stories high.
There's actually an ancient forest.
It's got flowing water, not just a puddle or a stream
but an actual river.
Inside the cave is an entire growing ecosystem,
and it's so deep that it looks like it's an entrance
to a whole other reality.
NARRATOR: This incredible subterranean realm,
called the Son Doong cave, is estimated to be
roughly 3 million years old.
It runs through the Earth for nearly 6 miles,
and in numerous areas where the cave ceiling has collapsed
allows sunlight to enter, resulting in the growth
of trees and other vegetation.
But according to area residents, what's most notable about Son
Doong Cave are the strange creatures that are
believed to dwell within it.
WILLIAM HENRY: Local residents describe
seeing reptilian-type humanoid beings emerging from the Son
Doong cave, and they believe that they actually
live deep inside this cave.
What's fascinating about this is that these reptilian-type
humanoid beings are similar to the seraphim,
or the winged serpents in Kabbalistic tradition.
The seraphim are said to have gone
and lived in the inner Earth, according
to Kabbalistic teaching.
NARRATOR: Is it possible that reports
of reptilians at Son Doong cave are encounters
with beings from inner Earth?
While it may sound too incredible to be true,
there have been reports that during the Vietnam War
in the 1970s.
US soldiers encountered what they
described as upright lizards inhabiting caves.
And accounts of reptilian beings existing in underground caverns
can be found all across the globe--
even on the other side of the world in Cusco, Peru.
DAVID CHILDRESS: Throughout Peru and around Cusco particularly,
there are many, many stories of a tunnel system
that has something to do with serpent deities, which
they call the Amaru there.
The Peruvian authorities themselves
decided it was too dangerous for people
to go into these tunnels, so they
looked for all of the entrances they could around Cusco,
and they sealed them up.
And this is a well-known story within Peruvian history.
NARRATOR: While there have been many reports
from around the world of human-like reptilians,
there is another inner Earth entity described in the Zohar
that is even more commonly witnessed in modern times.
BEN-TZION SALOFF: According to Zoharic literature,
there are beings inside the Earth having large black eyes
and a nose that leaves only two dark holes on the face.
Now, that corresponds to things that we've seen about,
heard about these, for lack of a better word, ETs.
There is a lot of evidence that these beings that we think
are coming from another planet are
not coming from another planet.
They're coming from inside our own Earth.
NARRATOR: The black-eyed entities, commonly referred
to as Greys by ufologists, are the beings most often reported
by alleged alien abductees, many of whom
claim to have been taken aboard saucer-shaped craft.
Could it be that the so-called flying saucers, so often
reported in modern times, are not coming from outer space
but inner Earth?
According to some ancient astronaut theorists,
this notion is supported by numerous accounts of UFOs that
are seen disappearing into the landscape
and sometimes even flying directly into mountains.