All language subtitles for Hidden Worlds 3D Caves of the Dead 2013 720p BluRay DTS x264.ENG

Hidden Worlds 3D -
Caves of the Dead

Yucatan, a peninsula on the land
bridge between North and South America.

The heartland of the
historical Mayan empire.

Ostensibly, an arid coastal region
without rivers or large lakes.

But numerous, mysterious waterholes
in the middle of the jungle

tell a different story: of a
secret, hidden beneath the surface.

Trees and plants stretch their
roots here, in the dark kingdom

of three subterranean
rivers - Yucatan's lifeblood.

They flow through the presumably
largest underwater cave system on earth

extending beneath the peninsula.

Formed for millennia, accessible only
through crevices in the limestone rocks

and shrouded in mystery - the cenotes.

Even larger quantities of
rain rapidly seep through

the porous limestone, creating a
dry and almost inhospitable effect.

Yet the subterranean water resources

ensured and still do provide
lush and varied vegetation.

The Maya often built their
temples close to the cenotes,

as in addition to providing their water supply, they
were considered to be the sacred entrances to Xibalba:

the Underworld - the mysterious
realm of darkness, of fear,

of death - ruled by the gods.

The appeasement of these gods
constituted a special place

in the rites and ceremonies of the Maya.

Long before the first Europeans
set foot on the American continent,

trade, science and social life

flourished in Yucatan.

Divided into city-states, based
on strict, religious rituals,

the Mayan Kings ruled their empires
unrestrictedly and as equals with their gods.

Numerous mysteries revolve

around the history of the
Central American continents

most significant civilisation.

The ballgame of Pok ta Pok is closely
associated with the myth of Xibalba.

It was based on an ancient legend,

in which the battle between the twins
Hunahpuh and Xbalanque is re-enacted.

They descended to Xibalba,

where they were challenged by
the gods to play a ballgame.

According to legend, they
defeated the gods of the underworld

and ascended to heaven
as the sun and the moon.

The game was also seen as a symbol of the cycle
of life, mankind's journey from birth to death.

However, death was very real. The captain
of the victorious team team was sacrificed

to the gods of Xibalba and thus acquired
godlike status. A bloody custom, but also a

great honour apparently,
which was hard fought for.

Now, little more than crumbling stone
buildings testifies to the former power

and progress of the Maya Kingdom.

Here we have Robbie
Schmittner and Florian Huber.

The former is one of the most
experienced cave divers of the region.

Florian is a marine archaeologist
from the University of Kiel in Germany.

Both are united in their
fascination for the ancient relics

that can still be found
in and around the cenotes.

For several years now, Florian
has been commuting to Mexico with

a team of research divers of the Kiel
Institute of Prehistory and Early History.

The Yucatan primeval forest is yet to
reveal all of the secrets of the Mayas.

Treasures, hidden in the dense jungle

and the subterranean rivers and
cave systems of the peninsula.

Robbie Schmittner's
diving centre in Tulum.

The linchpin for exploring
Yucatans underwater world.

This gives us an insight.
What we just saw on the big map

is just a system of around
200. When we take a look

at what we have in this system, we can
see 3 main arms. This one comes down

that one there and this
one comes down here.

That's why this system
was called Os-Bel-Ha,

which means three waterways.
They're partially connected

at the sides, but the
main passages are OK.

At some point, sometimes indirectly, the
water eventually manages to run out to sea.

Florian Huber, Robert
Lehmann, Christian Howe

and Uli Kunz have spent
the past four years

exploring the Yucatan cave system. A
highly-specialised team of professionals

who meticulously plan
every dive they make.

Always, unfortunately. You know, whenever
real characters have to work together,

there's always friction.
Since 1980, most researchers

who've been exploring here
gave their data to QRSS, a base

where all data is stored and they reach a
point where sometimes something gets lost

or someone doesn't pull his weight. It could
be that something's missing here or there,

but most of what's been found
so far can be seen on the maps.

We want to risk it and dare to undertake
the journey into the mystical underworld

of Xibalba, which, in the days of the
Maya, really was a journey of no return.

Today, it is one of the biggest
big challenges a diver can face.

But before the scary stuff starts,
we still have some humping to do.

Before each dive, about a ton
of equipment has to be loaded.

At 30 degrees in the shade, this
is a challenge for any deodorant.

Then we're off, at first,
through rough terrain

in the middle of the Mexican jungle.

En route, we have to make our way
through the dense forest with a machete.

Florians GPS shows us the way.

Flo, what does the GPS
say? Where are we going?

This way I think.
- Here? OK?

I think I see water over there.

Oh wow, look, clear water.

Now, that is a hole.

It's a good sign to see fish here.

In every cenote we find
with a cave beneath it,

we nearly always find fish.

There's an awful lot of
organic material in there

that first has to be chopped out.

Someone has to go in with a
mask and see if there's a tunnel.

It's best Rob goes.

Hey, here is something.

Robbie, I can feel stone here.

If you look, there's a
crevice in the middle.

It's improbable that the
cave ends in the middle.

Look at the side. Over here.

Oh man, where is he?

He's OK.

Fantastic.

It's a really great cave.

It drops down a lot here at the front,
but there's a really small fissure.

You have roughly four metres,
then you have to submerge.

Once you get through
there's a small fissure.

We can get through sidemount,
so you can forget backmount,

we need complete sidemount equipment.

You'll probably have to take
the bottles through up front,

it's really narrow. But then the cave
just opens up really big, it's beautiful.

So we're off, we've
discovered a cave opening.

But first we have to hump
all of the equipment over here

and set up a safe base
for our first cave dive.

While the team is getting ready,

Robbie looks for the best
place to attach the guide rope.

We need that to find
our way back out again.

Oh no, it stinks here SO bad.

That's us.

Yes, when you come out again maybe.

That'll be quite something.
Robbie, take a deep breath.

Nice.

Man, it stinks to high heaven here.

Ok, let's go! You follow us.

We descend through a dense forest
of reeds and underwater plants.

Some of the plants almost seem to
breathe in the light of our lamps:

A surreal sight, which complements
our descent into the underworld.

We find the passage one after
another and carefully dive through.

Now, we are entering Xibalba,
the caves of the dead.

The safety rope will
guide us back again.

I hope. it's vital
to secure it properly,

as it's easy to get lost
in this labyrinth of caves.

That could end badly,

as down here it's impossible
to surface quickly for air.

The cave narrows, we
carefully continue our dive...

The first obstacle: A very tight
section that we can only get through

with the scuba tank stretched out in front
of us, a so-called twister restriction.

Time to take off the equipment
and pull our stomachs in.

The name twister restriction
comes from the style you need

to adopt to pass through. The only
chance you have of coping with bottlenecks

like this is to turn, little
by little, like a screwdriver.

At the same time, you have
to fight against the current.

On top of this, the dispersed
sediment hardly helps matters:

within the shortest space of
time, vision is down to zero.

This is definitely not for the faint of
heart. Just what have I got myself into?

Ah well, made it! I ask
myself if I'm the only one

feeling a little queasy
in this pitch darkness.

Well, not Robbie anyway. He calmly
secures a marker to the rope.

It's a sign cave divers use, so that
everyone knows: here is a turn-off.

The direction a marker
points to can also be felt,

which means that you can find your way
back even in total darkness. They say.

Little by little, we pull our guide
rope behind us through the cave

and continually fasten
it to specific sections -

as according to the Greek
legend, Perseus once did,

using a ball of wool to find his
way in the Minotaur's labyrinth.

We need a similar form of
reliable guidance, as without it,

even the pros can lose their way down here.
I knew I should have taken up knitting.

We're now diving through our first hall.
During the course of millions of years,

a forest of stalactites and
stalagmites has formed here.

In the light of our diving lamps,

the petrified water droplets
have a ghostly appearance.

Then, out of the blue, our first find!

Florian has noticed a dark
irregularity on the floor of the cave.

This must be the prehistoric
fireplace we were told of.

A C14 analysis revealed

that a fire had burned
here 8400 years ago.

The caves were not completely
flooded at that time

and were inhabited by
both humans and animals.

The fireplace has been
perfectly preserved

due to the slowly rising sea
levels. An intriguing notion,

to think that here, where we are
diving, Stone Age people once lived:

And that this piece of
charcoal is a relic from a time,

many thousands of years in our past.

We dive further. Our path continuously
leads us through new stalactite formations

They hang from the ceilings
of the caves like spearheads.

Inspiring fear, yet also
fascination - in that order.

Then we make our next find! We discover
a ceramic vessel on a small hill.

The shape and the workmanship suggest
that it is from the Maya period.

The sediment and woodchips
surrounding the find site

lead us to believe that it probably
fell through a long-since buried cenote.

Christian films the
vessel from all sides

to be able to examine it later.

Immediately next to it,
Florian measures another vessel.

He records the data in his wet
notes, a special notice block

made of water-resistant paper.

The vessels could have fallen
down here whilst collecting water.

This could be in individual cases,
but therefor they are found to often.

It is assumed that they are
Mayan offerings. Incense, flowers

and even food were offered to the
gods in receptacles like these.

But rites also took place
in which the cut out hearts

of those sacrificed were offered

to the gods of Xibalba in clay pots.

Just which version and with
which frequency this happened,

is almost impossible to ascertain.

What we find on a nearby
ledge is not the first small,

dead Maya of our expedition, but
unfortunately, just the skull of a monkey.

But time is of the essence. The
discovery bug or not - we have to go back.

The oxygen reserves in our
bottles limit our stay down here.

We are aware of the fact
that we are simply guests

in this fascinating underwater world.

It is easy to lose track of time in
this spellbinding and alien environment,

which makes the confrontation
with the inevitable harsher still.

It's not advisable to surface when in
narrow places and with miscalculated

time limits. I can almost make out
the lid of my coffin in front of me.

Taking no risks,

we begin our return journey
with Christian in the lead.

Our guideline leads us safely
back, out of the labyrinth.

Back into daylight. Back from Xibalba,
the underworld, the place of no return.

Tree roots that have grown through
the limestone and now hang in the water

assure us that we are nearing the
surface. We have almost made it

and just have to fight our way
through a thicket of aquatic flora.

Of course, this was a completely different
cave to those we have dived in before.

It's a mixture of both light and
dark. The stones are bright enough,

but there's a lot of silt,
detritus - all dead plant material -

distributed throughout the entire cave.

In all of the rooms.

And there, on a small pedestal
there is this broken pot,

that's really great. it looks fantastic.

We're now on our way to (Denote Zapote,

a so-called sinkhole.

This means, there is only one way
- down. There are no turn-offs.

The usual procedure -
unloading bottles and equipment.

But before anything else, Robert
has to ask the gods for permission.

I'm told the backflip
is his annual ritual.

We call this cenote Hells Bells and the
name didn't come about quite by chance.

In the course of the millennia, huge
bell-shaped stalactites have evolved here.

That makes this dive
site really special.

They're really big, some
of them measure two metres.

Hanging from a single point on the roof,

they look just like bells.
They are absolutely impressive.

In fact, we have never seen
anything quite like this before.

Without doubt, this is one of the most
beautiful dive sites I have ever been to.

And I'm really looking forward
to diving back down there again.

So let's get down to Hells Bells.

We're going down. Soon, our lamps
will be the only light source

in the unreal darkness of the cenote.

At approximately 30 metres, we
encounter a so-called halocline:

a mixed layer of fresh groundwater and
salt water, a vertical salinity gradient,

which is flushed into the caves
owing to the proximity of the sea.

The fresh, or low salinity
water swims above the salt water

due to the differing weight
specifications of the two types of water.

The result is a mixed layer in
which vision is slightly impaired.

It's not easy to find your way in this.

But underneath this, visibility
is back to normal again

and we continue our descent.
We dive through a crevice

...and there they are: Hells Bells.

An unreal world reveals
itself, albeit partially fuzzy,

embedded in the watery
foothills of the halocline.

Hundreds of bells - some
two metres in diameter,

others seemingly tiny in comparison.

The very sight of them
is truly arresting.

The light from our lamps
refracts green. A sure sign,

that the composition of the
water down here is different

to that of the upper regions.

The colour of the light refraction and
the concentration of airborne particles

suggest a high sulphur content. This is
logical, as the bacterial decomposition

of organic material passing down
releases sulphur when it decays.

There are several theories regarding
the origin of these bell-shaped oddities.

The most popular of these assumes
that due to specific bacteria

on the surface of the subterranean
lake, lime was precipitated.

The sinking water level caused
these rather special stalactites

to increase in size, larger and larger.
There was no water in the cave at this time,

enabling the bells to develop
as a special form of stalactite.

This phenomenon is also
referred to as a “showerhead”,

being as it is reminiscent of a
domestic showerhead distributing water.

And all of a sudden, faced with this
unreal world, it no longer seems so absurd,

that this place should be the
entrance to the underworld.

In Xibalba, after his death, a man
had to go through many tests and trials

before he could enter paradise.

Just as we have to endure
the rigors of cave diving

to be able to explore this fascinating,
mysterious world. I must admit,

it's quite scary - on the one hand,
swimming around at the very gates

of hell itself, and on the other, the
very real dangers down here in the deep.

And now it really is time for us
to begin with the return journey.

At depths of 40 metres, the
pressure on our bodies is immense.

This has to be regularly
monitored during our recent,

to reduce the risk

of any of us getting the bends,

the dreaded diver sickness.

Whatever happens, as far as we're
concerned, Hells Bells is the belltower

of Xibalba, a place that brings the
mysticism of the ancient Maya back to life.

We write the year 900 AD. The
king seeks advice from the gods,

as a drought plagues his country.

His people still have faith in him, but
his supposedly divine power is beginning

to crumble in step
with the rise in famine.

Thus, he has war fought against his neigh-
bours and the bloody harvest was abundant.

Prisoners are dragged into the jungle.

The King dances with the Gods. He is
their descendant. He will appease them.

The chosen must see the
honour bestowed upon them.

As sacrifices, they will
immediately enter paradise

and will not have to endure
the suffering in Xibalba.

But either way, they have
no choice in the matter...

And so, the legation of the priest
reaches the sacred caves, here,

the power of the gods is exceptionally
strong. It is yours, to beg for admittance,

should you not want to
incur their wrath upon you.

The king awaits them. It is his
duty to appease the gods with blood.

For his people, for his power.

Back to the present. We have
permission to dive in Las Calaveras,

the Cave of the dead Maya.

For this dive Florian and his team

have ordered a special gas mixture.

We use a substance known as nitrox,
which is oxygen-enriched air.

It allows us to work
underwater for longer.

The nitrogen is always the main
problem when diving. it can saturate

and at some point in time, it
forces us to come back outside again.

When we reduce the nitrogen
levels and increase the oxygen,

we can't dive so deep,

but in the cenote we
only have 12 metres anyway

and therefore more
effectivity underwater.

First of all, we have 13 metres
of abseiling to do in the cenote.

By means of a pulley, our Mayan aides
have to manoeuvre each piece of equipment

individually and then
place it into the water.

Exhausting work, at 38 degrees in the shade
and with humidity levels of around 90%.

It's all downhill from here - in the most
positive sense. Sunlight shines through

the rock crevice, causing
light fingers or rays of light.

Dramaturgically, a fitting
start to our descent

into the caves of the dead Maya.

The name Calaveras actually comes from
the finds that have been made herec

as Calaveras is Spanish and means skull,
or deaths head skull, to be precise.

Two years ago, Mexican researchers
discovered 126 skeletons

from the Maya period, on the floor
of the cenote. We are not quite sure

whether it is a Maya cemetery, or a
cenote, reserved for human sacrifices.

In both cases, it remains
a sacred place for the Maya.

Florian is busy
measuring a human hipbone.

To touch or take something with you
from here is strictly prohibited.

He jots down the data
gathered in his wet notes.

Beneath the mantle of darkness, the
first skull is pried from the ground.

The filed teeth are proof,

that this is definitely a Mayan skull,
roughly 1800 years old and well preserved.

Polished, sharp teeth, sometimes
even decorated with jade,

were very popular amongst the
contemporary fashion conscious.

A little further to the left
is a pile of human bones.

These bones form the basis of a theory

that they were used in
human sacrificial ceremonies.

Apart from a few fragments of pottery, there
are no offerings to be found in the cenote.

Some of the skulls do reveal injuries.

Research into this however,
is a task for the future.

Meanwhile, Uli is taking pictures of the
skeletons. In a close cooperation with INAH,

Mexico's official
archaeological authority,

the team constructed special 3D MODELS
in 2010. The object was to examine

the finds in more detail, independent of
diving times and the raptures of the deep.

The area, or field, is
divided into grid squares.

Each find is precisely
documented and registered.

There are many mysteries
waiting to be solved down here

but our journey continues;
and with it, our fascination.

What I see is simply the
incredible potential here.

I think we're just about
scratching the surface.

There's so much here to discover,
there are thousands of cenotes.

There are hundreds of kilometres of
cave systems. Actually, almost everywhere

you jump in somewhere, in every cenote,

there are always artefacts
from the Maya period.

And deep in the caves is where you
can make so many prehistoric finds

animal and human skeletons.

Actually, down here, it's a paradise
for underwater archaeologists.

The largest cenotes in Yucatan are
lake-like incursions in the barren limestone.

Their dimensions can
easily be those of a lagoon.

But why did the Maja
transfigure the watering places?

Well, if one recalls that,
apart from the sea in Yucatan,

there are no rivers flowing
anywhere on the surface,

it seems quite logical.

Access to water is only
possible via caves and cenotes.

This is why the Maya declared
water to be divinely transfigured.

An approach, similar to many
indigenous peoples in Africa.

Guards watch over the water here too.

He who has direct access,
after all, has divine power.

Many cenotes in the Yucatan are
fed by the Ox Bel Ha cave system.

In the language of the Maya, Ox
Bel Ha means “three paths of water”.

This system transports fresh
water inland below the jungle,

through the mangrove forests
on the coast, to the sea.

The Mayas knew the ways of the
water exactly and for this reason,

were able to found their
culture on subterranean water.

That's why the largest Mayan temples are
to be found in the proximity of cenotes.

These secured the welfare of
those who settled close by.

Back to our expedition. The
briefing prior to our next dive.

We dive here right after the entrance
on the left line at the first T,

then down the corridor, keeping
left - that's the route

we already know. We take
the jump to the right,

we saw how that worked last
time. This is the big arrow

and then we dive into the
saltwater. it's around 15

to 20 metres deep and we run into
the halocline, the layer between

fresh and saltwater. Then
we reach this huge tunnel,

there. Here, this big tunnel,

with the main rope.

It means we have to get stuck in again,

and lay a jump on the guideline here.

And when we're here, we'll
start prospecting this area here

and then this one here. And one
of us remains by the guideline

so that he can see at at
all times... and the others,

one takes care of the
left, the other the right.

Then we'll see whether we can find

the assumed prehistotic bones.

Something very prehistoric is
suspected within this cave system.

Florian can hardly wait
to get started and in fact,

our combined curiosity has been sparked.

The first surprise awaits us
shortly after jumping into the water.

A cave of breathtaking
beauty reveals itself,

as if it were a gigantic
underground train tunnel.

But one should never forget the safety pre-
cautions. Robert demonstrates what can

happen when you thoughtlessly flap
your fins. Down here, the sediment

practicly just rests lightly
on the seabed. One wrong move

and visibility is zero.

We dive through a fissure. Not the very best
for those of a claustrophobic disposition.

The crack is just wide enough for us to swim
through without our bottles getting caught.

Our breath accumulates directly beneath
the ceiling and looks like liquid mercury,

hovering immediately above our heads.
Like a scene from a science Fiction movie

set in which the silver surfaces constitute
the transition into another world.

I look around, I must admit
that it looks as though we've

already arrived in this “other world”.

Should the safety rope ever
tear, the silvery bubbles beneath

the ceiling serve as a
signpost toward the exit.

We've heard quite a few
stories whereby cave divers

who had lost their safety's still
managed to save their own skin

by using this trick and following
the bubbles right back to the exit.

We penetrate even deeper into
the cave. Past stalagmites

that look like piles of sand.

Fragile details and bizarre
shapes directly adjacent to them

give the impression of a recent
landslide - only one forged in stone.

Uli christened this stalactite
“The sword of the Underworld”.

I must admit, seen in the light of his lamp,
the scene has something oppressive about it.

We continue our dive. Yet
another cave ahead of us.

A forest of columns is an impressive
image. Fragile and staggered in depth,

one column next to the other: Each of
them different, each of them unique.

By the way, more than anything else,
it is the stalactites and stalagmites

that are proof that these caves
were not always underwater.

The limestone does originate from a time

when Yucatan was beneath sea
level, but during the last ice age,

the sea level was around 100
metres lower than it is today.

Causing the massive
limestone plateau to dry out.

Rain penetrated into the porous stone,
dissolving minerals, and as it dripped from

the ceiling, stalactites were formed:
and those that began to grow toward them

from the ground over the millennia are known
as stalagmites. It wasn't until the sea level

gradually began to rise again,
at the end of the last ice age,

little by little, the caves
were once again flooded.

We've been on the move for
quite some time now. I wonder

where this tunnel leads? I
feel a bit panicky, actually.

We've come quite a way
within a branched cave system

and there is no other exit
other than the way back.

What are we going to do? Keep calm
and all that. I know, don't waste air.

I manage to calm myself down.

Suddenly, the cave opens and we
appear in the middle of the jungle

in a different cenote.

Thanks, Uli. You knew
that it would work.

Fantastic, absolutely fantastic.

Not bad.

Just how huge is this tunnel actually?

Huge corridors, fantastic formations.
The colours of the cave, the thermocline,

the halocline. So indescribable.

The tunnel is similar to a train tunnel.
You just look to the left and to the right

and wait until the metro drives by.

And the entrance is relatively tricky
too. You have to dive here first.

You won't be able to see anything
again as it's full of sediment and crap.

You can feel your way forward bit by
bit using the lead lead and at some point

you'll fall in this cave here and
everything will be crystal clear again.

And then you have this
cave system to deal with.

Very funky, the whole thing.

After a short break,
it's time to move on.

We haven't found anything
vaguely prehistoric as yet,

but we have another junction,
another fork to explore.

Perhaps we'll find something
there. We change the tanks

and make ourselves
ready for a further dive.

We're not about to give up quite yet.

And once again, it's back
down to the flooded underworld

in search of relics of the past.

Slowly but surely, we're getting used
to the bizarre formations and stalactites

down here, almost ignoring them as we
swim by as if they were nothing special.

We are more interested in prehistoric
skeletons, remains of animals from

the Stone Age. My patience is dwindling.

We leave some of our bottles behind

behind and fasten them to the
guideline. The side tunnel is narrow

and the additional tank at our
side - the so-called Stage -

is only intended for
the return trip anyway.

We discover the side tunnel

and now regulate our further procedure
with previously defined gestures.

Sign language is the only language
that works properly down here.

We're laying a jump from the guiderope,

a fork into the still unknown side
tunnel. Then we continue to dive,

always with the rope in our sights,

which of course is absolutely vital,
especially here in uncertain terrain.

Our movements cause ancient
sediment to crumble from the ceiling,

which is a sure sign that this area
has seen little exploration up to now.

Then, at long last, Florian discovers
the skeleton from which we had heard.

Well, that's the way
to get the pulse rising.

Uli takes some shots to keep
everything nice and neatly documented.

It seems to be a megatherium, a
kind of prehistoric giant sloth.

Around 10.000 years
old and well-preserved.

Giant sloths could be anything
up to five metres in length

and weighing several tons. This
animal appears to have lived here,

as in the caves it could not
only find refuge but also water.

The skeleton looks eerie in the flickering
light of the halocline ahead of us.

We dive on to the next cave.

Who knows, we may find something
else on a day like today.

Looking up, I can't help but be fascinated
by the sight of our own spent breath,

which is gathering above me on the
ceiling. For a moment, it looks as

though the air is gushing out of the rock.
But in fact, the opposite is the case.

After a few hours, the air will have
found its way to the top through the rock.

The rock structures in this
cave have something primordial

about them. This is reminiscent
of the nave of a church.

Gigantic stalagmites rise up
from the middle of the room.

Wait, there is something
there, behind the rock.

At first, it can hardly be
distinguished from its surroundings,

until Robert notices the white spots.

With his lamp, he indicates
for us to come closer.

Then, the closer he gets,
the clearer it becomes.

The lower jaw of a huge animal

of apparently prehistoric
origin. Right in front of us.

It once belonged to a mastodon,
an elephant-like animal

that lived here many
thousands of years ago.

Biologist Robert is
clearly over the moon.

A spontaneous lecture
in sign language follows.

These teeth were perfect with
which to crush branches and leaves.

Strictly speaking, these here are two
parts of the lower jaw, very well preserved.

Mastodons were smaller, yet stockier
than their relatives, the mammoths.

We can hardly believe our luck - two
huge finds from the Stone Age in one day!

But now, we really have to get back.
The air supply is slowly running out.

The jump will take us
safely back to the guideline.

Then we take up our stages again. The
additional tanks we left behind earlier

on will supply us with
enough air for surfacing.

Here, Flo demonstrates how
he changes from his back gear

to the stage at his side.

Everyones ready to go. So, let's do it.

We dive through the halocline at
a different location, experiencing

yet another especially bizarre moment:

dead branches, as if
they were gnarled fingers,

show us the way up to another exit.

Robert is still excited as
he relives the last dive.

We found part of a mastodon mandible.

There were actually two completely
preserved teeth in the lowerjaw.

One tooth was really
20 centimetres long,

weighing at least one and a half
kilograms, but it was unfortunately broken.

The second tooth was
15 centimetres longer.

Just ONE tooth, that is brilliant.
As we made this discovery,

it was very special,

it was really very special.
And you could see grooves

on the back molars,

which means that this
animal was somewhat older.

Really, the teeth were totally ground
away. This happens to us as well.

We are constantly grating
and grinding out teeth away!

But I'm sure that the
rest of the mastodon

is somewhere inside there.
It's a very muddy Cenote

Cenote and we just about managed
to discover this mastodon jaw.

But I'm sure that the rest
is down there somewhere.

We just have to go
back in and look for it.

The next day. We prepare for the last

and most extreme part of our expedition.

We learned the cenotes
are connected to the sea.

But can you dive through the caves
and into the sea? We want to find out.

According to the map, there are
several kilometres to overcome,

which is virtually
impossible without scooters.

But before we do anything else, we have to
get some Trimix, a special gas mixture for

deep Sea diving. For safety reasons,
every bottle is carefully examined.

Trimix consists of helium,
oxygen and nitrogen.

We now analyse the
gas, that is, we check

how much bar we have in the bottle and

exactly what gas mixture is inside.

This is quite simply important

important because gases in
certain depths react toxically.

We would have a problem if we have
too much oxygen in the bottle and find

ourselves at a certain depth. This could
turn into a potentially dangerous situation.

This is why everything
is exactly analysed,

then labelled with date and name,

so that everyone knows which gas he has

to whom it was assigned
and we can therefore

exclude mistakes when diving. it's
very important to do this in advance.

Should there ever be an
accident, errors can be traced

more efficiently this way.
Whether this is during analysis,

or whether something went wrong
during the further course of a dive,

or it's just documented,
which gas mixture

is being breathed in the depths.

The checks have all gone well. Now we just
have to load the new bottles onto the pickup

and we can get going.

Our start cenote is situated in the middle
of the jungle. We have determined our exact

position by GPS and estimate

that we should be able to find
a way into the sea from here.

First of all we have some equipment humping
to do, all the way to our mission base.

We're glad everything's ready and ship-shape
and can jump into the water at last.

We have several hours of
being underwater ahead of us.

On to the final adventure, our dive from
the heart of the jungle into the sea!

To cope with such a long distance,
we need underwater scooters,

torpedo-shaped mobility units,

with which we can
almost treble our speed.

And let's not forget, how
much fun these things are.

We glide through the water like fish.

Formations pass us by
as if in time-lapse.

We dive through one cave to the next
with ease, ever deeper into the system.

These Scooters are like a Formula
One ride through the underworld.

We shoot through the Kingdom of
Xibalba en route to the coast,

much faster than without the technology.

And otherwise, the gas reserves in
our bottles would never be enough.

We find an initial breakthrough.
Hanging mangrove roots

as they occur in coastal areas show
us that we are on the right track.

Algae stretch toward us
as we pass through the gap.

Have we already reached our destination?

We surface and find ourselves in
the mangroves of the riparian strip.

At the moment, we are only separated from
the sea by a very thin barrier. So, we head

down again and look
for another passageway.

It takes a while, but
then we find another gap,

through which we can see
light from the other side.

We dive in.

Our first contact with the sea is
blurred. Right in the middle of the tunnel

as if it were a wall, is a halocline. For
one brief moment, we have zero visibility

but don't lose our orientation.

Then we're through. Pure adrenaline.

It worked. That was
fabulous, a great dive.

Toward the end through
the mangrove woods,

then through the beach
section. It got dark then again

and here, up front is a tiny
gap. You can see light through it,

although it was relatively
milky due to the halocline.

And then, all of a sudden, plop - and
then you're through, you've made it.

Our last dive has closed
the gap between the enigmatic

Maya world and the sea.

The Yucatan cave system empties itself into
the sea by means of a continuous current.

We could experience this first-hand.
The basis for fresh drinking water.

The Maya recognised this and
built their religious sites

in the vicinity of the cenotes.

This was in fact the key to the
emergence of their civilisation.

One thesis for their demise
is a prolonged drought,

which destroyed their social structures.

The climate catastrophe could
not be averted, even by increasing

human sacrifices. Wars and secession
shook the very foundations of the kingdom,

causing the power structues
of the Maya to collapse.

We have explored the once sacred
places of this advanced civilisation.

We've experienced the adventure
of cave diving and overcome

the biggest challenge a diver can face.

In doing so, we were able
to admire the amazing beauty

and uniqueness of the cenotes.

Xibalba put us through our
paces, and gave us a hard time.

But in the end, we DID return
from the realm of shadows,

the depths of the underworld
and the caves of the dead.