I'm here in the jungle of the Yucatan, which is not the kind of place you normally expect
to find an underwater kind of guy like me. But flowing beneath these forests are incredible
underground rivers, and in places holes in the forest floor like this one provide access
to an amazing unseen world.
Hi, I'm Jonathan Bird and welcome to my world!
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The holes in the ground are called cenotes, from a Mayan word meaning "Sacred Well."
But not all cenotes look like a hole in the ground. Some appear at first to be ponds.
Yet they all share one common trait—they're openings to underwater caves and caverns.
Mexico's Riviera Maya in the Yucatan peninsula is a vast rainforest, filled with hundreds
of cenotes. There are thousands of miles of underground rivers here.
My adventure begins first thing in the morning at H2O Pro Diving in Tulum, where we load
our gear into a van to begin the journey out into the middle of nowhere, towards the cenote.
My guide, Marco Wagner, is an experienced caved diving instructor, who will keep me
out of trouble with a safe introduction to the sport of cenote diving. Unless you're
specially certified for cave diving, you should only dive with a local guide who knows the
cenote well.
Today we are diving a famous cenote called Calavera.
MARCO: (with German accent) Calavera means translated skull. And you see mouth and you see the small
eyes there; there are all these small eyes where we see in the dive where the light beams
are coming in and they look like disco lasers.
JONATHAN: WOW!! This is really way out in jungle. How do you think anybody found this
place?
MARCO: I mean they get explored by the owner of the land. They have these huge pieces,
huge chunks of land and actually they chop the trees down and they make trails and they
find the cenotes. And also cenotes are here for ancient Mayans also which were like sacred
wells for them. That's where the cenotes are coming from. It's coming from Mayan
word Dzonot that means sacred well.
JONATHAN: So for the Mayans...this was an important source of water or...?
MARCO: They also used ground water as well, but also for sacrificing for the gods some
cenotes were used. But still this ground water also still comes from underground rivers that
we have here in the peninsula.
JONATHAN: Wow! That's cool. It's deep too! So we're gonna have to jump down? How
far is that?
MARCO: That is about two meter fifty, three meter, more or less.
JONATHAN: ECHO!! That's going to be fun.
Now it's time to begin our dive. We grab our gear from the van and suit up near the road.
Marco is wearing double tanks and all kinds of cool technical cave diving gear.
Me? I'm just wearing my normal scuba gear and a few extra flashlights.
The
walk in was plenty long and hot enough when I wasn't wearing my dive gear!
That water is going to feel so good!
Marco gives me some last words of advice before the plunge. I think I'm more worried about
the 10 foot drop into the water than the dive itself!
Cliff diving! Woo hoo!
The water is extremely clear. I adjust my camera lights and follow Marco down below
the Earth.
As we enter the cenote's cavern, I realize that I'm truly heading into another world.
This is not my area of expertise. I follow Marco carefully and pay attention.
We have brought some humongous lights to help illuminate the cavern for photography and
they really help show what it looks like. It's beautiful
The tunnels were formed by water rushing through and dissolving the soft limestone, but the
intricate decorations hanging from the ceiling called stalactites can only form in a dry
cave.
Thousands of years ago—during the last ice age—the water levels were lower and these
very caves were bone dry.
That's when these impressive stalactites were formed.
On a visit to a dry cave, I can observe the actual growth of stalactites...but its pretty
slow. It works like this:
When it rains up in the rain forest the water percolates through the limestone and along
the way it dissolves a little bit of the limestone. Then it drips from the roof of the cave and
over thousands years each drip leaves a little bit of limestone behind forming an icicle-like
structure call a stalactite. They get longer and longer and longer with time, but the water
continues to drip and eventually it hits the floor of the cave forming a little bump, and
that bump gets bigger and taller and taller forming sort of like an upside down icicle
called a stalagmite. If you wait long enough the two of them keep getting longer and longer
until they connect into what is called a column.
At the end of the ice age, the sea levels rose and so too did the ground and so too
did the groundwater levels in the Yucatan. Soon these huge subterranean caverns filled
with water, leaving the stalactites frozen in time.
In some places the caverns have huge air pockets where the water doesn't go all the way to
the top. Here we can surface for a breath, and take a look around. Some of the cenotes
can even be explored by snorkelers!
Good buoyancy control in the cavern is essential. The limestone formations are incredibly beautiful
yet fragile sculptures. The formations took thousands of years to form, but a single careless
fin kick could destroy them in seconds. So we must kick gently and stay off the bottom.
The floor of the cenote is covered in super-fine silt. Swimming too close to the bottom would
stir it up and reduce visibility to zero, which could be very dangerous.
As I follow Marco deeper, the water starts to get weird and blurry looking.
Many of these underground rivers make their way to the ocean. At some point along their
journey, the water transitions from fresh to salt water.
Salt water and fresh water have different densities. The interface between the two different
densities can cause an optical condition called a halocline where the water appears blurry.
It's a weird swirly foggy haze.
I follow Marco down below the halocline and into the salt water. I can taste the salt
on my lips, and the temperature is about 5 degrees warmer!
Soon we reach the swiss cheese room. Down here, a chemical reaction with the salt water
eats away some of the limestone, creating thousands of holes in the rock—and the unique
swiss cheese appearance. It's a completely different kind of formation than I saw in
the fresh water part of the cavern.
As we swim into the far reaches of the cenote, we eventually reach a point where we can no
longer see sunlight from the opening. This has now become true cave diving...a much more
dangerous activity.
Here we find a sign warning divers to stop and go no further. People have become lost
and drowned in these vast labyrinths. This is as far as we go.
Turning around, we head back out towards the entrance. Just before we reach the light of
day, we find some Mayan pottery on the bottom—probably thrown in to the cenote as an offering to
the gods. The Mayans believed that the cenotes were pathways to the underworld. Offerings
of gold, food, pottery and even humans were made to the gods through the cenotes.
With my scuba tank getting low, the time has come to leave the cenote. So I head back to
the surface.
In the shallow water just below the jungle, tiny fish come over to check me out. Some
of them nibble on my hair and ears. They must be really hungry they think I look like lunch!
WOW! I can't believe all the cool things I saw in this cenote. Who would have thought
that there is so much amazing stuff hiding under the floor of forest? Even though I'm
done with my diving for the day I think it's time for one more dip!
Woo hoo!
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