[narrator] We have uncovered
a remarkable planet...
...a world
of extreme weather...
...alien landscapes....
and bizarre phenomena.
It's the most complex system
we know of in the universe.
That planet...is Earth,
and we're only beginning
to unlock its secrets.
Even with what's already known
about this world,
it continues to surprise
and mystify.
Beneath its surface,
a bizarre underworld
operates by its own rules
with its own climate.
[man] It's extremely hot.
If you were
in there unprotected,
you would have
about ten minutes
before you died.
[narrator] What strange forces
caused towers of rock
to rise from this lake?
What secret creatures
are remaking
these earthly landscapes
into alien worlds?
These are
the strangest places,
and they hold the deepest
secrets of the earth.
Any visitor passing
through the solar system
would notice how strange
Planet Earth appears...
...and a closer look reveals
only more strangeness.
[man] I'm not saying that such
places don't exist elsewhere,
but I think that
they're very, very rare.
Looking at our solar system
and other exoplanets,
we do not yet know of anything
quite like Earth,
and so, in a sense,
Earth is the strangest of all.
[narrator] One of the strangest
sites on Earth
exists in Mexico's
Chihuahuan desert.
1,000 feet
under Naica Mountain,
giant, mysterious
white crystals
crisscross a dark cavern,
creating a real-life version
of Superman's
Fortress of Solitude.
Few humans have experienced
the crystals in person.
NASA planetary scientist
Chris McKay is one who has.
[McKay] The crystals
are really quite amazing,
awe-inspiring.
Walking into this room, you see
absolutely spectacular,
perfectly-shaped crystals
that are this big around
and as long
as a telephone pole,
beautifully formed,
crystal clear.
[narrator] The crystal cave
has its own extreme climate,
where the temperature blisters
at 120 degrees Fahrenheit.
This comes from the heat
emanating up
from a magma chamber
below the cave.
[McKay] It's extremely hot,
very, very high humidity.
In fact, if you were
in there unprotected,
you would have
about ten minutes
before you died.
So, when we go in the cave,
we wear special suits,
carrying ice packs,
to allow us
to stay in the cave
for 30, 40 minutes.
[narrator] How did
these giant crystals
end up here in this
hellish environment?
The first secret is gypsum,
a common mineral that's also
the main ingredient
in drywall.
Gypsum-rich water once filled
this cave completely.
In the presence
of heat and water,
some minerals dissolve,
...but gypsum turns brittle
and crystallizes.
For half a million years,
the gypsum crystals
grew underwater
and undisturbed.
It wasn't until 2000
that a mining operation
probing for precious metals
discovered the chamber.
It pumped out the water
and revealed this
unique treasure.
NASA astrobiologists
like Chris McKay
are studying microorganisms
encased in the crystals.
This alien environment
has given him a chance
to try out techniques
that can be used
to hunt for life
on alien planets.
[McKay] We are
exploring methods
that can do remote sensing,
into the crystal,
to study what's inside them
without damaging the crystal.
The same technologies
that allow us
to explore a rock on Mars
from several meters away
allow us to look
at the microorganisms
that are entombed
in these crystals.
[narrator] An initial survey
revealed that the chamber
held a total of 170 crystals.
Scientists, however, have
a limited time to study them.
Once the mining operations
cease and stop removing water,
the chamber will flood again,
sealing it forever.
Just 500 miles to
the northeast of Naica,
the rolling hills
of Central Texas
cover their own unexpected
explosion of crystals--
...the strange,
alien formations
of the Caverns of Sonora.
[Man] Most caves you go into,
you're in these
bedrock tunnels,
with a stalactite, stalagmite
here and there,
but here the whole thing
is virtually crystal.
[narrator] The spectacular world
of the Caverns
remained a secret,
unknown to humans
until the early 20th century,
when a dog chased a raccoon
into a 20-inch opening
between some rocks.
When the locals
explored the opening,
they discovered a deep pit that
prevented them from traveling
more than 500 feet
from the entrance.
Finally, in 1955, three cavers
managed to cross the pit.
On the other side,
they discovered
seven miles of passages,
almost entirely coated
with crystals.
Although these crystals
are underground,
the secret to their creation
begins with weather
on the surface.
20 inches of rain
fall here every year.
That rainfall seeps
through the ground,
picking up minerals
as it finds its way
into the limestone bedrock
surrounding the Caverns
150 feet below the surface.
[man] The limestone
is like a sponge.
It holds a lot of water.
It doesn't come in real fast
but it drips, you know,
a steady drip most of the time.
[narrator] As water arrives
through the cave ceiling,
it sheds calcite minerals.
A single crystal forms
in the stagnant water,
taking the shape
of a lopsided box.
Instead of dripping
down to form
stalactites or stalagmites,
the crystals stack together
into a variety
of strange configurations.
It isn't just moving water
shaping the caves.
A silent and nearly
invisible force
is at work here, too,
and it has to do
with the cave's weather.
[Veni] Moist air
is coming through the cave.
It runs along the wall
and it's dissolving
this back side,
and down here,
you see that it curves
with the direction of airflow.
Now, you'd think that maybe
there was a hurricane
of air flow
moving down through here,
but this is really just
very, very gentle breeze that
you probably wouldn't even feel
that's happened over thousands
and thousands of years.
[narrator] Water and rock
mix all the time on Earth,
but in one place, the water
is so strange,
it brings something
that looks like
an alien world
up to the surface.
In some secret corners
of Planet Earth,
even the water is strange.
Through the Sierra Morena
mountains
of southwestern Spain,
a bizarre river
runs blood red.
The unusual color
of the Rio Tinto
comes from a high concentration
of dissolved iron
picked up
from the area's rocks.
In southwestern Turkey,
shockingly blue pools of water
sit on a bizarre landscape
of what appear to be
icy terraces...
...but this place
isn't icy at all.
Known as Pammukale--
Turkish for "cotton castle"--
this strange place
is actually made of rock.
17 boiling hot springs spit
jelly-like calcium carbonate,
also known
as limestone or chalk,
out onto the hillside.
The naturally white mineral
then cools and hardens.
The hot springs have been
attracting tourists here
since Roman times.
[man] There's a whole line
of these springs
issuing out in one location,
and the springs have
probably been active
for maybe a couple
of million years,
and there you've
built up terraces
that are literally
hundreds of feet high.
[narrator] On the other side
of the planet,
just to the east of Yosemite
in California,
even stranger water laps
onto the shores of Mono Lake.
It lies 400 miles
from the nearest ocean,
but it's salty.
Adding to the oddity,
the water foams like soap
and grows
gnarled rocky spires.
Making this alien setting
even more unusual
are its
shockingly unpredictable winds.
They can transform
the waters of Mono Lake
from glass-like calm
to dangerous white caps
in just minutes.
August 31, 2008.
An experienced local kayaker
took to the waters
when suddenly, the winds
roared to life.
In minutes, they had spun
up to 80 miles per hour.
The hurricane-force winds
launched so much foam
into the air
that pilots
flying over at 30,000 feet
thought one of the islands
in the lake
was erupting like a volcano.
The local man's
kayak was found
beached on an island
two days later,
and his body was discovered
some 700 feet down the shore.
Writer Mark Twain
nearly suffered the same fate
over 150 years earlier
when a sudden storm
almost capsized his boat
on Mono Lake.
He later wrote
that he was afraid the boat
would be swamped
by 100 gallons of soap suds.
However, the lake
Mark Twain saw
was very different then.
The peculiar columns crowding
the lake's shore weren't there.
[McKay] The reason
that they're exposed now
is because the water supply
to Mono Lake
has been depleted
over the last many decades
to provide water
for urban areas in California.
So, the lake level
has gone down.
So, these structures
have been revealed.
If the lake were
back to its historic level,
we'd be underwater right now.
[narrator] What's the secret
of the rocky towers?
The lake rests over a series
of freshwater springs
that bubble up from below.
That spring water
carries minerals like calcium.
When it comes into contact
with the lake water,
it solidifies into limestone--
the same compound found
in Turkey at Pammukale.
The odd water of Mono Lake
comes from the rain and snow
that falls
on the surrounding mountains,
runs through the rocks,
and ends up in the lake.
[McKay] And so, the water
leaching through those rocks
is bringing a real
interesting mix that reflects
the chemistry of the rocks
that surround the lake.
[narrator]
Besides a heavy dose of salt,
the lake water contains
an unusual amount
of sodium bicarbonate,
or baking soda.
That's what causes
the water to foam.
[man] On a windy day,
the wind whips the carbonates
up off the surface of the lake,
and they pile up onshore,
like this.
[narrator]
Strange places can emerge
where water is nowhere
to be seen.
In a desert, an almost
invisible crack in the land
bears the scars
of an ancient earthly force,
one that returns
again and again.
Earth's desert landscapes
seem to breed strange places.
One of these hides
inside of a long crack
in a rocky hill
on Navajo territory
about 300 miles
north of Phoenix.
This is Antelope Canyon.
[man]
This is an interesting place
because of its shape.
It's incredibly deep
relative to its width
and it has
remarkably sculpted walls.
[narrator] A sliver
of powdery, red sand
flows over the floor.
It runs for over 1,000 feet
between gently curving,
100-foot-tall walls.
Why is it so steep and narrow,
and how are the walls
so impossibly smooth?
As with most canyons,
flowing rivers
are part of the secret.
That's especially true
here in red canyon country,
where the rocky ground
hardly absorbs any water.
The process began
150 million years ago,
when floodwaters carrying sand
found just the slightest
of fractures
at the top of this
ancient sand dune.
Over time, that water
ground through the stone
like a chainsaw.
[House] There is an area
of land upstream
that collects the water
from rainstorms
and concentrates it
in this channel,
and it enters the canyon.
[narrator] On August 12, 1997,
the canyon became a deathtrap.
A rainstorm several miles away
filled the incoming channel
with four feet of water.
It surged into a nearby branch
and transformed
into a 30-foot-deep swell,
drowning 11
unsuspecting tourists.
Two of their bodies
were never found.
The floodwaters
aren't arriving empty-handed.
[House] I'm standing
in the dry streambed
of Antelope Canyon,
and I'm standing next
to a series of terraces,
and it indicates
that the entrance to the canyon
often fills up with very large
volumes of sediment
that end up getting funneled
through the canyon.
[narrator] Most of that
incoming sediment is sand,
but the floodwaters
also pick up sand
from the walls themselves.
Known as Navajo Sandstone,
the red rock of Antelope Canyon
is made up of piles and piles
of sand packed together.
[man] This area at one time
was a giant sand dune
that covered this region
millions of years ago.
Then we had glacier ice
that came in from the north.
Water put pressure on the sand,
compressed it,
and turned it into stone.
I have two pieces
of the Navajo sandstone,
the same rock that
makes up Antelope Canyon.
Just by rubbing
these two rocks together,
I've created
a very smooth surface
on each of the rocks.
This is much like
what is happening
inside the canyon
during a flood.
[narrator] The Navajo name
for the canyon
is "the place where the water
runs through the rocks."
Even today, floods charge
through the canyon
up to eight times a year.
[Etsitty] The water
comes through
spinning and violently turning,
very similar
to a washing machine,
and it carves
out the canyon walls that way,
making it smooth.
[narrator] Sometimes this world
hides its secrets
within the walls
of a nearly hidden canyon.
Other times, it bares it all
right in the open in the most
unexpected of places.
The strangest places on Earth
are often found
in the most desolate corners
of the planet,
but even for this world,
a fountain
gushing non-stop from the floor
of a barren wasteland
is especially bizarre.
Here in Nevada's
Black Rock desert,
that's only
part of the oddity.
This is Fly Geyser.
It's still growing, and fast.
[Faulds] What's a little unusual
here is the amount of material
that has come
out on the surface
and accumulated just in a matter
of several decades.
[narrator] The secret
to why Fly Geyser grows here
in the middle of the desert
has to do
with how that water gets here.
It starts off normally
as rain and snowfall
landing on the surrounding
mountains.
As this water trickles
toward Fly Geyser,
it encounters
a natural furnace
created by movement
in this region's terrain.
[Faulds] The crust here
is being pulled apart.
It's being stretched,
and so, there's lots and lots
of fault lines and fractures.
The snow can melt
and percolate
downward along those
faults and fractures.
[narrator] This steamy water
collects beneath Fly Geyser
in an aquifer, a reservoir
of saturated rocks.
All the water needs to reach
the surface is a crack.
In 1964, hot water
burst to the surface
and started dumping
a heavy dose of minerals,
especially calcium carbonate...
...the same mineral
that makes up
the cave walls of Sonora
and the towers of Mono Lake.
Here, it first accumulates
into rounded towers.
Then, as it trickles
to the ground and settles,
the calcium carbonate hardens
and forms individual pools.
Calcium carbonate
is normally white...
...but a strange form of life
clinging to the Geyser
is covering it up.
[Faulds] There's a couple
different types of algae here.
There's a green algae
and a red algae,
and algae loves
warm, mineral-rich water.
[narrator] This particular algae
thrives in searing heat
where other
earthly life cannot.
As Fly Geyser
continues to gush,
grow, and cultivate life
in the middle
of a dusty basin,
it takes its place
with the other
bizarre mysteries of Earth.
[Filippenko] We see
some of these phenomena
individually on other planets
and moons,
but to get
all the kinds of attributes
that we have here on Earth,
I think is really
quite rare in the universe.
[narrator]
It is only by examining
all the workings
of this world,
common and peculiar,
that we begin to comprehend
how strange this Earth is.