All language subtitles for the.unxplained.s02e03.web.h264-trump-en

Abandoned cities,

ancient cultures
nearly erased by time,

and colossal empires
that simply vanished

without a trace.

How does a civilization
become lost?

Is it decimated by wars,

or does it die off as the result

of some deadly plague
or cataclysm?

What could cause a once‐thriving
group of people‐‐

like the Mayans, for example‐‐

to just abandon
their great cities,

never to return?

Well, that is what we'll try
and find out.

Explorers John Lloyd Stephens

and Frederick Catherwood mount
an expedition to investigate

reports of mysterious ruins

located in this remote,
largely uncharted region.

After scouting and mapping miles
of dark, impenetrable jungle,

they find some unusual features
in the dense brush.

Oddly‐shaped stones,

peculiar carvings

and strange artifacts
that could only be manmade.

It isn't long

before they realize they've made
an incredible discovery:

The remains of the mysterious
ancient Maya civilization,

deep in the rainforest.

And what was so remarkable

to Stephens and Catherwood is,
eventually,

they found temples and platforms
and pyramids.

There was monumental
architecture and conical mounds

and other building platforms
in the rainforest.

And to look at these cities
in the jungle,

kind of coming out
of the jungle was...

was just absolutely remarkable,
and it got people's attention.

On their
return to the United States,

Stephens and Catherwood publish
an illustrated book

of their findings,

detailing 44 individual ruins.

Readers are astounded by the
book's meticulous illustrations,

which portray
a sophisticated ancient society.

And news of the astonishing find

quickly spreads
around the world.

The Maya become more mysterious

as we collect more information.

They have
a sophisticated writing system.

They obviously have a
sophisticated religious system,

a calendar system.

And so, the calendar which would
have been a very useful tool

for the Maya elite and priests
to be able to understand,

say, for example, when there was
gonna be a solar eclipse.

They were ancient astronomers
and architects.

They have social structure

that we're just beginning
to understand,

and their cities are remarkable.

At its peak,

the Maya civilization stretched
from Guatemala and Belize

to western Honduras
and El Salvador.

Their total population was
estimated to be in the millions,

and concentrated
in large city centers

like Copán, Tikal and Calakmul.

And then, suddenly,
during the ninth century A. D.,

this advanced society
just collapsed.

Vast cities, ornate palaces,
towering pyramids‐‐

all of it completely abandoned,

left to be reclaimed
by the jungle.

But why?

The mystery

of why Maya civilization
collapsed is one

that archeology has been
debating forever.

830 is right about when all
of the cities in the Maya area

and all over Mesoamerica
are falling apart.

They drop their tools,
and they walk away.

They're abandoning those cities,
and it's a mystery.

Where did the people go?
Why did they leave?

If you have such
a sophisticated civilization,

how do these things collapse?

What went wrong?

For decades,

archaeologists have speculated

as to what might have caused
the sudden demise of the Maya.

Dozens of theories‐‐
blaming everything

from drought, to disease,

to devastating earthquakes‐‐
have been proposed.

Yet, the simple truth is no one
knows what really happened.

But a recent study‐‐

using state‐of‐the‐art
technology‐‐

might have provided
a significant clue.

An airplane operated
by the University of Houston's.

National Center
for Airborne Laser Mapping

flies 2,000 feet
above the thick jungle canopy.

As the plane reaches
its target area,

an advanced scanning technology
called "lidar" is used

to fire laser pulses through
the trees at the ground below.

When the resulting data
is later compiled

into a three‐dimensional
rendering of the area,

the scientists are stunned
by what they see.

Once lidar got involved,

we saw roads leading
out into other city centers.

We saw thousands
upon thousands of houses.

Collectively, all the areas
that they covered

were over 60,000 new buildings
that we didn't see before.

Previously, they thought

that the Maya reached probably
a maximum level

of population
of around five million.

But the estimates now take us up

to at least 15 to 20 million.

Ever since the rediscovery

of Maya ruins by Europeans
in the 19th century,

nearly every piece of data
uncovered about the Maya

raised more and more questions.

But now, after scientists
began using lidar,

they finally started
to find answers,

such as the possible cause

of the Maya civilization's
collapse: War.

Once we started going out

and recording
and mapping these sites,

we see defense
warfare structures.

This is a remarkable thing
that we never knew

that these defensive works
were out there,

leading archeologists
to scratch their heads

and basically say, "Oh, my gosh."

The Maya were warlike,
and warfare was very important."

We know there was

warfare going on.

They were building all kinds
of defensive structures.

Could that have something to do

with the vanishing
of the Mayans?

More and more,

as the classic period went on,

monuments became full
of war imagery

and people taking captives
and people being beheaded.

So we know war was a factor.

If it was just war, the victors
would have claimed the land,

and the losers
would have beat it.

But that's not the fact.

Everybody left.

Why?

According to the Popol Vuh,

the written history of the Maya,

they believed that time
was cyclical in nature.

Each cycle lasted
for a fixed number of years,

at which time, a great cataclysm
would wipe the slate clean

so a new world could be born
from the old one's ashes.

So was this the real reason?

Did the Maya abandon their great
cities and disband their culture

simply because
an ancient prophecy

told them when exactly to do it?

BARNHART
The timing is very interesting.

In 830, a great cycle is ending.

There was certainly evidence
for them

to believe
that things were going bad.

There were climate problems.

There were resource problems.

There were people fighting.

Were they timing
the leaving of their cities

to the calendar
that they created?

That's a... a big possibility.

Right or wrong,
the Maya believed

that the end of
their civilization was at hand.

And while that may seem like
a farfetched notion,

there actually exists
one group of people

that hold similar beliefs:

The descendants of the Maya.

When you talk
to modern Maya people

in the Guatemalan Highlands,

people called day keepers,
Ajq'ij‐‐

they are priests
who still follow the calendar,

and they teach people
that things begin

and they come to an end,

and that to be in harmony
with the world, you need

to know these cycles and change
before the world changes you.

It's very possible
that back then,

when all the signs that
the world was going a serious

wrong direction,
that the Maya civilization

as a whole said,
"These are the signs.

"The time is now.

Let's collectively
change ourselves."

Was the collapse

of the Maya civilization

simply the result
of a self‐fulfilling prophecy?

There are many
who aren't so sure.

As far as they're concerned,

something more
sinister happened.

And they believe
the evidence can be found

by studying the fate of another
ancient civilization,

one found much closer to home:

The Anasazi.

Set into the high cliffs

of Mesa Verde National Park
in southwestern Colorado

is what many consider to be
America's biggest mystery.

A mystery carved in solid rock.

Cliff Palace,
as it has come to be known,

contains more than 150 chambers

connected by extensive ramps
and stairways.

According to most archaeologists
and historians,

it was constructed
almost a thousand years ago

by a tribe
of Ancestral Puebloans

known as the Anasazi.

The Ancestral Pueblo
are a people

that grew up in the Four Corners
area of the United States.

They're actually in an area
called the San Juan Basin,

where they spent most
of their culture's history,

all the way
into Paleo‐Indian times,

which is about 12,000 years ago.

They're a culture
we call Basket Maker,

and they did most
of their cooking and gathering

in pit houses
and weaved baskets.

I think one of the things
that's the most admirable

about the Ancestral Pueblo
is their ability to live

in such
a resource‐poor environment.

It was highland desert.

There were not
many natural plants to eat.

It was very difficult
to grow corn.

There were not a whole lot
of animals to hunt,

and yet they found a way
to live in that niche

and survive.

Starting in the ninth century,

the Anasazi expanded
their civilization

by building massive structures
throughout the Southwest,

first in New Mexico's
Chaco Canyon

and later in the cliffs
of Mesa Verde.

There was a big explosion

in the kind of architecture
they were making

and its scale
and its sophistication.

There were already tens of
thousands of little communities,

but now they started building
these gigantic buildings.

We call them "great houses,"

and they were
apartment complexes

but on a scale
that the Pueblo had never made.

Hundreds of individual rooms

would make up
these great houses,

and they could be upwards
of five stories tall.

For years,

people studying the Anasazi
have wondered

how a simple group of people

developed into an advanced
civilization so quickly.

But perhaps an even more
intriguing question is:

Why would those same people

go to such great lengths
to build incredible structures,

only to abandon them?

And then, during the 1200s,

very mysteriously,
suddenly, it disappeared.

When archaeologists looked
at these remains

at the time of
the civilization disappearance,

it was very sudden, as if people
just grabbed what they could

and took off.

People just up and left.

They left behind
all of their belongings.

And there is evidence that this
activity occurred very quickly.

It was almost as if
they left behind ghost towns.

So, what really happened
to the Anasazi?

We know that drought
must have been a factor,

because there were periods

when there was
virtually no rain.

We can say
they left for drought reasons,

but if these
perfectly good places

were good again
after the drought,

why didn't they come back?

It had to be more than
just a practical.

"Well, we can't plant here
anymore."

If it wasn't drought

that forced the Anasazi
to leave their cliff dwellings,

then what was it?

According to
some anthropologists,

the answer may lie
in their own mythology

and a tale about
a shadowy supernatural figure

known as the Gambler.

The story of the
Gambler tells of a very powerful figure.

He challenges all the people
of the Four Corners region

to these gambling matches,
and he always wins.

And in these stories,

the people give away
their goods.

Eventually, they're giving away
even their homes and their food

and eventually themselves
as slaves

to this powerful gambler figure.

And in their mythology,

they say the Gambler
is the one who taught them

how to build these great houses

and asked them to do it,
basically,

in terms of slavery.

They were then his to command.

Eventually, in the story,

the gods decide that the Gambler
has overstepped.

He has become full of hubris.

He's behaving in a way
he shouldn't.

So he's eventually defeated
and banished from Chaco Canyon.

So, when the Gambler
was finally defeated,

it's said that he laid
some kind of curse on the land.

He said,
"I will kill you with lightning,

"and I will send war
and disease among you.

"May the cold freeze you.

"May the fire burn you.

May the waters drown you."

Some groups say he opened up
some kind of vortex.

And because there was so much
badness and so much suffering,

everyone made the decision
to leave

and never go there again.

Many cultures
have tales of a wily trickster,

someone who cheats people
out of hearth and home

before laying a curse
on their village

and vanishing
in a puff of smoke.

But could the Anasazi legend
of the Gambler

have actually been based
on a real‐life event?

I went into museum collections,

and I found hundreds
of gambling pieces excavated

from Pueblo Bonito and the other
buildings in the canyon,

things like dice or pieces used
in different guessing games.

There's a lot
of archaeological evidence

for gambling at Chaco Canyon.

And I do think
the stories are literal

in the sense that it was
a major aspect of the society.

It has to do with actual people,
historical events.

Does archaeological
evidence of gambling

mean the Anasazi legend
of the Gambler

is simply a parable about
the dangers of unchecked vice?

Or were the Anasazi forced
to flee from their homes

after being tormented
by some sort

of dark, supernatural force?

Very often, abandoned villages
or abandoned sites

are held to be haunted
by the ghosts.

This is probably
a very widespread notion that,

when a civilization collapses,

very often,
something went wrong.

And it's not purely physical.
It's something spiritual.

Today, Pueblo people
will go to Chaco,

and they will honor
their ancestors there.

But some groups of them say

that there was a very bad thing
that happened there

and that their ancestors,
for a long period of time,

didn't go there and they wanted
nothing to do with it.

Could a deadly curse
really have caused the Anasazi

to abandon
their elaborate cliff dwellings?

There are those who believe that
dark forces were responsible

and that similar forces
were also behind

the mysterious disappearance
of what might have been

the world's first civilization,

the one located
at a place now known

as Gobekli Tepe.

While plowing his field,

shepherd Safak Yildiz spots
a strangely shaped stone

emerging from the parched earth.

When he brushes away the dirt,

he realizes the stone may be
part of a much larger object.

After reporting his find,

he is visited
by archaeologist Klaus Schmidt

and a team from the German
Archaeological Institute.

Further excavation reveals

the stone is actually part
of a massive,

elaborately carved stone pillar,

one in what turns out
to be dozens

that form an ancient
underground complex.

Gobekli Tepe is
arguably the most important

archaeological discovery
in recent years.

We're talking about
a whole series of stone circles

built on the top of a mountain.

If you can imagine
Stonehenge in England

but multiply it by 20 times

and have these stones in circles

facing towards two massive,
great monoliths

as much as
18 and a half feet tall,

weighing between 15 and 20 tons,

this is what we see
at Gobekli Tepe.

Gobekli Tepe could very well be
the first lost civilization.

We've only uncovered
a small percentage of it,

like ten or 15%.

We have no idea, really,
how much bigger this is

and what else
we're gonna find there.

We have to ask ourselves:

Could Gobekli Tepe been

a place of commerce and trade?

And I think the answer
is an undoubted yes,

because its construction
would have necessitated

the presence
of not just hundreds

but many thousands of people
coming from across the region

who, at the beginning,
were hunter‐gatherers.

While there are many theories,

the true purpose of Gobekli Tepe
remains shrouded in mystery.

But no less mysterious
than the stones themselves

is the lost civilization
that fashioned them.

Because when sediment layers
of the site were carbon‐dated,

it was shockingly revealed
that Gobekli Tepe

is more than 12,000 years old.

Gobekli Tepe
really did send shock waves

through the whole world
of early prehistory,

because we'd never before
known or imagined, even,

that simple hunter‐gatherers

could produce such spectacular
monumental structures

as‐as are found at Gobekli Tepe.

Now, many of these pillars

also have remarkable carvings
on them, wonderful carvings

and bas‐reliefs of animals,
birds, insects,

all kinds of things.

So to fashion those
and carve them

and set them up
in these structures

was just absolutely amazing.

More than one‐third
of Gobekli Tepe's stone pillars

contain elaborate
bas‐relief carvings

of various animals.

But what has many archaeologists
and historians puzzled

is that many
of the species depicted,

like geese and armadillos
and wild boar,

are not indigenous to the area.

That location just happens
to be near where Noah

and the animals in the ark
ended the long journey

through the flood.

And these giant pillars
in Gobekli Tepe

have carvings of animals,
many different kinds of animals.

Are these the animals
from the ark?

Did the stories
about those animals

end up being depicted in stone?

Could there
really be a connection

between Gobekli Tepe
and the Great Flood?

Perhaps.

But according to
another audacious theory,

the animal carvings
at Gobekli Tepe

may have been inspired
by another,

even older biblical story.

Gobekli Tepe
is located in the very area

that the Bible tells us
the Garden of Eden was located.

It is said that Eden was where
the four rivers of paradise

took their rise.

Two of those rivers were
the Euphrates and the Tigris

that flowed through Mesopotamia.

And these both rose
in the same area

as Gobekli Tepe.

Professor Klaus Schmidt,
the German archaeologist,

even suggested himself

that this could be
the area of Eden

and the point of foundation
of civilization.

The Garden of Eden?

It's a fascinating theory

but one that is not
without its problems.

Because archaeological evidence
shows that Gobekli Tepe

was not only later abandoned,

but also backfilled
and deliberately buried.

Why...

would anyone want to leave‐‐
and bury‐‐

paradise?

Around 8000 B. C.,

the people of Gobekli Tepe
just vanish.

They just disappear.

So we have to ask ourself:
Where did they go?

Did they just vanish
into oblivion?

What we know is that recently
archaeologists discovered

a number of human skulls
that had been modified.

And what this means is
that they had been sculpted,

or that they had been pierced,

uh, so that they
could be hung up

perhaps on some kind
of frame or platform.

They found
skulls that are smashed in.

They found remains that look
as if there's been some kind

of mass ritual or murder
or sacrifice going on.

There may have actually been
a skull cult there.

Do we know
what these people were doing?

Of course not,
because they were doing this

thousands of years
before writing took place.

We can try and guess.

We‐we know important rituals
took place there.

Klaus Schmidt
would talk about this as Eden.

I think what he meant was
this is an Edenic society.

Because if you look at the story

of the Garden of Eden
in the Bible,

that's
a hunter‐gatherer society.

That's before we discover
agriculture.

And so the fact that here's
this place, Gobekli Tepe,

it's really challenging
our understandings

of our own origins,
our own religious origins.

And you start thinking about
what else we're gonna find.

It remains to be
seen what will be found

in the rest of the site.

But, certainly,
I'm sure Gobekli Tepe

has plenty more surprises
for us.

Every new enclosure excavated,

every new piece of evidence puts
another piece in the jigsaw

but also, at the same time,

raises new questions that we
find very difficult to answer.

Whether Gobekli Tepe has

a connection
to biblical stories or not,

one thing is certain:

Its builders chose to bury
their great creation,

and we may never know why
or where they went,

not unlike
another ancient civilization

that also buried
their most important artifacts,

giant stone heads that suggest

they might have possessed
the ability to harness

one of the most powerful forces
in the universe.

Archaeologist Matthew Stirling

is excavating an ancient site

once occupied
by the Olmec people,

a lost Mesoamerican civilization

dating as far back as 1200 B. C.

As Stirling's team unearths
and catalogs numerous artifacts,

they notice a number
of unusually large,

rounded boulders buried nearby.

What emerges from the ground
are, quite literally,

some of the largest
archaeological finds

of the 20th century.

Over the next several decades,

17 colossal heads
carved from solid basalt

were ultimately discovered
in the area,

the largest measuring
a staggering 11 feet tall

and weighing 50 tons.

When you walk up
to these imposing,

you know, stone monuments,

you see these things
are‐are huge,

with these just amazing
lifelike features.

It would have taken
thousands of people

to drag these stones
through the rainforest,

through mud and swamps,
onto the tops of their sites.

But perhaps what's
most striking about these giant heads

is not their size

or how they were brought
to the middle of the jungle

but rather who they seem
to be depicting.

The colossal heads have

an African appearance.

But, also, equally,

they've been seen to have
a Polynesian appearance as well.

Is it possible
that the Olmec were the result

of transpacific
or even transatlantic migrations

of peoples
from other continents?

Although mainstream
historians dismiss the notion

that the Olmec originated
in Asia or Africa,

the appearance
of the Olmec heads

suggests that it is possible.

But not only do we not know
where the Olmec came from,

we also don't know
where they went.

One of the real frustrations
to archaeologists

who study the Olmec

is that we don't have
a single Olmec skeleton

that we can look at and analyze.

For over a thousand years,

the Olmec were the culture
in the middle of Mesoamerica.

But then they faded away.

And why exactly they stopped

is something we're not sure of.

The Olmec
disappeared so completely,

all that's left of them
are scattered remains,

some sculptures and figurines.

Which means,
if we're to answer the riddle

of the Olmecs' disappearance,
there's only one place to look:

Those huge,
imposing stone heads,

staring back at us through time

with their odd,
sphinxlike gazes.

One of the most remarkable
discoveries

in connection with the art
of the Olmec

is the presence of magnetism.

In a number
of different statues,

when a compass
is brought up to them,

the needles move.

Archaeologists in the late 1960s
and early 1970s

used magnetometers to find many

of the most remarkable
colossal heads.

The Olmec heads

probably gave off
magnetic signatures,

because they're made of basalt,

a dense volcanic rock
that becomes magnetic

as it cools.

So, by making the heads
of basalt

that came
from the volcano itself,

that same energy

was inherited
by those colossal heads.

What all of this suggests
is that the Olmec

went out
and deliberately chose rocks

that had this magnetic effect.

Magnetic stones.

If the Olmec
were harnessing magnetism,

what were they using it for?

There are many theories
about how the Olmecs

may have used magnetism.

One interesting speculation
is whether they could have moved

some of the large stones
using magnetic levitation.

It's very simple to get magnets

to either attract
or repel each other

if their poles are opposing.

It's difficult to imagine even
using modern moving technology

to move very large stones.

Yet they were moved.

Levitation?

It's a fascinating theory,

although one
that's hard to prove,

not unlike another theory
that suggests

that the Olmec may have been
using the magnetic properties

in their giant stone heads
for healing purposes.

Colossal head ten from San
Lorenzo has what appears to be

these little
multiperforated beads

all over all of the head
in his headdress.

In a recent excavation, the lead
archeologists found thousands,

144,000 of
these little magnetic cubes.

And they could have been then
strung together in mats

and possibly,
in this case, the headdress.

And leading
some archeologists to say,

"What about
the magnetic qualities

that might have been used
in possible healing?"

We know the importance

of magnets used
in certain therapies.

And did the Olmec‐‐
did they already discover

the important health benefits
of‐of magnetic therapy?

If the Olmec leaders

were using the power
of magnetism

for some type of healing,

it may have had
the opposite affect.

Magnetic fields can be
healing or harmful.

In some cases,
people who have been exposed

to very strong magnetic fields

have lapsed into comas,
had seizures.

Some people have even died
after being exposed

to very strong magnetic fields.

So, could the presence

of magnetism in the art objects

that were fashioned
by the Olmecs

have had something to do

with why
they deliberately buried many

of their statues and figurines?

We do not have
any definitive answers.

But what we do know is

that the Olmec culture
dissolved.

It disappeared
almost into oblivion.

Did the Olmecs meddle
with magnetic powers

that were simply
beyond their ability to control?

Recent findings suggest

such a fantastic notion
is entirely possible.

Theirs is a cautionary tale

of technology run amok,
and, just like our next example,

the consequence
of trying to harness a power

far too deadly to be contained.

Located more than 2,000 miles

west of South America,

it is one of the most remote and
desolate islands in the world.

It is also the home
of nearly 1,000 moai,

a collection of giant
megalithic stone sentinels

whose purpose remains
as mysterious

as the lost civilization
that carved them.

Located in what is now Cambodia,

this enormous, 402‐acre
temple complex was once part

of the thriving city of Angkor,
the capital of the Khmer Empire.

Although most historians agree

that the Khmer people
were most likely vanquished

by a series of devastating wars,
the real reason

for their complete disappearance
is unknown.

Located on an island

in what is now Dare County,
North Carolina.

This English colony was
originally conceived in 1585

as part of Sir Walter Raleigh's
plan to settle North America.

When English explorers returned

to check in on the colony
in 1590,

they found that its estimated
121 inhabitants

had vanished.

The only clue they left behind
was the word "Croatoan,"

mysteriously carved into a tree.

All of these, and more,

are examples of civilizations
that simply vanished.

But why?

And how?

Perhaps the answer can be found

by examining
a more recent cataclysm,

one that forced an entire city
to be abandoned.

A magnitude
nine point earthquake

triggers a devastating tsunami

along the country's
eastern shore.

Giant waves up to 50 feet tall

are sent crashing
into the coast,

killing almost 16,000 people

and destroying hundreds
of buildings,

including the Fukushima Daiichi
Nuclear Power Plant.

As seawater pours
into the plant,

it triggers a chain reaction

that leads to
three nuclear meltdowns,

multiple hydrogen explosions,

and a massive flood
of radioactive contamination

into the surrounding area.

200,000 people
are immediately evacuated.

In less than 48 hours,
this once‐thriving city

becomes a ghost town.

An entire city

was abandoned

in the middle
of the Fukushima crisis.

Something like from

a post‐apocalyptic
science fiction movie.

Food still
on the shelf in stores.

People literally did not go down

into the house
to grab their coats.

They just got theirselves

and their family into the car
and drove

because of the danger
of radiation leakage.

The Japanese didn't

prepare adequately for tsunamis

because this was just
an unforeseen consequence

of a catastrophically large
earthquake.

The earthquake that caused
the tsunami was one

of the‐the nastiest earthquakes
ever recorded.

Nobody had envisioned this level

of catastrophe happening
all at once.

We know that no
one will ever go and live there again.

This place is gonna have to be
vacant for years

because it's radioactive.

We tend to think
that just because we live in a world

with advanced technology,
modern medicine,

and the ability to fly around
the world in a single day,

that our civilization is safe
from extinction.

But disasters,

like the one at Fukushima,
prove that is not the case.

I look at an event like
Fukushima and see a pattern:

That we are not that different

than the people
that lived in the past.

We have, as civilizations, again
and again created technologies,

and forgotten the power
of nature.

Civilizations disappear rapidly.

So we have to ask ourselves
whether, in past ages,

natural catastrophes
can have combined

with the presence
of human civilizations

to create cataclysms
that completely obliterated

entire civilizations.

Whether by natural catastrophe

or by war, famine or disease,

all civilizations, even our own,

are destined
not to last forever.

But is there any way to stop
the inevitable from happening,

or are we really doomed

to repeat the mistakes
of the past?

A panel of experts from
the Future of Humanity Institute

publish the results
of a survey regarding

the global catastrophic risks

that humanity will face
in the 21st century.

The results of the questionnaire
are both surprising

and concerning,

because the experts agree that
there is a one‐in‐five chance

of human extinction
before the year 2100.

At the 2008 Oxford conference,

participants considered
nanotechnology,

artificial intelligence and war
to be the three categories

that were most likely to
bring about such an event.

Personally, the one
that keeps me awake at night

is the unbridled development
of artificial intelligence.

It's partially because of
the weaponization

of artificial intelligence,

and what I like to refer to as
the dark triad of offensive,

lethal, autonomous machines.

The possibility
of programming errors

or of users deliberately
inflicting these

upon enemy populations is

the type of thing
that makes me nervous.

The development
of artificial intelligence

is supposed to make lives
a lot easier,

but in practice might represent

the biggest existential threat
of all.

When we see a civilization
that effectively disappears

without a record of
precisely why they left,

the answer is often rooted
in the development

of advanced technology,

because advanced technology
enables a larger population

to live in a smaller area.

But if something happens
to the resources themselves,

then you don't have the capacity

to support
the population anymore.

When I look at an episode like

Rome making an incredible
drainage system

out of lead pipes,
and then everyone goes nuts‐‐.

Is it all that different
than human society

building up technology
to the point where we forget

that we're really
just part of an ecosystem

that's much more powerful than
us no matter what we build?

We have a tendency
to assume that we can always

innovate our way out of
the crisis of the moment.

There's also no guarantee
that technology will save

a civilization when it's faced
with an existential threat.

Will we live to see the day

when our own civilization
comes to an end?

Given how advanced we've become,
it seems unlikely

that all of
our current technology‐‐

our cities, architecture,
culture‐‐

could ever be reduced to
a giant pile of rocks

and a few carvings,
but then again,

maybe it's our naive belief
that it can't happen to us

that makes our demise
inevitable.

So is there any way
we can prevent it?

Perhaps the answer will be
one more that for now remains

unexplained.

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