♪ ♪ <i> NARRATOR: Lost civilizations.
 Mysterious sunken cities.</i> <i> And legendary Atlantis itself.</i> <i> Vanished beneath the waves.</i> PATRICK: There is a
huge amount of unrecorded
human history beneath the ocean's surface that we don't
know very much about at all. <i> NARRATOR: Imagine if we
 could empty the oceans,
 letting the water drain away</i> <i> to reveal the secrets
 of the sea floor.</i> <i> Now we can, using the latest
 underwater technology.</i> <i> Piercing the deep oceans
 and turning accurate
 data into 3D images.</i> <i> Is this a huge
 underwater temple carved by a
 mysterious lost civilization?</i> <i> NARRATOR: Why are these
 perfectly circular stones</i> <i> lying at the bottom of
 a bay in the Aegean Sea?</i> SIMON: There are shapes
on the seabed that
just don't make sense. <i> NARRATOR: Are these just
 rocks, or the remains
 of an ancient city?</i> <i>JON (over radio): Parts of
this are just beginning to
be revealed for the first time.</i> <i> Wow.</i> <i> NARRATOR: And is the real
 site of Atlantis finally
 about to be revealed?</i> -People want to believe
in places like Atlantis. They want to believe
in other worlds. (waves crashing) <i> NARRATOR: Stories
 of sunken cities have
 fascinated for millennia.</i> <i> The most tantalizing
 of all: Atlantis.</i> <i> First described by
 ancient philosopher,
 Plato, a dazzling civilization</i> <i> destroyed by the gods as
 punishment for human pride.</i> -People connect to that story,
and it's because of this idea
of an ancient civilization, a utopia, that
we've evolved from. <i> NARRATOR: 2,000 years
 later, the idea of Atlantis</i> <i> continues to fascinate
 A-list archaeologists.</i> <i> And the producers
 of B-list movies.</i> <i> MAN (over TV): Atlantis is the
story of those who, like today,</i> <i> would use the
 marvels of science to
 conquer and enslave.</i> <i> Atlantis, a world
 that worships strange
 gods of science,</i> <i> of science, a
 science gone berserk.</i> -Plato would have
loved this okay? He would have
had a great time. He would have said, 'at
last, you know, people
are listening to me. People are taking
my story seriously.' And he would have
enjoyed this immensely. <i> NARRATOR: Using science,
 not science fiction,
 draining the oceans</i> <i> exposes new evidence
 about Atlantis.</i> <i> And other stories of
 great sunken cities,
 around the world.</i> <i> As the waters recede
 from around the remote
 Japanese island of Yonaguni,</i> <i> a mysterious formation
 begins to appear.</i> <i> Could it be the creation of
 an advanced, ancient people?</i> <i> Yonaguni lies in
 the East China Sea.</i> <i> The waters here are perilous.</i> <i> Schools of hammerhead
 sharks patrol, amid
 powerful currents.</i> <i> Typhoons frequently
 batter the island.</i> <i> For divers, it's the
 ultimate challenge.</i> <i> Kihachiro Aratake is one of
 the pioneers of diving here.</i> KIHACHIRO: The water
was crystal clear. I felt as though I was
looking down from the
seabed from the sky. <i> NARRATOR: Searching for
 a new dive site, he makes
 a startling discovery.</i> -I saw a steps-like formation,
like terraced fields. I thought for a moment
it was similar to the
Machu Picchu ruins. So, I named the spot
the submarine ruins. <i> NARRATOR: It's an
 extraordinary spectacle.</i> <i> The size of five
 football fields.</i> <i> Smooth-sided walls rise up
 to the summit, the height
 of an eight-story building.</i> <i> Flights of stone steps
 climb up from the base.</i> <i> And on every side, the
 shapes and forms are
 strikingly regular.</i> -It can't be formed naturally,
without human involvement. It couldn't be like that. <i> NARRATOR: So,
 what could it be?</i> <i> It's impossible to investigate
 the structure fully by diving.</i> <i> The only way is to conduct
 a survey using the latest
 scanning technology.</i> HIRONOBU: Although the shallow
waters around Yonaguni Island
are close to human habitation, we don't know much about them. It's an unknown frontier. <i> NARRATOR: Using sonar scans,
 Hironobu Kan records a</i> <i> complete digital map
 of the sea floor.</i> <i> Using this data,
 it's possible, for
 the very first time,</i> <i> to drain away the waters
 and reveal what lies
 beneath in exact detail.</i> <i> The summit of the
 mysterious structure
 begins to appear.</i> (waves crashing) <i> Water pours off its smooth
 terraced layers, exposing
 them once again to the sky.</i> <i> And with the monument
 left high and dry, its
 true scale becomes clear.</i> <i> Vast, imposing
 and spectacular.</i> <i> The incredible discovery
 attracts worldwide attention.</i> <i> Divers, journalists
 and TV crews flock to
 Yonaguni, all asking:</i> <i> what could this
 mysterious structure be?</i> <i> And scientists come here too.</i> <i> Among them is Professor
 Masaaki Kimura, one of
 Japan's top marine geologists.</i> KIMURA: When I dived
underwater to explore it I
felt right away that it must be a man-made structure. <i> NARRATOR: He finds several
 features that he believes
 indicate human activity.</i> -Here, you'll see
something that looks like
the front gate of a castle. It's like a tunnel,
and you go through it. <i> NARRATOR: On the far side
 of the tunnel, a road loops
 around to a flight of steps.</i> <i> Watched over by two
 mysterious stone objects.</i> -There are mound-like
bulges here and here,
and if you look at them, you'll find turtles with their
necks extended, on both sides. <i> NARRATOR: According to
 ancient Japanese folklore,
 the dragon god, Ryujin,</i> <i> lives in an underwater palace,
 watched over by turtles.</i> <i> To Professor Kimura, this
 indicates that the monument</i> <i> is so important
 it needs guarding.</i> <i> And that's not all.</i> -If you go up this path
you get to this place. This portion is triangular. That's why it's called
the triangle pool. Since this is fairly
big and shallow as well,
you can relax in it. Also, the sea surface is
very close to it and it's
warm due to the sunlight. You feel chilly after
you come out of the
deeper area down there, and you can warm up here. <i> NARRATOR: But the monument's
 most striking feature
 is its wide, flat terraces,</i> <i> Large enough to support
 thousands of people.</i> <i> Professor Kimura believes
 the gateway, stairs,
 turtles and terraces</i> <i> all point towards one purpose.</i> -Judging from its
shape, I think they
used it as a castle. <i> NARRATOR: But to prove his
 theory, Professor Kimura
 needs more:</i> <i> the artifacts of those
 who once lived here.</i> <i> He scours the structure
 looking for clues, and</i> <i> discovers what look
 like primitive tools.</i> <i> Then, hidden behind one of
 the great walls, the most
 remarkable find of all.</i> -Look at this,
a symbol is inscribed
here and here's a hole. Probably, they hung
this article like this. And here's something
looking like a letter. Maybe it could be a kind
of a talisman to protect
people from evil. <i> NARRATOR: For Professor
 Kimura, the case is closed.</i> <i> The artifacts and
 the monument's regular shapes
 prove that humans lived here,</i> <i> 8,000 years ago.</i> <i> After that, rising sea levels
 claim the territory of this
 lost race of master builders.</i> <i> But is that the real
 story of Yonaguni?</i> <i> NARRATOR: Professor
 Kimura believes that this
 extraordinary structure</i> <i> off the coast of Japan is a
 gigantic castle, built long
 before the pyramids of Egypt</i> <i> by a mysterious
 lost civilization.</i> <i> But is it?</i> <i>With the water drained away,
it's possible to scrutinize the
monument in forensic detail.</i> <i> The edges appear regular and
 straight, as if made from
 blocks carved by human hand.</i> <i> But closer examination
 reveals something else.</i> <i> The surfaces are
 smooth and unbroken.</i> <i> The monument is not assembled
 from handmade blocks,</i> <i> but is in fact one
 solid mass of rock.</i> HIRONOBU: The pyramid area
and the headland behind it
are connected with each other. The surface of the terrain
has a lot of grooves, so you
may think they are separate, but since they consist of
the identical stone, they
are originally connected. <i> NARRATOR: The basic
 form of the monument
 is clearly natural.</i> <i> But what about the gateway,
 steps, turtles and pool?</i> <i> Could it be that an
 ancient people carved
 into this huge rock,</i> <i> transforming it into a
 great castle or temple?</i> <i> Studying the headland on
 shore provides the answer.</i> <i> The shapes here are
 strikingly similar to
 those found on the monument,</i> <i> and that's because
 they were formed in
 exactly the same way.</i> <i> Both are made of
 sandstone which, when
 subjected to stress,</i> <i>such as during
an earthquake, can
fracture along vertical faults,</i> <i> forming angular shapes
 and what look like steps.</i> PATRICK: Put something like
that underwater, have the
water wash over the top of it and clear away all the debris,
and you've got very, very
fine step-like structures. But they're no more
human made than any other
structure down there. <i> NARRATOR: The lack of tool
 marks is further confirmation.</i> <i> The forces which
 shaped this remarkable
 place are geological.</i> <i> But what of the artifacts?</i> <i> Perhaps the monument,
 if not built by ancient
 people, was inhabited by them.</i> <i> Walking these steps.</i> <i> Crowding these
 natural terraces.</i> <i> But so far, no other objects
 have been found, suggesting
 that the talisman and tools</i> <i> were dropped from a boat
 passing overhead, landing on
 the monument simply by chance.</i> -The clear thing for Yonaguni
for me is there's no pottery, there's no evidence of
actual human occupation. There's not a single
wall from the site. There's nothing on it, that
indicates human activity. <i> NARRATOR: The Yonaguni
 Monument is an extraordinary
 natural formation,</i> <i> created by epic
 geological forces.</i> <i> But its shapes
 appear so regular
 that many still believe</i> <i> it holds a secret,
 ancient purpose.</i> JIM: You can take
that leap if you have an
imagination and say yes, this could be an ancient
city beneath the sea but
in the case of Yonaguni I'm in those ranks
that feel that it's not. It's geology. -We want to believe
that science doesn't
have all the answers. We want to believe innately
that there is something out
there that we can connect with spiritually and that hasn't
really been polluted by being the subject of
scientific discovery. <i> NARRATOR: And still
 amongst the believers
 is Professor Kimura.</i> <i> He remains convinced that the
 monument was inhabited by his
 ancestors and continues to</i> <i> search for evidence to
 prove the doubters wrong.</i> <i> Beneath the oceans of
 the world lie many more</i> <i> tantalizing traces of
 possible lost civilizations.</i> <i> As the water continues
 to drain away, in the
 Eastern Mediterranean,</i> <i> astonishing structures emerge
 in a quiet island harbor.</i> <i> Is this jumble of shaped
 stones the architectural
 debris of a once great city?</i> <i> Alikanas Bay, a tourist
 hotspot on the island
 of Zakynthos, Greece.</i> <i> Diver, Pavlos Voutos,
 sets out to take some
 underwater photos.</i> <i> NARRATOR: Pavlos swims
 farther out into the bay
 in search of clearer water.</i> <i> Then, out of the gloom,
 he sees something that
 will change his life.</i> <i> NARRATOR: The debris
 stretches out for hundreds
 of yards in all directions.</i> <i> The area is so large that
 Pavlos is convinced he's found
 the remains of an entire town.</i> <i> NARRATOR: The discovery sends
 a bolt of electricity through
 the world of archaeology.</i> <i> Professor Michael Stamatakis,
 immediately travels to
 Zakynthos to investigate.</i> <i> NARRATOR: Stamatakis recalls
 seeing similar shapes on land,</i> <i> at the site of an
 ancient settlement built
 over 2,000 years ago.</i> <i> NARRATOR: If the same shapes
 lie on the sea bed, they could
 indicate an ancient settlement</i> <i> just offshore concealed
 under the bay and forgotten
 about for centuries.</i> <i> Comparing the images
 is not enough.</i> <i> The only way to
 reveal a complete
 picture of the structures</i> <i> is a detailed
 underwater survey.</i> <i> Simon Brown is an
 expert in 3D modelling.</i> <i> But the task facing
 him is immense.</i> SIMON: Right now
we're not quite sure
how big the area is. I've estimated it's about
16 acres, which will be more than double the
largest subject I've
ever covered to date. It's a weird place. There is definitely features
here that I have never
seen anywhere else before. They look out of place. But then I started to see
more regular shapes that
looked that cut stone. So my mind then starts
to think, is it... is it manmade? <i> NARRATOR: Can draining the
 waters of the Mediterranean
 provide the answer?</i> <i> NARRATOR: Simon Brown
 is mapping mysterious</i> <i> underwater structures
 discovered in a Greek bay.</i> <i> Could they be the remains
 of an ancient town?</i> <i> He takes nearly 4,000 high
 resolution photographs of the
 sea floor tracking each with</i> <i> pinpoint accuracy through GPS.</i> <i> Using these images, it's now
 possible to do something which
 has never been done before:</i> <i> drain the waters of
 Alikanas Bay and reveal,
 for the first time ever,</i> <i> a 3D plan of the
 entire sea floor.</i> <i> As the Mediterranean begins
 to recede, a world is exposed</i> <i> that's been invisible
 for thousands of years.</i> <i> First, the rocky shoreline
 is left high and dry.</i> <i> Then, from the
 dark depths, regular
 shapes begin to appear,</i> <i> hidden amongst the rocks.</i> <i> Could they be the bases of
 stone columns which together
 once formed a grand colonnade?</i> <i> The use of colonnades is
 a turning point in ancient
 Greek architecture.</i> <i> Builders can now switch
 from wood to stone, a
 far stronger material,</i> <i> to create ever larger
 temples to the gods.</i> <i> A colonnade in Alikanas Bay
 would prove that an important,</i> <i> ancient settlement
 once stood here.</i> <i> But some experts
 remain skeptical.</i> PATRICK: There are structures
all over the world that mimic something that humans
may have created. Doesn't mean that
humans created them. <i> NARRATOR: With the water
 drained away, it's now
 possible to search the</i> <i> sea bed for evidence
 of human occupation.</i> <i> Fragments of the pots
 people cooked with.</i> <i> Charcoal from their fires.</i> <i> Tools for farming, and weapons
 for defending their homes.</i> <i> Any objects made of
 metal, clay or stone
 should have survived.</i> <i> But there's nothing.</i> <i> Which means
 these extraordinary
 remains, whatever they are,</i> <i> are not the relics
 of a lost town.</i> <i> So, what are they?</i> <i> NARRATOR: Further analysis
 reveals the formations
 are what geologists call</i> <i> 'concretions'.</i> <i> Solid blocks of
 sedimentary rock formed by
 powerful volcanic activity.</i> <i> Underwater vents
 release methane from
 deep within the Earth.</i> <i> Combining with
 microbes and sediment,</i> <i> the methane causes regular
 circular shapes to form.</i> <i> Far from being a
 relic of ancient Greece,</i> <i> the structures here
 pre-date human activities
 by five million years!</i> <i> Despite all the evidence
 against his theory,</i> <i> Pavlos Voutos remains
 convinced that the fantastical</i> <i> landscape he discovered
 was shaped by his ancestors.</i> <i> NARRATOR: Classical
 civilizations dominate the</i> <i> Mediterranean for
 over a thousand years.</i> <i> Today, all around
 its coast, people tell
 stories of sunken cities.</i> <i> As the waters around
 Greece drain away further,</i> <i> an extraordinary underwater
 vista is exposed.</i> <i> Could these patterns on the
 sea floor be the remnants
 of an ancient city?</i> <i> The village of Elafonisos
 sits on a small island
 just off the Greek coast.</i> <i> At first glance, an
 ordinary fishing port.</i> <i> But in 1967, less than 100
 yards out to sea, something
 attracts the attention of a</i> <i> visiting maritime
 archaeologist.</i> <i> Snorkeling in 13 feet
 of water, Nicholas Fleming
 catches a glimpse of</i> <i> regular shapes
 on the sea floor.</i> <i> Then, exploring deeper,
 he sees what he thinks is
 evidence of human activity.</i> FLEMING: I looked at these
rows of stones, and I just
had no idea what it was, but I realized immediately
that it was manmade, that
we were looking at a large part of a town, and
I mean I just went crazy. <i> NARRATOR: Fleming is
 convinced he has found
 something special.</i> <i> But could these simply
 be natural formations,
 mimicking human structures,</i> <i> like the concretions
 of nearby Alikanas Bay?</i> <i> The following year,
 Fleming returns with
 a team of surveyors</i> <i> to discover the truth.</i> <i> Using tape measures, they
 document what they find.</i> <i> And the results
 are astonishing.</i> <i> The site is strewn with
 signs of human activity.</i> <i> Pots, storage vessels
 and tools lie across a
 huge area of the sea bed.</i> <i> There can be no doubt:
 Fleming has discovered the
 remains of an ancient town.</i> <i> It's named Pavlopetri
 after a nearby island.</i> <i> But who built it, and when?</i> <i> These questions inspire a
 generation of archaeologists.</i> JON: Well I've always
been interested in submerged
settlement, submerged towns, and I'd read about
Pavlopetri as a boy. And this idea of an intact,
prehistoric town underwater
just seemed you know incredibly romantic,
incredibly exciting. <i> NARRATOR: Henderson can now
 fulfill a childhood dream
 and explore this haunted</i> <i> underwater world for himself.</i> -Here we have a quern stone. -You can see it's
got a very concave,
concave surface there. That's for grinding grain or
whatever it was that you were
turning into you know flour. That's quite a clear artifact. Very nice. There is a huge amphora. One, amphora, two amphora,
three, four, five. This gives you an example of
what's coming out of the sand, what's eroding out of the sand. Look, there's the base of an
amphora, there's the amphora
shape there, it's on its side. There's another one next to
it and another one there. <i> NARRATOR: And further into
 the bay, more evidence
 of human life, and death.</i> -So, here's a cist grave.
Edge set slabs. A very small one.
Possibly for a baby. There are about 40
of these on the site. <i> NARRATOR: Diving gives
 intriguing glimpses of</i> <i> objects lying
 upon the sea bed.</i> <i> But it's impossible to
 gain a complete picture.</i> <i> To do this, it must be mapped
 using the latest in underwater
 scanning technology.</i> (waves crashing) <i> Using this data, it's now
 possible to drain away the
 waters above Pavlopetri and</i> <i> bring sunlight back to
 a forgotten world and
 a true Sunken City.</i> <i> With the entire
 bay drained away,
 everything becomes clear.</i> <i> The lines are the
 foundations of buildings,
 laid out in clear streets.</i> <i> At the heart of the town is
 a large open area, perhaps
 an ancient market place.</i> <i> And nearby, the remnants
 of a huge structure, perhaps
 an important civic building.</i> <i> The remains cover 20
 acres and the town could
 have housed 4,000 people.</i> <i> A thriving, ancient
 settlement once existed here.</i> <i> The next challenge is to
 discover who built it.</i> <i> And when.</i> -We know how old the
occupation of the site is,
because we've got pottery. And pottery particularly
in this part of the
world is very well dated. What was really
exciting is we actually found
evicdence of pottery from the end of the Stone Age. So, we've actually got
occupation here from
about 5,500 years ago. And then we've got
every single bit of
pottery you would expect up until about 1100 BC. There's no gaps in that. So, the place seems to have
been continuously occupied
throughout the Bronze Age. <i>NARRATOR: Pavlopetri was
occupied for 2,400 years during</i> <i> a revolutionary period
 of human development.</i> <i> At its peak in the bronze age,
 around 1700BC, it looked like
 this: a perfect example of the</i> <i> time when Europeans start
 to live in stone-built towns
 with regular laid out streets.</i> <i> But one question remains.</i> <i> Why did the builders of
 this town choose this
 particular location,</i> <i> in a remote part
 of ancient Greece?</i> <i> Exploring the
 drained landscape
 around the ancient city</i> <i> reveals an all-important clue.</i> <i> At its edge, a huge sand bank
 stretches out into the ocean.</i> <i> During the Bronze Age,
 people don't build
 ports out of stone.</i> <i> They bring ships up to the
 shore and then beach them.</i> <i> And Pavlopetri's location
 means it can exploit the trade
 routes that boom during the</i> <i> Bronze Age right across
 the Mediterranean.</i> <i> Evidence of early commercial
 activity is everywhere.</i> -The interesting thing is
we've clearly got a lot
of material coming in. We found thousands
and thousands of shards of
very large storage vessels, which have been used for
storing olive oil, wine, that kind of thing and
generally anything. They were like the
containers of the day. <i> NARRATOR: And that's not all.</i> <i> Pavlopetri is also a
 hub for manufactory.</i> -We've got a lot of
evidence for loom weights,
thousands of loom weights, way more than you would need
for domestic production so it
seems that maybe textiles were something that were being
produced on the site
and perhaps exported. <i> NARRATOR: Pavlopetri is an
 extraordinary, bustling,
 vibrant port city.</i> <i> And an important
 center of trade.</i> <i> So how did such an advanced
 metropolis meet its end?</i> <i> NARRATOR: An ancient,
 submerged city off
 the coast of Greece.</i> <i> How it came to lie on the
 sea floor is a mystery.</i> JON: One of the interesting
things about Pavlopetri and
its submergence is that there are no historical
references to it at all. It sunk under the waves
and then it was out
of sight, out of mind. And there's certainly no
classical sources that
refer to its sinking. And there's nothing until
it's discovery really
in the 20th century. <i> NARRATOR: Scanning
 the drained bay could reveal
 what happened to Pavlopetri.</i> <i> At the edge of the town,
 it's possible to make out
 three mysterious lines.</i> <i> These are strips of beach
 rock, formed by the action
 of sunlight on salt water.</i> <i> They form only
 near the shoreline.</i> <i> It can mean only one thing:
 earthquakes caused this land
 to subside into the sea.</i> -So, there was a big
earthquake, perhaps part of
the remains went under the water, part of them are
still surviving, then there
was another earthquake it was pushed under then there was
a third, and it was gone. <i> NARRATOR: Pavlopetri is one
 of the most important Bronze
 age sites in the world,</i> <i> and the oldest submerged
 town ever discovered.</i> <i> But it's not alone.</i> -A lot of the major finds in
the next couple of decades are
going to come from the sea. I think we have the
potential to rewrite what
we know about human history. <i> NARRATOR: Pavlopetri is an
 extraordinary find, but it is
 not the legendary Atlantis.</i> <i> Various locations for
 Plato's dazzling city
 have been proposed,</i> <i> around the world.</i> <i> But most academic
 investigations point to one
 place: the Mediterranean.</i> <i> As its waters continue
 to drain away,
 at its western end,</i> <i> new and tantalizing
 evidence is revealed.</i> <i> Could archaeologists
 finally have found the site
 of Plato's famous lost city?</i> <i> Marc Gutscher
 is a geophysicist, long
 fascinated by Plato's story.</i> MARC: I do think that
becoming interested in
Atlantis can be almost, like a bug or an infection
or like gambling. I think one can
become obsessed. <i> NARRATOR: Plato wrote about
 Atlantis in 360BC, describing
 an advanced metropolis</i> <i> 9,000 years before his own
 time, lost beneath the waves
 in a cataclysmic event.</i> <i> Marc Gutscher has analyzed
 Plato's texts, searching
 for clues to its location.</i> -'This power came forth out
of the Atlantic Ocean from an
island situated in front of the straits which
are by you called the
Pillars of Heracles.' <i> NARRATOR: The Pillars of
 Heracles is the name given by
 Plato to the maritime boundary</i> <i> of the ancient Greek world.</i> <i> Many locations have
 been suggested.</i> <i> But Marc believes he
 has the answer: The
 Straits of Gibraltar.</i> -So here at Cape Spartel we're
at the northern edge of the
Moroccan Atlantic coast and just at the entrance to
the Straits of Gibraltar. About 10 to 15 kilometers
off to the north west
there's a submerged bank. Some people have suggested
that it might have been
inhabited and it might have formed the origin of
the Atlantis legend. <i> NARRATOR: Today, this area
 sits under the second busiest
 shipping route in the world,</i> <i> a difficult place for
 sub-sea investigation.</i> <i> During a project to study
 rising sea levels here,
 Marc gets his chance.</i> <i> Using a remotely operated
 vehicle or ROV, he sets
 out to map the sea floor.</i> (waves crashing) <i> It's challenging work.</i> -It was very difficult,
both the towing of the
camera was difficult, keeping the ship in place
was difficult, and especially
trying to keep the ROV in place was really,
really difficult. <i> NARRATOR: Finally, Marc
 gets the sonar scanning
 data that he needs.</i> <i> Now, combining
 this information with the
 latest computer graphics,</i> <i> it's possible to drain away
 the sea water from between the
 ancient pillars of Heracles,</i> <i> and attempt to solve one of
 the greatest archaeological
 mysteries of all time...</i> <i> Soon, rocks begin
 to emerge, and the</i> <i> unmistakable outline of an
 island gradually appears.</i> <i> Is this the site of
 Atlantis, exposed for the
 first time in 11,000 years?</i> <i> Once again, important clues
 lie in Plato's own writing.</i> -Plato says that the city, and
all of its war-like men, were
destroyed in one day and night of terrible misfortune,
caused by strong
earthquakes and floods. <i> NARRATOR: The island revealed
 by draining the ocean,
 sits on a subduction zone,</i> <i> a boundary between the huge
 tectonic plates that make
 up the Earth's surface.</i> <i> The exact point where the
 biggest earthquakes strike.</i> <i> A series of powerful
 earthquakes and tsunamis could
 have obliterated Atlantis and</i> <i> sent the island
 on which it rests down
 into the ocean depths.</i> -You could imagine that during
great earthquakes there might
have been some subsidence, so if we were to take into
account maybe 20 or 30 meters
of subsidence due to those earthquakes, there might
have been a somewhat
larger island there. <i> NARRATOR: The geology
 supports Plato's account of
 the destruction of Atlantis.</i> <i> But one other vital piece
 of evidence is still needed.</i> <i> NARRATOR: Draining
 the ocean has revealed
 a mysterious island</i> <i> exactly where Plato
 said Atlantis would be.</i> <i> But one other piece of
 evidence must be present for
 it actually to be Atlantis:</i> <i> The remains of substantial
 man-made structures.</i> <i> Using the drained landscape,
 it's possible to study
 the island's surface</i> <i> in extraordinary
 three-dimensional detail.</i> <i> Searching carefully for
 the remains of walls,
 temples, bridges,</i> <i> and anything constructed
 by human hands.</i> <i> But there are none.</i> <i> Nowhere on this mysterious
 island are there any lines or
 geometric shapes which would</i> <i> indicate the presence of
 a great, ancient city.</i> MARC: Atlantis did not exist
in the tiny island of Spartel. If it did exist traces of
it have not been found. <i> NARRATOR: However, the
 story of this submerged
 island is not over yet.</i> <i> There may be no trace of
 a city built out of stone.</i> <i> But evidence found on
 land nearby suggests that
 during the Stone Age,</i> <i> when sea levels were much
 lower, people did live here</i> <i> and in many other
 places just like it.</i> <i> And during this period,
 our human ancestors make
 some of the most important</i> <i> breakthroughs of all time.</i> <i> They learn how to farm,
 keep domesticated animals,
 use sophisticated tools,</i> <i> build wooden houses
 and begin to trade.</i> <i> Then, the last Ice
 Age comes to an end.</i> <i> Over the course of
 15,000 years, sea
 levels rise by 400 feet.</i> <i> And the territory of these
 early people vanishes.</i> <i> Their tools, homes and
 weapons are washed away.</i> <i> That elemental human story
 may help explain the timeless
 appeal of the Atlantis legend.</i> PATRICK: There are many,
many stories out there in
the world that recall times when land that was once
inhabited was submerged. Did that information
inform Plato's fiction
about Atlantis? JON: I think there's no doubt,
that almost every culture
in the world has a flood myth, a deluge story, because
we developed, as a species, within this period
of rising sea level. So, that for me, is so
fundamental to understanding
ourselves as a species, that we should be
looking into this. <i> NARRATOR: Plato's story of
 Atlantis is about human folly</i> <i> and the destructive
 power of nature.</i> <i> Today, the rising level
 of the oceans threatens
 all coastal communities.</i> <i> Great port cities like
 Bangkok, Ho Chi Minh City
 and Dhaka are all at risk.</i> <i> And in North America there's
 one of particular concern.</i> <i> New Orleans.</i> <i> Sitting on the banks of the
 great Mississippi River,
 the city's average height</i> <i> is six feet below sea level.</i> <i> This makes it highly
 vulnerable to flooding.</i> <i> In 2005, disaster strikes.</i> <i> Hurricane Katrina
 causes a massive storm
 surge and the levees,</i> <i> designed to protect
 the city, are breached.</i> <i> The resulting floods
 are catastrophic.</i> <i> Nearly 2,000 people die and
 many more are left homeless.</i> <i> And the situation in
 New Orleans is getting
 worse, because the</i> <i> city itself is sinking.</i> <i> Due in part to the removal of
 groundwater, some districts of</i> <i> New Orleans are subsiding
 by two inches a year.</i> JIM: Given ongoing
sea level rise, which
is a scientific fact, the time will come when
some of our settlements in
our time are under water. Cities like New Orleans,
they all have suffered
incursions of water. And the time will come when
we will no longer be able
to battle that incursion. <i> NARRATOR: By the turn of the
 next century, New Orleans
 could be uninhabitable.</i> <i> A mysterious underwater
 city, studied by
 maritime archaeologists.</i> <i> A modern-day Atlantis.</i> Captioned by Cotter
Captioning Services.