>>NARRATOR:
The oceans are a graveyard

of man's seafaring journeys.

Today, underwater archaeologists
are scanning the sea floor

for clues to our maritime past.

>>It's pretty amazing
what can be reconstructed

about people's lives by looking
at the few artifacts.

They look like trinkets
to us today,

but they help illustrate
the past in ways

that we haven't seen before.

>>NARRATOR:
Some explorers are using

state-of-the-art equipment
to survey the bottom

of the ocean.

Others rely on skilled divers
to map unknown shipwrecks.

>>You have to have
a trained eye.

You have to look for those
odd shapes, those colors

that don't occur in nature.

>>Every little piece down there
is a piece of a map,

a piece of a puzzle.

It's like a detective story
when you go down;

you're getting all these
little clues.

>>NARRATOR: Once retrieved,
experts meticulously conserve

centuries-old artifacts
from their watery grave,

hoping to identify
their origins.

With history preserved
in a liquid time capsule,

what stories will archaeologists
uncover?

Can they piece together the past
from tiny clues found today?

>> Major funding for this
program was provided

by the Batchelor Foundation,

encouraging people
to preserve and protect

America's underwater resources.

And by Divers Direct,
inspiring the pursuit

of tropical adventure
scuba diving.

>>NARRATOR: It's springtime
in South Florida,

and members from

the National Association
of Black Scuba Divers,

or NABS, are in
Biscayne National Park

for their annual DWP
training workshop.

>>DWP stands
for "Diving With a Purpose."

>>NARRATOR: Divers attend
the week-long workshop

that teaches volunteers
some of the basic skills

of underwater archaeology.

Ken Stewart is the program's
director and co-founder.

In 2004, he created DWP with
Biscayne National Park's

former archaeologist,
Brenda Lazendorf.

>>She was the only person
in the park,

and that she needed some help.

>>NARRATOR:
Located just south of Miami,

a majority of the park's 173,000
acres is covered by water.

Within its boundaries,

there are approximately 75 known
submerged archaeological sites.

>>Anything that humans
have modified and left behind

is potentially...
is an archaeological site,

and potentially a significant
one that tells the stor

of the park that we want
to interpret.

>>NARRATOR: Chuck Lawson is the
park's current archaeologist

and sole member
of the cultural resources team

at Biscayne National Park.

>>For the most part,
I'm not able to mobilize

the team big enough
to do decent documentation

on the shipwreck sites.

So DWP was created
by my predecessor

and the members of DWP
to help augment the work force

at Biscayne National Park.

Biscayne National Park
has been working

directly with DWP annually
for eight years.

>>We start out the first day
with just kind of an overview

of archaeology artifacts
and basic principles

of underwater archaeology
in general.

And that afternoon,
we do a mock wreck site.

>>Swim to the other end.

I'm going to come
straight through here.

>>We actually teach things
that you will actually do

in the water.

>>We always have to make sure
we have it taut.

>>That's correct.

>>So the first day
is very intense, very long.

>>NARRATOR: The next morning,
the DWP-ers load up

and head to Ledbury Reef,
an unidentified shipwreck

that Chuck has selected
for their training site.

>>The biggest part
of this training

is actually diving
on these wreck sites.

Most shipwrecks
are scattered debris fields.

>>NARRATOR: To an untrained
eye, historical shipwrecks

are often difficult to spot.

Years of exposure can destroy
a ship's structure,

and, with time, the remains
are buried in sand

or are overgrown with coral,

making the archaeological
research more challenging.

>>When a ship first wrecks,
there are a number

of environmental factors
that act upon

their rapid deterioration.

However, eventually, what's left
of the archaeological site

comes to equilibrium
with the environment,

and, at that point in time,
they may stay stable

for hundreds of years.

We're an agency with a mission
to preserve and protect.

We want to protect these sites
in situ.

Like I said, they are not
at risk of deterioration

unless they are manipulated,
and it is only done after

a lot of consideration on what
the value in the research is.

>>The first day we get
in the water

we do what we call
like a reconnaissance dive

or just kind of get an overview
of the size of the shipwreck.

So we'll run a baseline,
which is just basically a rope

from one end to the other,
and we try to run it down

the middle of where
all this debris field is.

And we would split the wreck
site up into four quadrants,

and we would actually
assign teams to each one

of those quadrants.

We have DWP-- Diving
with a Purpose-- instructors

with each team that would
be leading and teaching

those students.

We actually place what we call
"pin clips" along the baseline.

The pin clips are in increments
of feet, like ten feet, 20 feet,

30 feet, 40 feet.

>>NARRATOR: Once the baseline
and quadrants have been set up,

the volunteers search
the wreck site for objects

that might be
of historical significance.

>>We have what we call
"pin flags" that we place

around a wreck,
and we place those pin flags

to areas of interest.

It could be artifacts
or pieces of the wreck.

We have to know where
those artifacts are in relation

to the wreck, to the baseline.

So we take what are called
trilateration measurements.

Basically, you measure
the distance from that pin flag

where that artifact is located
to a baseline clip;

you'll do two measurements,

and that will actually
triangulate

and tell you exactly where
that particular artifact is.

>>NARRATOR:
After measurements are taken,

divers begin their "in situ"
or underwater drawings

of the objects they flagged.

These drawings will later be
transferred to a large site map

that illustrates the layout
of the wreck site.

After two days of diving,
the volunteers return

to the classroom.

They discuss their findings...

>>It clearly appeared
to be a joint, double-ended,

and it was made of metal.

>>NARRATOR:
...refine their drawings

and begin work on the site map,

which depicts
the entire wreck site.

>>They're learning how
to put the flag pin-points

on the map using the compass.

That's the old fashioned way;
of course, I use the computer,

so they can see how mapping
is done.

>>We used to do little sketches
on the site map, too,

but Gayle Patrick,
who's been working with us,

she's an architect,
and she has been able

to take those student drawings,
scan them using a CAD tool,

a computer aided design tool,
actually put those

in situ drawings
on the maps themselves, too.

>>NARRATOR: The volunteers
continue diving and working

in the classroom
for several days

until the site map is complete.

The finished map
is a valuable resource

for park officials who can use
it as a reference tool

for management decisions.

>>The first year,
it was just three of us

that finished the program.

And I would say by the end
of this year,

we'll have trained almost
80 advocates

in underwater archaeology
in eight years.

>>NARRATOR:
Dinizulu Gene Tinnie

is a Miami artist whose
creations are influenced

by the Middle Passage.

>>The Middle Passage
is the name that was given

to the Atlantic,
the transatlantic slave trade.

Trade goods from Europe
were taken to Africa,

traded for people.

The people were then transported
across the ocean

from the west coast of Africa
to the Americas.

And in the Americas,
they were sold

and the ships were then loaded
with the products

of slave labor-- cotton, sugar,
tobacco, indigo, rice, coffee,

so forth-- and then taken back
to Europe.

>>NARRATOR: Few artifacts
from this brutal chapter

in the history
of the New World remain.

In Key West, Florida,

the Mel Fisher Maritime Heritage
Society and Museum

displays a rare collection
of items recovered

from a slave ship called
the "Henrietta Marie."

>>Probably the signature
artifact from

the "Henrietta Marie"
are the shackles.

There are also a lot
of trade goods;

things like iron bars...

glass beads...

and pewter.

It was the first slave ship
that really gives us a snapshot

of what the slave trade
was like,

how it was organized and how
a slave ship functioned.

>>NARRATOR:
First discovered in 1972

in the waters off Key West,
the "Henrietta Marie"

was finally identified
nearly ten years later

when divers uncovered
the ship's bell.

In 1993,
the National Association

of Black Scuba Divers laid
a plaque in sanctuary waters

to honor those captives
who were brutally transported

aboard the "Henrietta Marie."

And the "Henrietta Marie"
wasn't the only slave ship

which sunk in Florida waters.

More than 100 years later,
the "Guerrero" was sailing

for Cuba with more than
500 captive Africans on board.

>>When we look
at the "Henrietta Marie"

sailing in 1700,
the slave trade was legal

and it was an accepted business.

When we look at a ship
like "Guerrero,"

that vessel is operating

in entirely different
circumstances.

>>NARRATOR:
While slavery was still legal

in the New World,
several countries,

including the United States,
Great Britain and Spain,

banned the transatlantic
transportation and sale

of slaves by the early 1800s.

However, demand for free labor
was still high

on Cuba's plantations,
and the now illegal slave trade

from Africa continued
on pirate ships.

At the time, the British Navy
patrolled the waters

for pirates.

One evening in 1827,
the British warship "Nimble"

spotted the "Guerrero"

and chased it towards
Florida's coast.

>>The "Nimble" started
chasing them.

They were going
at a pretty good clip.

A gun battle broke out.

In the excitement,
they weren't paying attention

to where they were.

They both slammed headlong
into the reef.

The "Guerrero," her bottom
was torn out;

her sails both flew forward
and was finished;

never moved again.

>>NARRATOR:
41 of the captured Africans

perished when the ship
went aground.

>>The "Nimble" threw over
iron ballast ingots,

threw over cannon shot
just to lighten their load

and be able to float
off the reef.

>>NARRATOR:
However, according to reports,

the "Nimble's" anchor line
parted, drifting them back

onto the reef.

The next morning, salvage crews
known as wreckers

towed the British ship
off the reef and provided aid

to survivors aboard
the "Guerrero."

>>That evening, the pirates who
were on a couple of the wreckers

rose up and wound up hijacking
the wreckers and getting to Cuba

anyway with 400
of the African people.

>>NARRATOR:
The hijacked wreckers

were eventually released
and returned to Florida.

121 of the rescued slaves
aboard a separate wrecker

were brought to Key West.

>>They were going
to be liberated at some point

from their intended slavery.

That was the U.S. law.

>>NARRATOR: Years later,
some of the rescued captives

returned to Africa.

>>It should be dead ahead.

>>NARRATOR:
Today, archaeologists

from the Mel Fisher
Maritime Museum

and the Florida Keys
National Marine Sanctuar

are trying to identif

the "Guerrero's" final resting
place.

Luckily for researchers,
the "Nimble's" captain

took notes of their
watery location,

which was near modern-day
Key Largo.

>>He took a bearing
from what was called

"Black Sarah's Creek,"
and he took another bearing

from the "Carysfort" lightship.

>>NARRATOR: With the help
of archival records,

researchers think they
have located

what used to be called
"Black Sarah's Creek,"

and from there have pinpointed
potential wreck sites

using a magnetometer.

>>The magnetometer is a device
that we use that measures

variations in the earth's
magnetic field caused by iron,

and that iron is either
a shipwreck or cannons

or anchors or something
like that.

We found four shipwrecks,
but one in particular

was pretty interesting.

>>NARRATOR: During one of the
magnetometer surveys,

experts discovered
a large anchor.

>>It matches exactly the sort
of anchor that "Nimble"

would have carried.

It's the right size,
it's the right date.

Doesn't have a name on it
that we can see,

but it matches everything.

>>NARRATOR: While they can't
say for certain that the anchor

belonged to the "Nimble,"
researchers think it's likely,

and they have started studying
a nearby site they believe

might be the "Guerrero."

They are joined in their efforts
by the DWP volunteers,

who have been involved
in the search for the "Guerrero"

since 2010.

>>This particular wreck
is different from all the rest

of them because there
were slaves on this one

when it went down;
there weren't any slaves

on the "Henrietta Marie"
when it went down.

>>For a lot of people,
it was about being where

their ancestors lay and
just being a part of history.

>>You know, it's the
little clues that are making

a difference on this wreck--
the single fragment of pottery,

or the single bottleneck,
or the single piece of metal.

>>You know, people have this
cartoon notion of shipwrecks,

and they think that,
you know, we dive down

and there's a ship
sitting there.

And there are skeletons
laying on the deck

and tattered sails and,
you know, maybe a shark

swimming in and out of the hull.

That's for aquariums, you know.

That's not real life.

We're left with basically
the hard things--

the ballast stones,
the iron fasteners,

the fittings, copper nails,
pottery, the glass--

the things that the critters
can't eat.

One of the things that we know
about the "Guerrero" is that

its hull was sheathed
with copper.

We found pieces of copper
sheeting crumpled and rolled up.

Copper corrodes in a very
distinctive, greenish way.

>>NARRATOR:
This site is located

in the Florida Keys National
Marine Sanctuary,

which aims to safeguard
the maritime histor

found in its waters.

>>In the Florida Keys,
shipwrecks are protected.

We want to have our next
generations protect and promote

the stories that lie within
and around these ships

that came into the coast.

>>NARRATOR: By law, artifacts
can't be brought to the surface

without special permits.

At times, permission is given
to researchers to remove items

for further study
and conservation.

During the 2010 expedition,
select items from

the wreck sites were brought
to the conservation lab

at the Mel Fisher Museum.

>>What may have been a dish,

you know, a full-sized dinner
plate is now a fragment

of a full-sized dinner plate.

Because this has a scalloped
edge like this,

this sort of rough undulating
edge that was a style

that reached its peak popularity
in the 1820s,

so that matches very closely
with what we're looking for

in the wrecks.

Another piece that we recovered
from the site

is a glass bottleneck;
it's from a very large glass jar

called a "demijohn."

It was just completely covered
with coral and algae,

so, to get it to this state
required a fair amount of work

using a sharp blade

and just sort of prying it off
of there.

We can't date it as precisel

as we can this blue and white
ceramic, but, nonetheless,

it's pretty easy to imagine
a big bottle of rum

onboard a pirate ship.

>>NARRATOR: Special care needs
to be taken with each item

to keep it from deteriorating
after it has left the water.

>>Every material type has
its own conservation needs,

so there's no one-size-fits-all
treatment in the laboratory.

With a metal object, we use
what's called an "air scribe,"

and it's like this
little air-driven chisel

that just chips the encrustation
off a little bit at a time.

Once that's done,
it goes into a tank

that has this
electrochemical process.

We call it
"electrolytic reduction,"

and really all it is doing
is forcing the salt

out of the metal,
because if we left them in,

the combination of the salt,
the oxygen and the metal

would just corrode the piece
to the point that

it was totally destroyed.

Right now, we have a shipwreck
that we know is

from the early part
of the 1800s.

It matches everything that
we know about the "Guerrero,"

but we don't have
the smoking gun yet.

We are looking for that
one thing that will just cement

the case for us and
we go from thinking

it's the "Guerrero" to knowing
it's the "Guerrero."

>>NARRATOR:
Maritime archaeolog

is conducted
in many different ways.

In shallow water,
divers can study a site;

but in deep water,
experts use high-tech tools

to survey the sea floor.

Ian Koblick and his team
from the Aurora Trust

map the ocean bottom
with a side-scan sonar

they like to call "The Fish."

>>We let out enough two cable
so the Fish is 15 feet or so

off the seafloor,
and it emits sound signals

out either side of the Fish.

And those sound signals
reflect off of objects

on the seafloor
back to the Fish,

and they register as a target
on our instruments

here on the boat.

>>When you emit that sound,
it's called a "ping,"

and every ping that comes back
you can display it across.

It's like scan lines
on a TV;

it all laces together
and makes an image.

>>Aurora, we started out
doing archaeological work

in the Mediterranean,
finding shipwrecks.

And then we set up
an educational program

to teach kids
about the importance

of the ocean
through marine archaeology.

>>NARRATOR: The Aurora Trust,
which specializes

in underwater exploration,
is also working

in the Florida Keys
National Marine Sanctuary.

>>We're making a map
of the bottom of the ocean

that shows corals,
geological features

and historical, cultural
features like shipwrecks.

>>NARRATOR:
Using a low-frequency signal,

analysts can see up to 500 feet
out from either side

of the Fish.

>>Generally, we can see
the difference between geolog

and something manmade
with the high-frequency.

This is a big coral reef
that's coming out right now.

You know, we've got sand
over here and a coral patch

right here, and there's
a big coral reef here,

so we're coming into
a strong reef area.

These are sand ripples
over in here.

>>Today's technology allows us
to go down with ROVs

and everything is electronic so
that you get a complete picture

of what's on the bottom.

>>NARRATOR: An ROV, or remotely
operated vehicle,

allows technicians to get
a closer and clearer view

of objects that
are hard to reach.

>>It's a little robot
at the end of the cable

that swims around and is guided
by an operator in the boat.

>>Yeah, it looks like I have
the bow of the wreck in sight.

>>NARRATOR: To demonstrate
its abilities, Chris Olstad,

an underwater technician

for the Marine Resources
Development Foundation,

deploys the ROV
on the Benwood Wreck,

a well-known dive site
in the Keys.

>>You have a thruster control,
and when you push the joystick,

the vehicle goes, essentially.

For vertical, you can tilt
the camera up and down.

You've got a focus adjustment,
you've got lights here

for night or diving in caves,
maybe inside the wreck.

We have an option
for a manipulator

to grab something
at depth, bring it back,

and I've also got
a recorder here

so I can record the video that
you are seeing on the monitor.

This particular unit
I have right now,

it goes down to 500 feet.

Another model, the same size,
it goes down to 1,000 feet.

>>NARRATOR:
Although remote sensing tools

can provide incredible access
to underwater sites,

surveying the ocean bottom

is tedious
and time-consuming work.

>>We have only begun.

We're able to cover about
a half a square mile a day;

we've been out about ten days,
so we have a long ways to go.

>>This is a great opportunity
to continue on with something

that I think makes
a contribution to societ

and to history,
and I love to do it anyway.

>>Shipwrecks and maritime
archaeology, I think,

brings history to life in a way
that people can't imagine.

>>There's a story
behind each ship;

some of them, it tells where
they were coming from

and what they were carrying.

The remains of these ships
are a vital part

of the Keys history.

>>You know, we can read about
the slave trade all we want,

but when you have something
that you know was onboard

a slave ship or was held
in a pirate's hands,

that is powerful, and it
makes it that much more real.

>>NARRATOR:
With countless artifacts strewn

across the oceans,
researchers will continue