Original subtitles

What could be more dangerous than the waters off Florida than sharks? Two

Josh. Nazi submarines.

There were three ships that were torpedoed by the Nazis, and one of them

still missing.

The Norlindo. Yeah.

Let me make sure I got this right. You want to use sharks to find a shipwreck?

That's exactly what I want to do.

You are going to be in the water with more sharks than you have ever seen on

of your other dives combined together.

There's a fall shark!

And another!

We need to catch a shark?

Yeah. Sounds safe.

It's shark camp.

The shark is going to be showing us where these wrecks are.

He's got it. He took it. We know where they're going and what they're seeing.

literally bit this hook in half. Look at this structure. This thing is huge.

Look out. He's turning this way.

There's something in front of us. There's a wall. Oh, my God.

Welcome to the Florida Keys.

Sure, it looks like paradise, but beneath the surface of the Gulf of

one of nature's fiercest hunting grounds.

The deadly bull, tiger, and great white are among the 25

shark species that prowl these waters.

But for eight terrifying months at the start of World War II, sharks are

overshadowed by a far more dangerous threat, Nazis.

Up and down the eastern seaboard and shockingly close to U .S. shores, German

submarines aggressively attack Allied merchant ships carrying vital supplies.

And on May 4, 1942, the Gulf sees its first combat casualties of the war when

Nazi U -boat torpedoes three American vessels.

Sixty -two sailors are lost at sea. Easy pickings for hungry bull and tiger

sharks.

And the SS Norlindo.

SS Joseph M. Cudahy and SS Munger T. Ball sink to the seafloor with hundreds

thousands of gallons of oil and fuel trapped inside them. The other two ships

have been located, but the Norlindo and her trapped fuel remain lost.

A hull breach could be an environmental disaster, threatening essential shark

breeding and hunting grounds.

This is a dangerous mission with deep dives and deadly predators.

But I'm joining eminent shark behaviorist Dr. Tristan Guttridge to

the missing tanker, to reveal a lost story from World War II, and to protect

sharks of the Florida Keys.

The past is all around us. Oh, this is crazy.

A world of mystery.

This is a plane. Yeah.

Danger.

We are about to be underwater.

and adventure.

I travel to

the far corners of the Earth to uncover where legends end and history begins.

I'm Josh Gate, and this is Expedition Unknown.

My search for the time bomb tanker begins where the continental U .S. ends.

I'm driving the Overseas Highway, a 113 -mile -long engineering marvel that runs

over open ocean and connects 44 small tropical islands or keys, the very last

which is the famously laid -back Key West.

This vacation mecca isn't just a hot spot for parrot heads looking for a

cheeseburger in paradise.

It's where I've come to meet my old friend, shark expert, Dr.

Tristan Guttridge.

Dr. Guttridge, I presume. How are you doing, sir?

What's up, man? Good to see you. Great to see you, buddy.

You well? I'm really well. Last time I saw you, we were diving with Captain

Kirk. Yeah, I know. It's surreal.

And today, I've got one hell of an adventure for you.

The Norlindo.

The Norlindo, yes. There were three ships that were torpedoed by the Nazis,

one of them is still missing, the Norlindo. So how are we going to find

ship? We're going to do it by diving on one of the other ships that was sunk

during that attack, the Munger T -Ball. We're going to dive on the Munger T

-Ball. We are. Nearly 150 feet down, and we've got to go 50 miles offshore to do

it. Well, it sounded a lot like you said 50 miles offshore. Yeah.

50 miles. We're going 50 miles off the coast. This is going to provide that key

clue that we'll hopefully find as the Norlindo.

And I'm guessing because you're here, it's going to be sharky. You guessed it.

You are going to be in the water with more sharks than you have ever seen on

of your other dives combined together.

No way. It is so untouched out there. It is remote. It is deep.

It's sharky.

Okay. Should we do it? Yep.

Tristan is anxious to see the Munger T -Ball, or more specifically, the sharks

that live there. It's a prospect that leaves me both excited and the exact

opposite of excited.

We pull away from the dock for our 50 -mile journey out to sea.

Joining us on the mission is Dr. Corey Malcolm, an expert on the shocking

history of how close Hitler's forces came to American shores.

So question number one, what could be more dangerous in the waters off Florida

than sharks?

Two words, Josh.

Nazi submarines.

How bad a problem was this?

It was a terrible problem. At the outset of World War II, the Nazis instituted

what they called Operation Drumbeat.

And they sent their U -boats across the Atlantic to the American coast and

basically shot ships with impunity.

How many ships did they take out?

Through the first part of 1942, they took out over 600 ships. And with that,

,000 to 6 ,000 people were killed.

That's more than twice as many people as Pearl Harbor. Why didn't I learn about

this in school?

Well, you know, honestly, people didn't know about it back then.

These attacks were hushed up by the government at the time to prevent panic.

After the war, they were largely forgotten, making this mission more

than ever.

So let's talk about this particular incident, these three ships that get

out in this attack.

This happens when?

May 4th, 1942.

That's the day the war came to the Gulf of Mexico.

One U -boat in particular, the U -507, penetrated into the Gulf of Mexico right

past Key West.

Right here.

Detailed German logs tell us that at 5 .42 in the afternoon, U -boat 507 fires

torpedo into the stern of the SS Norlindo, which sinks in just three

At 1 .30 a .m. on the 5th, the same sub attacks the Munger T -Ball, which

quickly goes under. The nearby Joseph M. Cudahy sees the attack and radios it

in. And when the Germans intercept the message, they have their final target.

And think the Cudahy just 149 minutes later.

Now, two of the three ships have been found, correct?

Exactly. The Cudahy and the Munga T -Ball. You know, and these ships were

carrying this fuel oil, which supplies them as they're traveling through the

Gulf of Mexico. And this was trapped in their hull.

Fortunately, the National Oceanic and Atmospheric Administration, or NOAA, is

the case.

In 2021, NOAA was able to extract 35 ,000 gallons of leaking oil from the

T -Ball and are planning a similar operation on the Joseph M. Cudahy. The

Norlindo, though, is an even bigger threat to the Gulf. It carries over a

quarter million gallons of oil. And if it were to rupture, the resulting spill

could be catastrophic to marine life, including sharks.

This wreck is a ticking time bomb that needs to be found.

So a simple question, why hasn't it been found? Why can't we find the Norlindo?

Simple question. You would think there's an easy answer. Here you can see a

chart showing the locations of the two known wrecks.

Along with the known locations of the Ball and the Cudahy, the reporting on U

-Boat 507's busy day includes data from the Nazi logs, testimony from survivors,

and finally, records from the rescue ships that arrived later.

Together, they give us an immense search zone of hundreds of square miles to

find the Norlindo.

It's all over the place. It's a lot of confusion.

So now I see the problem.

So we've got a wreck that's a huge threat to the environment and to sharks,

quarter of a million gallons of fuel on board, and a story that demands to be

remembered with a loss of life, right? Absolutely.

You're taking us to the Munger T -Ball to start?

That's where the hunt begins.

All right.

Tristan thinks he knows of some witnesses who've already been to the

and may be able to show us the way.

That's the good news. The bad news is that those witnesses are sharks.

Specifically, bull sharks and tiger sharks, apex predators well over 10 feet

long that weigh more than 1 ,000 pounds.

To conduct the world's most dangerous interview, we take our vessel on the

journey more than 50 miles out into open ocean, where the rest of Tristan's team

is waiting above the wreckage of the Munger T -Ball.

We gather for a safety briefing with Dr. Yanis Papastamatou and dive master

Craig Jeff.

And I take it you're going to be keeping it safe out here?

Yes, sir. And how are we going to do that?

So this is the Munger T -Ball wreck.

It is a serious dive, guys.

the depth on this dive is 140 feet this is an exceedingly remote site okay so

a lot of the animal life a lot of the pelagic life out here will not really

seen humans very often if at all and because they haven't seen them then they

may be slightly more

Inquisitive, they may be slightly more territorial, and they may be slightly

more aggressive.

And will they come in from the sides, from underneath? Like, what's their

profile? They will come from 360 -degree field of attack.

So we have to be exceedingly aware of ourselves, our surroundings, and our

okay, at all times on this dive.

And what's going to keep me from getting ripped to shreds down there, Tristan?

We're going to give you a stick.

A stick? A poker, yeah. Oh, good. That's an official term, a poker? Yeah.

Just another form of protection. If they do get in your personal space, you can

kind of push them off.

Right. Also, the shark's good nature.

Sure, yeah.

Sharks, famous.

Famous for their good nature.

Great. Okay, so I got a stick and a prayer. All right. Should we get into

Yep. Let's see what's down there. Come on.

In addition to watching our backs, we need to watch the clock.

When we reach the wreck at 140 feet, we'll only have a few minutes of bottom

time before the risk of decompression sickness sets in. And at 50 miles

offshore, timely medical attention is not an option.

All right, heading down. Here we go.

Visibility looks good so far. Very clear blue.

As we drop down, we're swarmed by schools of amberjack. After more than 80

on the otherwise featureless bottom of the Gulf, the Munger T -Ball has likely

transformed into an artificial reef, a thriving habitat for prey like these

and the shark predators who feed on them.

Passing 50 feet, visibility's definitely dropping off now.

Yeah, I can't make out the bottom of the wreck.

There's a shark!

Right there!

Right there!

Yeah,

that's a bull shark!

Look at that big bull shark!

It's a top predator in this system.

They're basically a shark that eats other sharks.

Not something to mess with.

Growing up to 12 feet long and weighing in at 1 ,300 pounds, Bull sharks are

notoriously aggressive and unpredictable ambush predators.

They literally have hundreds of inch -long, knife -edged teeth.

But don't worry, I've got a stick.

With a flick of his powerful tail, the

big bull surges forward at 25 miles per hour.

I'm off the Florida Keys diving almost 140 feet down to a wreck called the

Munger T -Ball, a freighter sunk by a Nazi submarine in World War II. Now it's

become an artificial reef that is a hunting ground for some of the Gulf's

predators. That was too close.

It was just curious.

Fortunately, we're not on the menu today.

The farther down we go, the shorter our clock becomes if we want to avoid the

bends. But Tristan believes this wreck is essential to finding the lost ship,

the Norlindo, if, that is, we ever get there.

Is that the bottom?

No, sir, that's a wreck.

Bull sharks thrive in murky water, where they can sneak up on their prey.

Using what's referred to as the bump and bite technique, they grope about for

food in the darkness and latch on with jaws that bite at 1 ,300 pounds per

square inch. The average nail gun uses only 130, so...

Good luck with that.

All right, I'm going inside.

We're over 140 feet deep. We've only got two minutes of time at this depth

before we have to go shallow.

Copy that.

It is so airy in here.

Yeah, 30 people died in here. This is a war grate.

I think it's time to go, guys. We're out of time. We've got to go.

Copy that.

As we make our way topside, we'll have to run the gauntlet again.

More sharks out here. Look at that.

All right, Tristan, I have to say, an amazing experience seeing this wreck.

But the question is, how is this going to lead us to the Norlinda?

It has to do with those sharks.

What do you notice about them?

Well, they're definitely circling us and circling the wreck.

Exactly.

These sharks know where this wreck is, and I can guarantee you they know where

other wrecks are in the vicinity.

So, let me make sure I got this right. You want to use sharks to find a

shipwreck? That's exactly what I want to do.

Okay?

Back on the boat, Tristan tells us how we can use sharks like these as spies to

find the Norlindo and avert an ecological disaster.

So as you said down there, these sharks know where it is.

Yeah, sharks use wrecks. How do they know where these wrecks are? They're not

using Google Maps down there. Like, how do they come back to these wrecks? So we

know that sharks can detect the Earth's geomagnetic field, and we know that a

massive steel hull causes essentially an anomaly in that magnetic field.

Sharks have a remarkable sense receptor organ known as ampullae of Lorenzini.

These small mucus -filled pores are concentrated around a shark's mouth and

snout and give them a sixth sense, the ability to detect electrical and

fields, such as those generated by their prey or an enormous metal shipwreck.

It's likely the shark can detect that massive ship long before they can see

Wow. So they're able to navigate back to it, maybe use it as a waypoint. It's

like having a built -in GPS.

And so you think those sharks can lead us to the Norlindo? We just have to get

them to show us where it is. How do we do that?

We're going to use trackers, and we have two different kinds. The first one is

an active acoustic tracker, and the second is a camera tag. A camera tag?

Yeah, and essentially it's shark cap.

So the shark is going to be showing us where these wrecks are.

Amazing. So how do we get these trackers on the shark?

We need to catch one. We need to catch a shark?

Yeah, we need to catch one.

All right, let's catch a shark.

Sound safe?

I never thought I'd say this on a Shark Week show, but to catch a shark, well,

we're going to need a smaller boat, specifically one that's more

that we can get close enough to place our cameras on the sharks.

Okay, what is this? So this is a cat tag.

What we have here is a video camera. This gives us about 10 hours of footage.

So the sharks are going to be filming for us?

Yes, exactly.

Okay, amazing.

And I'm sure they work cheaper than Brian.

Not much.

The tag clamps to the dorsal fin and records everything the shark sees until

special fastener dissolves in seawater and the device detaches and floats to

surface. So a day from now, this thing pops back up.

And what we have here is a satellite transmitter that's going to send a

to the satellite that gets back to us via email saying this is where the tag

Okay.

To find sharks, the tag near the center of our established search zone. We head

toward a ubiquitous site in these waters.

Shrimp boat.

It's a great place to find sharks. You know, these guys are obviously de

-heading the shrimp.

So the sharks follow and eat the scraps, basically. This is the dinner bell.

Exactly. I'll throw a few...

Little fishes and we'll see what they do. Okay.

Throw some bait in.

If you've ever wondered how long it would take a hungry shark to smell you

the water, stand by.

What is that?

Yeah, something's coming in now. Look at this. Wow.

We got sharks everywhere.

The entire surface just became alive.

These are silky. These are silky sharks, yeah. There must be 20 of them just

boiling up at the surface here. These juvenile silky sharks can ultimately

as large as 8 feet.

Named for their silky smooth skin, these sharks still have flesh -ripping, razor

-sharp teeth.

Fun fact, they're the most abundant shark species on Earth.

And it looks like all of them showed up for dinner.

I assume these sharks are a little too small for us to be putting a camera tag

on. Yeah, these are way too small. These silkies have really small dorsal fins.

They're not going to work. So what we want is one of these big bull sharks.

there should be some bulls in this community here. You can see a bull down

right at the base. Ah, look at that! There is one here. Big boy! Two of them!

Throwing small pieces of fish got us small sharks.

But to get the attention of one of these bulls, we need to...

scale up our ambition.

All right, well, we got some bait.

Perfect. And we've got a big bull right underneath us.

To keep the bull from taking our shark cootery board to go, the bait is

to a carbon steel hook and two buoys called polyballs, which will let us know

where he goes as well as tire him out. Here we go. We got a bull coming in.

Oh, he's got it. He's on it.

Here we go. He's off.

You can't dive not with two barrels on them, you can't.

Charles?

Oh, boy.

I think he's back for his noon feeding.

I'll do the whole movie. I don't care.

I'll do the whole thing, end to end.

It takes the entire team to wrangle this shark.

A powerful bull can rip the line right through your hand.

Or worse, pull you under.

Coming up.

But when we try to bring the bull in... Spit it out?

Shoot through, spit it out.

Bigger hook in half. Look at that.

He literally bit this hook in half.

Pound for pound, the bull has the strongest bite of any shark.

Their powerful jaws can even crush bone, or in this case, a carbon steel hook

rated to hold 4 ,000 pounds.

That shouldn't happen. I've never had one bite the end off like that. It's

ridiculous. That bull shark went through that like butter.

You got more of these?

I've got more of those. Let's catch another one. Let's do it. Come on.

We send out the bait.

It's going its way.

And in a matter of moments, an even bigger bull is on our line.

Just let it go.

And he's running. Here we go.

Diving. Definitely on. Both buoys are down.

He's going this way.

I see him down there.

I think we can start pulling in this shark.

Here we go.

That's a big shark.

But when you're working with a creature that's more than 10 feet long and

packing 600 pounds of pure muscle, the advantage goes to the shark.

Okay. Here we go.

Just keep him on the... Overboard right there.

Ooh, the other one's with him.

Grab the dorsal.

I got it.

Josh, watch out.

Got it?

Careful. Someone got my hand!

In the warm waters of the Gulf of Mexico, I'm helping Tristan Guttridge

camera to a massive bull shark.

Why? Well, right now that's a question I'm asking myself.

Here we go. Try again.

I'm on the dorsal fin.

I'm good here. I got the dorsal.

To be this close, to be holding this creature against the boat.

It's absolutely awe -inspiring. It is just huge, and it is just pure muscle.

It's unbelievable.

We're hoping to use the shark as a cameraman to locate the wreck of the SS

Norlindo, which was sunk by a Nazi U -boat somewhere nearby in 1942.

Okay,

pack is on. Here we go.

The camera is attached, but we're still at risk.

Yanis turns the shark over and, with a few quick movements, puts it into a

known as tonic immobility, basically a trance where, for a brief, blissful

moment, she won't bite at our hands as we release her. Then we're safe to let

her go.

Ready?

Go! Woo!

All right.

Norlindo, here we come.

All right, that shark is off to make its first motion picture.

Sharky for Daisy.

Marty, Shark Daisy.

Marty for Sharky.

Steven Sharksburg. Quentin Sharkantino. It doesn't matter. I'll think of it

later. The point is that shark's got a camera.

Remember, that footage belongs to Discovery.

Just don't post that footage on OnlyFans.

All right, we got one down.

Let's do it all over again.

For the next few hours, we catch and place camera tags on four more sharks.

more to go.

Building a first -of -its -kind camera crew to locate the wreck of the

He's got it. He took it.

Yeah,

go find the wreck.

Okay, we got it. We got it.

The bulls are out filming with the camera tag, but we won't get to see the

results for a day.

To actively track the shark population, though, Tristan wants to use acoustic

tags. With acoustic tags, we can follow the sharks in real time as they move

from wreck to wreck.

But this requires us to tag sharks in the water and away from a feeding

So Tristan directs us to what he refers to as a perfect wreck for sharks. It's

not exactly what I'm expecting.

Is that it?

That's where we're headed.

That's a wreck?

In a sense.

What is this thing?

Decommissioned radar tower.

Once used to relay radio signals, this tower's legs extend 100 feet down to the

ocean floor.

And unlike a shipwreck, this vertical reef created a shark habitat close to

surface where we can tag them.

However, if anything goes wrong out here, we're utterly on our own.

Nobody comes out here to dive. We're in the middle of nowhere.

These are going to be really wild animals.

Stick close together, stay close to the structure, don't go too deep.

Should we dive?

Yeah. Let's see what's down there.

We gear up and Tristan attaches the acoustic tag to the end of a long spear

which he'll use to place it onto a passing shark's dorsal fin.

As for me...

Don't worry. I still have my pokey stick.

Here we go.

Visibility looks great.

Yeah, we must have at least 30, 40 feet. Then it gets murky.

Look at this structure. This thing is huge.

Yeah, it's like an underwater spider.

It's really eerie to see those legs just going down into the murk.

This structure is abandoned, but look at it. It's alive.

There's a bull shark. Look at that.

And another.

Whoa.

I cannot believe how many sharks are all around us. I got to say, Tristan, I

never get used to this.

And I love this feeling.

knowing that they're around there.

And I'm guessing the Norlindo, wherever she is, is also covered in life.

You can see why the sharks are hanging out here. Look at the food supply.

We just got to keep ourselves off the menu, guys.

So what's our strategy here to tag one of these?

They're kind of on the periphery, but they seem to be coming in and making

passes near the structure.

I'm going to hide next to this structure and then pounce and take a tag shot.

Copy that. I'll watch your back.

While Yanis and I watch his six, Tristan moves into position with the tag.

But we're so focused on tagging a bull that we almost miss the arrival of an

even bigger and badder species coming right for us.

Tristan, behind you! Tiger shark!

That's a tiger. It's huge.

While attempting to place a tracking tag on a bull shark circling a

decommissioned radio tower in the Florida Keys, Tristan, Yanis, and I are

surprised by an even deadlier predator.

Whoa, massive tiger shark.

I lost her. Where did she go?

Tiger sharks are bigger than bulls and can grow up to 16 feet long.

Known for their powerful serrated teeth, which can slice through the toughest of

prey, they've been nicknamed the garbage can of the sea because they can and

will eat anything, including people.

I do not have eyes on her. She disappeared into that murky water below.

I'm going to do another attempt. I've got to get this tag out.

With dozens of bulls and a massive tiger shark circling just a few feet below

us, Tristan leaves the safety of the tower.

Okay, I'm taking my shark.

Here we go.

I got it! Nice.

Beauty! Nice work, Tristan.

Beautiful female bull shark.

All right, tag is in.

Mission accomplished.

Let's hope she's coming straight to the Nerlindo.

Let's go back to the boat. Here we go.

Yep, heading back.

We quickly jump back aboard the boat so we can send one of the research vessels

off to chase and track the acoustic -tagged shark.

The next morning, Yanis gets an important email.

The first of our camera tags has surfaced and sent us GPS coordinates.

Time to see if our cinematographers have found our missing tanker.

We've got the coordinates, so we know where to head out. Okay, Johnny, we've

some coordinates for you. Okay, it's north, 24 degrees, 55 .669.

West, 82 degrees, 15 .996.

How far is that from here?

Eight and a half miles to the northwest of here. Okay, let's rock and roll. Come

on, let's find it.

We race off to find the first camera tag.

As we close in on the coordinates, we flow down to home in on the tiny device

floating in the vast ocean.

All right, how are we going to find this thing?

So we've got to try and pick up the radio transmitter. We can do it with

antenna that we have here.

You mean old TV antenna?

It's essentially the same thing. This will detect that radio signal, and this

will turn it into an audible ping that we can hear. So we'll turn it on.

If this thing works, I'm going to eat my hat. This is set to a specific

frequency all that time.

Okay, let's do it.

Keep your eyes peeled. Here we go.

We follow the pings.

Straight on, Johnny. Nice and slow.

Carefully scanning the water for a red speck.

You think we're close?

Yeah, we're getting really close.

We should be able to see it by now.

Everybody keep your eyes open, all sides of the boat.

It's got to be right here.

Johnny, let's flow all the way down.

I see it. You got it? Right there, right there. Wait, where, where, where?

Oh, there it is. There it is. Just up starboard. Just up starboard. That's our

tag right there. Dude, nice work.

Tony, we find it.

Yes.

Woo.

Unbelievable. Nice one.

All right, camera number two, let's find it.

We spend the better part of a day getting emails and chasing cameras.

There you go, man.

All right, tag number two.

Oh, there it is. Yeah, there it is. Off the bow, off the bow.

You see it? Yeah.

Got it.

Lucky number three.

That's it?

There it is, there it is. That's got to be it, right?

Thankfully, the sea is calm.

Otherwise, we could be chasing these all the way to Cuba.

With all of our footage in hand, we catch up with the big boat to see what

got from both the camera tags and the acoustically tagged shark from

All right, so let's talk data. So we have a track here, and we're plotting a

point every 30 minutes where that shark is. Okay. And here's what it looks like.

And you can see that the shark is kind of following a contour.

Yeah. Essentially not really making any moves left or right. It's kind of going

on a fairly straight path.

Yeah. And then it starts to mill around a certain area. Look at that. It starts

to actually circle this.

Right. So it's kind of like maybe it found a reef habitat that it's moving

around and hunting.

Or maybe it found a wreck. Or it could have found a wreck.

Just like the way the sharks were circling around the Munger T -Ball.

we have no idea what's in this.

No, with the acoustic tracker, we know where the shark is, but we don't know

what it's seeing.

All right, so that gives us a place to look.

Right. Now what about the camera tags?

We have camera footage.

Shot by sharks. Yep. Your shark camera crew works perfectly.

Amazing. Let's see it.

First look at self -shot shark footage.

We're seeing what these animals do when we're not around.

Okay, so we've got a shark here. Look at that.

One of our sharks.

is going up to several other ball sharks.

So there actually, you know, clearly is sort of a group of them hanging around.

Oh, look at that.

Wow.

So much action. I can't believe how many of them are just hanging out together.

Now to the million -dollar question, the hunt for the Norlindo. Did you find

anything in this footage that may help us with that?

So there is something I want you to see.

There is?

Yeah. Come on. Okay.

What did you find? Look in here. Okay. It's murky.

Okay. Wait for it. It's coming up.

Okay.

Oh, right there.

That is wreckage. That is definitely wreckage. Straight edge.

The question now is, is that a piece of debris that fell off a ship, or is that

a wreck?

The only way we're going to find that out is to go and take a look ourselves.

All right.

Let's dive, yeah?

Let's do it. Right now. Come on. Let's do it. Go.

We take off for the target. Not only did one of the camera tags capture

something that looks man -made, but it's in the same vicinity the acoustically

tagged shark was circling, an area well within our search zone for the Norlindo.

We may be zeroing in on the lost tanker.

Let's see what's down there.

We splash down and start heading for the bottom, our eyes wide open.

Be careful because we know that there's sharks around.

They brought us here.

Absolutely. I got my eyes open.

We don't have to wait long. The local welcome wagon quickly swims up to greet

us.

We've got sharks.

One o 'clock.

Four o 'clock.

All o 'clock.

Don't panic. Just keep it in front of you.

But it's the murk below that we're most worried about.

where bull sharks may be lurking to attack, and we wouldn't know until it

too late.

Need an example?

Got a big bull coming up here.

Man, that's a beast.

Swimming back down, though.

I don't see it anymore.

He's circling around.

Look out!

Whoa!

Whoa! Close, close, close.

Big bull shark coming in.

We're exploring a dive target more than 50 miles from Key West, Florida.

Everyone stay together. We just saw three or four bull sharks on the

Hopefully these bulls have led us to the wreck of the theme freighter Norlindo,

a missing tanker torpedoed by the Nazis in 1942 that's still carrying up to a

quarter million gallons of oil in her hold.

Pulling up on 50 feet. We should be near the bottom.

I can't see anything. I don't know what. Oh, wait, there it is. There's the

bottom right there. You see it?

Yeah, it's just sand here.

There must be something down here. Those sharks must have been circling

something.

With a watchful eye on the sharks circling overhead, we fan out and scour

bottom for traces of a wreck.

But there's a shadow up here.

There's something in front of us. Oh, wow.

The wreck is hundreds of feet long, which fits.

The Norlindo was a little over 250.

As we work our way around the wreck, we find a gaping hole on the starboard side

of the vessel.

Guys, I found a way in.

But was this damage caused by a Nazi torpedo or natural decay?

I'm sure this is World War II.

I don't want to run into a shark down in these close quarters or find whatever's

left of Ben Gardner, so I leave the wreck.

The side of the hull looks about right, but we should be seeing a bridge and a

smokestack somewhere.

Yeah, I can't see anything like that.

This wreck's been down here a while, but it's just too box -shaped to be the

Orlando, in my opinion.

I agree. This thing doesn't look like an old steamer. It looks more like a barge

vessel of some kind. Yeah, I think it's a barge.

We've still got a real mystery on our hands here. I have no idea what this

is, but I think that's a Norlindo.

Whatever this wreck once was, it now belongs to the sharks.

Whoa, watch your two.

Big bull shark.

And as uninvited guests...

It's now time for us to make our way to the surface.

Unbelievable. Absolutely incredible.

Oh, what a wreck. The huge steel ship down there, not the Norlindo, really

squared off some sort of industrial barge, I think. Yeah, it looks like a

And I think the real headline is here, this worked.

These sharks led us to a wreck.

Who needs sonar when you've got sharks? That's right.

So we've got another wreck today to add to the charts here.

And in terms of the Norlindo, we keep looking. At some point, a shark's going

take us right through that. That's right. More work to be done, and we're

case. And the sharks are on the case. They are. All right. Awesome work, guys.

Amazing job.

Ah, incredible.

It's a huge wreck down there.

So cool.

We tend to think of World War II as something that happened in Europe and on

-flung Pacific islands.

But a forgotten home front lies just off the coast of Florida, where Nazi

submarines sank hundreds of ships, too quietly claiming 6 ,000 American lives.

Eighty years later, the sea has transformed death into life, as these

have bloomed into shark habitats.

vital hunting and breeding grounds that are irreplaceable.

But the rusting hulk of the Norlindo, with a quarter million gallons of fuel

still in its hull, poses a dire threat to the species that call it home.

And until it's found, these fragile shark populations are at risk of

the final victims of the forgotten front from World War II in the Gulf of

Mexico.