NARRATOR: The beaches and cliffs of Normandy.
In June 1944, the most important place on the planet.
DR DELGADO: It's the greatest battlefield in human history.
Full of incredible stories.
NARRATOR: But some of D-Day's greatest stories remain untold,
because vital evidence is hidden beneath the waves.
Imagine if we could empty the oceans.
Letting the water drain away to reveal the secrets of the sea floor.
Now we can.
Using accurate data.
And astonishing technology.
To bring light once again to a lost world.
What shocking weapon blew a key British warship into fragments?
Can this shattered landing craft explain why Omaha was the bloodiest beach of them all?
HENDLEY: Unloading had to be stopped, because the living couldn't climb over the dead.
NARRATOR: And why did the power of the sea mean life or death on Utah beach?
DR DELGADO: The seas were still churned up and as the man next to you goes down,
it's the luck of the draw.
NARRATOR: After more than a year of meticulous planning,
7,000 ships and a quarter of a million men are ready.
The Allied invasion of Nazi occupied Europe is about to begin.
NICHOLAS: The scale of D-Day is absolutely epic.
It's the most extraordinary thing that's ever been undertaken in history.
NARRATOR: For years, archaeologists have studied the battle on land.
But now, they're looking somewhere else.
Marine archaeologists working with the French underwater unit, DRASSM,
are scanning 50 miles of coast using the latest 3D technology
ANDY: This is the largest continuous underwater mapping
projects ever done for this particular area.
NARRATOR: They've already discovered 300 military relics.
Many unknown to historians.
ARCHAEOLOGIST: That is really odd.
It's really hard to tell what we're looking at.
NARRATOR: Scanned in forensic detail, this deep-sea treasure trove is transforming
our understanding of the invasion.
NICHOLAS: It's all still there in a way that actually it isn't on land.
And we found some tremendously exciting things.
NARRATOR: Now for the first time, we can use this data to unlock the secrets of D-Day.
By draining away the murky waters of the Normandy coast,
to reveal exactly what happened here.
As the seas begin to empty, they uncover just some of the hundreds of wrecks.
Each with a story to tell.
Target number one, an allied destroyer.
Sunk before the landings even begin.
Her fate is one of D-Day's greatest mysteries.
1,200 allied warships approach the Normandy coast.
At 5:23 in the morning, they open fire.
Catching the enemy unprepared and off-guard.
PROF GROVE: One can imagine the feelings of many of the Germans.
It must have been sheer terror to have seen this huge fleet.
NARRATOR: Fire rains down on the five beaches the allies have marked for invasion,
Utah, Omaha, Gold, Juno, and Sword.
A Norwegian destroyer called the Svenner is on the eastern flank.
A crew of 219 are preparing to join the bombardment of the beaches.
When suddenly
a massive explosion and she's gone.
How is this Svenner destroyed while surrounded
by over a thousand heavily armed warships?
Data from the survey contains tantalizing details.
Combining them with the latest computer visualization techniques
means we can empty the Normandy coast, and go looking for clues.
As the water begins to drain away.
A sight lost for 75 years.
Hundreds of tonnes of twisted and ruined metal.
Shocking evidence of a huge explosion.
The bow and stern are in one piece.
But the midsection is shattered.
What could have caused so much damage?
It can't be a shell.
The Svenner is beyond the range of German artillery.
And it can't be a bomb.
The allies completely dominate the air throughout D-Day.
But returning to the scan data, the survey team has a theory.
SAUVAGE: You can see that the ship was violently broken into,
because two parts have sunk in two different orientations.
So that really is the impact of a torpedo explosion.
NARRATOR: If it was a torpedo, does that mean a hidden u-boat
managed to penetrate Allied defenses?
To find the answer, the team must dig deeper
into the secret history of D-Day itself.
Historian Nick Hewitt visits Suffolk House,
headquarters of D-Day commander, Dwight Eisenhower.
NICHOLAS: This room was the nerve centre of a huge operation.
It was planned all over the UK, all over the world, actually,
and it was two years in the making,
and this map is the very map used by Eisenhower and his senior commanders
to make it all happen.
The key elements that could be controlled were when it was going to happen
and precisely where it was going to happen.
NARRATOR: But the only way this plan could work is if the Germans never learn of it.
To divert attention the Allies leak fake plans.
PROF GROVE: We had to keep the Germans guessing, which we did,
by an enormously successful deception plan,
which meant the Germans didn't know, were we going to land in Norway perhaps?
Were we going to land just across the channel?
That was a vital part of the operation.
NARRATOR: Hitler's defense against invasion is the Atlantic wall.
A vast network of bunkers, pillboxes and artillery positions lining the coast
from Spain to Norway.
He believes the allies will attack somewhere along the coast of the English Channel.
And orders Field Marshall Erwin Rommel to stop them.
Influenced by the Allied deception plan,
Rommel believes his enemy will need a deep-water port.
So concentrates his forces and heavy artillery at Calais, Cherbourg, and Le Havre.
So when the invasion fleet targets the beaches of Normandy along the bay of the Seine,
the most powerful German defenses are in the wrong place.
And there is not a single U-boat nearby.
So if the Svenner was blown apart by a torpedo, it can't have come from a U-boat.
The survey team dig deeper and uncover another suspect.
NICHOLAS: By June 1944, the German navy is almost finished as a fighting force,
but they do have the number of small warships, operated by actually incredibly
well-trained and courageous crews.
NARRATOR: Small warships like these, torpedo boats.
They pack a real punch.
With six torpedo tubes and two anti-aircraft guns,
maneuverable and sleek
they can reach a top speed of 35 knots.
Perfect for a hit and run.
And there's a flotilla of them in Le Havre.
Just 20 miles away from the D-Day fleet.
Now, using all their research, and details from the drained wreck of the warship,
the team can reconstruct exactly what happened to the Svenner.
Just before dawn, the fifth torpedo boat flotilla is ordered to attack.
A force of just four boats will challenge a thousand Allied warships.
Out of the blue, the T-boats approach the invasion fleet.
The Allies have laid a dense smoke screen.
The T-boat crews use it to their advantage.
They get close enough to fire 18 torpedoes.
Each packed with 600 pounds of explosive, enough to cripple the biggest warship.
But now, the smokescreen helps the Allies.
The T-boats are firing blind.
17 torpedoes miss their mark.
Leaving just one that runs straight into the Svenner.
186 crewmen swim to safety, but 33 go down with the ship.
The haunting remains of the vessel stand as brutal testimony
to the deadly power of a German T-1 torpedo.
But the Nazis are so unprepared,
that this is their only success at sea throughout D-day.
PROF GROVE: The fact that the Germans are able to inflict only this single loss
demonstrates that the defenses that had been planned
for the landings were very, very successful.
It was now up to the army alone and the army would have a difficult job.
NARRATOR: The battle for the beaches is about to begin.
All of them packed with defenses.
Pillboxes, barbed wire, machine gun posts.
As the waters along the Normandy coastline continue to recede,
they reveal strange objects on the sea floor.
What can they tell us of Allied plans to confront the terrifying challenge ahead?
The naval guns fall silent.
More than 100,000 highly trained troops are ready to storm fortress Europe.
23,000 Americans approach the most Western of the beaches.
Codename Utah.
But their plan immediately unravels.
Strong currents push them more than a mile from their designated landing zone.
And yet, for many, this turns into a stroke of luck.
Led by Brigadier General Theodore Roosevelt, son of the former President,
they land in an area between two German strong points, an enemy blind spot.
DR DELGADO: When they come ashore, they realize they're in the wrong spot,
but it turns out to be the right spot, because there's less Germans there.
And so Theodore Roosevelt Jr in command, simply stops,
plants his flag and says, the war starts here.
NARRATOR: Roosevelt's men outflank the German positions.
And soon control the beach head.
But a mile and half off shore, the survey team discovers something surprising.
Strange shapes on the sea bed.
It looks like some Allied units never reached Utah beach .
ANDY: Looks like three different vehicles of some sort,
like potentially an upside-down tank here.
And then this vehicle's a bit more difficult to determine
what it is and so we'll try to take a close look at that.
NARRATOR: Divers go to investigate
and find the wrecks heavily encrusted.
They spot what could be tank tracks.
And a gun barrel.
But visibility is too poor to identify them.
There is one way to see clearly.
Combine visual clues with the teams 3D scan data and drain millions of gallons
of sea water away.
As the waves recede, they gradually reveal a cluster of military vehicles.
But the puzzle only deepens.
They have gun barrels, and a turret set to one side.
They've got tracks, heavy armor.
They look like tanks.
But this isn't a tank gun.
It's more like the cannon of field artillery.
So what are they?
The team examines specialized Allied weapons designed
for the unique challenge of this terrain.
And focus on close support artillery.
In World War Two, artillery is normally pulled by men, vehicles or horses,
but in sand and water, this won't work.
So, to support the infantry on the beaches the Allies deploy these.
M7 Priest Guns.
Artillery that transports itself.
105mm Howizer mounted on the chassis of an M4 Sherman tank.
A tank fires in a flat trajectory, so the target must be in its line of sight,
but a howitzer fires in an arc to lob shells up and over obstacles.
Perfect for enemy positions high above the Normandy beaches.
More research reveals that the Americans have 30 Priest guns ready to land on Utah beach,
carried on amphibious landing craft.
Accounts from the day suggest only 27 make it to shore.
Archaeologist, James Delgado, thinks that these could be the missing three,
but they're nowhere near their landing craft, which means whatever happened
was so violent, it threw the Priest guns clear.
What Nazi weapon was powerful enough to do that?
He has a theory.
DR DELGADO: This entire 50 mile long section of the coastline had been fortified.
Rommel had anticipated scattering some 50 million mines,
he was only able to deploy 20 million mines, but just the same, if you consider that,
it just boggles the mind.
NARRATOR: The night before D-Day, around 300 Allied minesweepers
carefully clear channels to each of the five landing zones.
The invading fleet should have a clear run to the beaches.
So what happened to the three Priest guns?
The survey team spots something else.
Plotting the precise co-ordinates of the guns, places them well off course.
Their landing craft has strayed out of the clear channels
and drifted into an uncleared minefield.
The same shifting currents that so helped Roosevelt's infantry,
push it into deadly waters.
The huge power of Rommel's sea mines
explains why the priest guns were thrown
far from their landing craft.
The bodies of the seven men crew may still be inside each of these vehicles.
A haunting reminder of the human cost of D-Day.
At Utah, this is one of the few Allied set-backs.
Roosevelt's men take the beach head with just 200 casualties,
but 15 miles along the coast other young American soldiers
are struggling in the terrifying bloodbath of Omaha beach.
Ten times more men die here than at Utah.
But why?
The survey team think they've found a clue amid a twisted mass of metal on the sea floor.
As the once blood-stained waters of Omaha beach drain away,
can this astonishing new discovery shed light
on D-Day's deadliest battlefield?
After two hours of fighting on Omaha beach the Allied plan is falling apart.
Troops are pinned to the shore.
2,000 dead and injured soldiers litter these sands.
It's the bloodiest engagement of D-Day, but why?
The survey team is eight miles off shore, looking for clues on the seabed.
When their scanner picks up an unusual outline.
CHRISTOPHER: We do have a definite flat bottom boat
with a substantial amount of damage in one corner
and the front is missing entirely.
NARRATOR: Divers take a closer look.
Visibility is poor, just six or seven feet
But, it's immediately clear that whatever it is, it's taken a hell of a beating.
There are bullet holes everywhere and that's not all.
NARRATOR: Mangled beyond recognition, the team has no idea what it is.
But the multi-beam scanner has captured every detail.
Using that data, we can drain away the waters of Omaha beach,
to reveal a twisted mass of metal.
It's lying upside down, making it even harder to identify.
But, by using the scan data, we can raise and rotate the wreck,
exposing the very topside for the first time in 75 years.
Now, the team think they know what it is.
An LCI, landing craft infantry, one of the workhorses of D-Day.
They compare their data with U.S. navy records
and make a huge breakthrough.
They believe it is LCI 85.
Can it help us understand just why Omaha beach was D-Day's bloodiest?
It's clearly been at the heart of the battle.
Its bow is blown clean off.
It's covered in bullet holes and shrapnel damage from exploding shells.
Ragged and twisted metal here suggests a devastating explosion.
The damage on LCI 85 reveals the power of German weapons
unleashed upon the Americans as they tried to land.
And there is other evidence too.
The team unearth first hand accounts from men who served on LCI85 that day,
including commanding officer Coit Hendley and Lieutenant Arthur Farrar
Now it's possible to convey what happened in terrifying detail.
Allied troops have been landing for two hours.
But Omaha with its high cliffs is the most heavily defended of all the beaches,
and the Americans are pinned down under heavy fire.
LCI 85 approaches the beach with much needed reinforcements.
Lieutenant Farrar must get the 188 troops on board quickly to shore.
His problems start immediately
ARTHUR: The path 50 yards wide was supposed to be cleared
through the underwater obstacles.
We found it near to 10 yards wide and only partially cleared.
NARRATOR: Blocked by an uncleared mine field,
LCI 85 is pounded by shell after shell, fired from the cliffs.
Under a hail of bullets, the commanding officer tries another route.
ARTHUR: We then tried ramming through the obstacles about
200 yards to the right of our assigned place.
NARRATOR: But, as the LCI grounds, it immediately hits a mine.
It starts to sink, but is close enough to shore for 50 men
to scramble towards the beach.
Then another direct hit from a German shell smashes the landing ramps to pieces.
HENDLEY: We could hear the scream of men through the voice tube,
unloading had to be stopped,
because the living could not climb over the dead.
The deck was so slick with blood and cluttered with bits of flesh and dead,
and mutilated men that it was difficult to move from one part of the ship to another.
NARRATOR: And we don't only have the words of eye witnesses.
Extraordinarily, the team discover color footage too.
The courage and carnage on board LCI 85 is captured by a combat camera team
at the height of the battle.
Here, filming the bodies of the dead, and the injured awaiting rescue.
Shot in the leg, Lieutenant Farrar is one of the wounded.
He watches as his remaining troops board another landing craft and attempt once more
to reach their comrades on the beach.
Astonishingly, 93 of them make it.
But LCI 85 is now barely afloat.
Her crew take the decision to scuttle her, by setting off an explosive charge.
The drained wreck of LCI 85 is testimony to the horror of Omaha beach.
The Allied bombardment has failed to take out any of over 40 enemy strong points,
leaving men who try to land here facing shell fire.
Machine guns.
And unswept mines.
Finally, for those who do reach the beach, a new kind of hell awaits.
DR DELGADO: In this beach, men are being mowed down with erupting fire,
with shrapnel flying everywhere.
And men are hunkered down and they're waiting, as engineers try to advance to clear mines
and to take out pillboxes, and it takes some time.
And as that happens, the casualties mount,
making this the bloodiest beach on D-Day.
NARRATOR: Securing Omaha costs over 2,400 American lives.
It's the last of the five beaches to fall.
But the Allies cannot rest.
The must now prepare for the inevitable counter attack.
And that means landing thousands of tons of supplies every day.
With no ports, it's a huge challenge.
The survey team is to the east of Omaha, near to Juno beach.
They detect a new wreck, it's huge and it's in pieces.
What can this shattered warship reveal about a desperate Nazi attempt
to stop the Allies in their tracks?
D-Day plus two.
Over 4,000 Allied troops have died to claim the five beaches, but 130,000 are now on shore.
Another 700,000 are ready to land, along with vast quantities of vehicles,
fuel, ammunition and food.
The battle to resupply the bridgehead has begun.
These vital operations are coordinated from specially adapted warships.
For Juno beach, that ship is HMS Lawford.
Equipped with powerful anti-aircraft guns,
and state of the art submarine hunting technology,
she's one of the most up-to-date ships in the Royal Navy.
PROF GROVE: Considerable modifications made to the superstructure,
she was given a large number of radars and communications equipment,
and she was converted into a very significant command ship.
NARRATOR: In the quiet of the morning, HMS Lawford is already hard at work.
The Allies have secured the coast, the enemy is nowhere in sight.
When suddenly, there's a huge explosion.
And a short time later, HMS Lawford is gone.
The Allies are dumb-struck.
The mystery of the Lawford makes her a priority for the survey team.
When she's located, in 70 feet of water,
divers go in,
looking for clues.
James Delgado runs the dive from the bridge.
DR DELGADO: Dan, Dan, this is topside. Do you read us?
DR DELGADO: And you're able to look inside?
NARRATOR: The divers inch their way through the Lawford's stern.
NARRATOR: Exploring evidence untouched for 75 years.
NARRATOR: They discover an unusual clue.
A set of tubes, or narrow gun barrels, their purpose is another mystery.
It's time to look more closely.
Combining the dive team's findings with the latest multi-beam scan data,
we can start to remove the waters off Juno beach.
As the bay of the Seine slowly empties.
It reveals a shocking crime scene.
The Lawford is in three pieces.
The bow and the stern are over 300 feet apart.
A sea mine is unlikely to cause this type of shattering damage.
So what could have?
At the bow, the set of tubes found by the divers is revealed to be a hedgehog.
A weapon system that can fire 24 mortars at a time, over attacking U-boats.
But the hedgehog is not loaded, it could be that the mortars were fired too late
to avert a sneak torpedo attack.
Or that is was never loaded in the first place.
But a torpedo seems unlikely.
The Allies had blocked all U-boats from the area since D-Day.
And the damage on the wreck suggests something more powerful than even
the biggest German torpedo
It's the kind of damage expected from a thousand pound bomb.
A deadly payload delivered by the Luftwaffe.
And yet, the Allies still have complete air cover.
Back at the stern, there's another clue.
The boxes the dive team thought were batteries are actually full of unused ammunition.
The Lawford hasn't even fired her guns.
So whatever got her was a total surprise.
And was not spotted by the ship's advanced early warning systems.
The team believe that leaves only one suspect.
A hi-tech Nazi wonder weapon.
Developed in secret by German scientists for the past four years.
A Henschel Hs 293 glide bomb.
NICHOLAS: It's what in modern parlance is called a stand-off bomb.
They basically enable German pilots to launch their weapon out of range of anti-aircraft
gun fire, away from marauding fighters,
and they can launch these bombs and guide them
into place through radio control.
NARRATOR: Operated by remote control, the HS293 guided missile
is almost impossible to stop.
And accurate enough to home in on its target's weakest spot.
(explosion)
Aimed directly at the engine room, the 1,100 pound bomb
causes a massive internal explosion.
Killing 37 men instantly.
HMS Lawford never stood a chance.
With the mystery solved, it's clear that even in the days after D-Day,
the fight for the Normandy coast is far from over.
And even the most powerful Allied warships remain at risk.
Like this one.
One of the titans of the Allied invasion force, close to Omaha beach.
What sent this giant to the bottom of the sea?
The Normandy coast is under Allied control.
But driving Hitler's armies out of Europe will require millions of men
and vast amounts of supplies.
Delivered by these, LSTs or Landing Ship Tanks,
the Goliaths of the invasion force,
each capable of carrying more than 60 military vehicles.
75 years later, the survey team is searching for evidence of that supply operation.
Six miles off Omaha, their scanner picks up the large wreck of an LST.
Cross-referencing its location with navy records gives it a number, 496.
Now, they want to find out what happened to it.
Using the team's precise 3D data, we can drain away the water.
To reveal the smashed remains of a D-Day heavyweight.
It's an astonishing scene.
Packed with clues.
The bow is obliterated.
Scattered all around, the tanks and trucks it was carrying towards Omaha beach.
The whole sight is a catastrophic mass of twisted metal.
The ship is lying upside down.
A 40 foot hole ripped through the hull.
Likely too large for a torpedo and too low for a glide bomb.
Piecing together the evidence at the wreck site,
Nick Hewitt thinks he knows what happened,
an encounter with an ingenious, but deadly weapon, called an oyster mine.
NICHOLAS: So this is a sea mine that responds to changes
in water pressure caused by passing ship and that is
a weapon for which there is absolutely no antidote.
NARRATOR: In a nighttime stealth attack, fast German vessels
called E-boats drop oyster mines in Allied shipping lanes.
Each one is packed with around 1,500 pounds of explosive.
They are set to detonate, only when ships heavier than minesweepers pass overhead,
making them near impossible to detect.
LST 496, carrying over 60 tanks and trucks is heading straight into danger.
As it approaches Omaha beach, the downward pressure of the hull triggers a mine.
A huge explosion blows a hole in midships on the port side.
The power of the blast is so great, it detonates a second oyster mine.
This time, the explosion rips right through her hull.
In just 40 minutes,
LST496 sinks to the sea floor, taking her war fighting cargo with her.
And more American soldiers and sailors join the list of those who sacrificed
their lives to liberate Europe.
DR DELGADO: Here in the American cemetery overlooking Omaha beach,
in the midst of these graves of more than 9,000 men,
75 years on, if the question were to be asked,
was this sacrifice worth it?
The answer would still be a resounding yes.
Because of what they did, the new world arose,
embodying the ideals for which these men fought and died.
(music)
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