Boy: Hey you!
Diver: How many of you?
Narrator: For almost three weeks,
13 young lives hang in the balance.
Jason: We didn't want them to die and we didn't want to die ourselves.
Narrator: Then, against all the odds.
Reporter (over tv): Mission impossible has become mission incredible!
Narrator: One of the greatest rescues of all time.
Pasakorn: It was like a miracle
Narrator: But questions remain.
How did the boys get trapped?
Why was it so hard to rescue them?
Martyn: The prospect of a diving rescue was
Hideous from the outset.
Narrator: And how was it done?
Chris: Nothing like this has ever happened before.
Jason: Everything was experimental.
Narrator: Now, with unprecedented access,
A team of cavers conducts the first ever 3d scan of
Tham luang, to uncover the answers.
Reconstructing the cave in perfect detail.
Roo: We're going to be able to actually show what that
Passage was really like.
Narrator: Transforming our understanding of the
Thai cave rescue.
Vern: If two of them came out alive that would've
Been a good result.
(theme music plays).
Narrator: 13 young survivors and a moment few thought possible.
Boy: Thank you so much.
(speaking in native language).
Boy: Thank you.
Narrator: Leaving the hospital, after an astonishing escape
And a terrifying ordeal.
25 days earlier, a school soccer team, the wild boars,
Enjoyed a day trip to tham luang cave.
This is the last picture taken before they entered,
As night fell they were still inside.
Reporter (over tv): A dozen member of a youth football
Team and their coach are missing.
Reporter (over tv): Thought to be trapped in an underground cave.
Narongsak: Every minute is important.
Narrator: It would take 18 days,
17 cave divers,
200 air cylinders, a mile of rope,
10,000 volunteers from over 20 countries,
And one death,
Before they could bring the wild boars out of the cave.
Pasakorn: The whole world had their eyes upon us
To see what we would do.
Reporter (over tv): We begin tonight in thailand with the
Life and death drama that's captivating the world.
Narrator: The drama played out deep beneath the
Doi nang non mountains of northern thailand.
Ten months later, a british team of cave explorers sets
Out to conduct the first ever digital 3d survey
Inside tham luang cave.
They will journey deep inside.
Hoping to discover the truth behind the
Extraordinary events of 2018.
Leading the expedition is cave explorer roo walters.
Roo: When the divers entered these caves,
They couldn't see a thing.
They literally felt their way through.
So we're going to show what that passage was really like.
Narrator: Now that it's the dry season,
The team can penetrate the darkness to deploy the latest technology
And scan the cave in forensic detail.
Roo: It'll start to reveal just how clever and how
Inspirational this whole exercise has been.
Narrator: Even in the dry season,
Working here will be challenging.
After two hours, the survey team is in a squeeze.
Man: And then it closes down again.
Narrator: Trying to reach the place where the boys
Were eventually found, to begin their scan.
Man: How you doing there?
Yeah?
Narrator: They reach an area called chamber 9.
Roo: It changes direction here joe.
Joe: Yeah. Got a line up here.
Narrator: This rope, put in place by the rescue divers.
To help guide them through the silty water.
Joe: Oh. Wow.
Roo: Wow look at this! It's the end of the line joe.
Narrator: It was here the boys took refuge.
Joe: That's quite something isn't it?
Roo: That really is something...
Gosh!
Narrator: Left behind, foil blankets and remnants of
Survival from 18 days underground.
Joe: Wow. Not a lot of space is there.
Roo: It's not a lot of space.
Narrator: And an insignia, left by the four thai navy seals
Who joined the boys on this muddy ledge for 8 days.
Roo: This is incredible, absolutely incredible.
Joe: It's something else isn't it?
Roo: It's emotional, it is.
Narrator: They can now start scanning the cave.
Sending out 300,000 laser beams a second
And recording every reflection back from the cave walls.
The team hopes its data will explain exactly how
The boys got trapped.
Ten months earlier, the first rescue team was on site.
A mile inside the cave they made an alarming discovery.
The passage they knew the boys had taken just hours earlier
Was now, full of muddy water.
Where had it come from?
And why had it risen so quickly?
To find out, the survey team must scan the cave system from
Where the boys were trapped, all the way to the entrance.
The team works its way through the tunnels,
Scanning every crack and fissure.
Roo: Alright joe? Joe: Yeah all good.
Narrator: After half a mile they reach a point they think
Is critical, called sam yek junction.
Roo: I think this must be sam yek junction guys.
Joe: Yeah.
Narrator: The data they collect at sam yek junction will be vital.
Feeding it into powerful computer software,
We can now recreate the first section of the cave system,
In perfect 3 dimensional detail.
This is chamber 9 where the boys were finally trapped...
And this, the half mile long passage back...
To sam yek junction.
But a closer look at sam yek reveals a clue.
Another tunnel, monks series, joins the main cave system here.
In the rainy season when these caves fill with water,
Sam yek becomes the meeting point for two underground rivers.
Water finds its way through the cracks and channels of the
Limestone mountains into tham luang's cave system.
Vern: This mountain is just a big sponge and during the
Rainy season there's a huge volume of water travels
Through tham luang cave, basically like a big river.
Narrator: Back in 2018 when the boys and their coach
Started exploring, there was no sign of rain.
They had no difficulty walking through sam yek junction.
But outside, the weather was changing fast.
The heavy monsoon rains had arrived weeks early.
Almost an inch of rain fell in an hour.
Water seeped through the limestone mountains,
Funneling down into tham luang.
And then at sam yek junction, the other passage,
Monks series, brought yet more water into the cave.
At sam yek's narrowest point the junction filled in just an hour,
Flooding it to the roof.
The boys were now sealed inside the cave system with no way out.
Roo: Sam yek is the crux of this story and the 3d model
Clearly shows how that water then flooded the cave and
Entrapped the boys.
Vern: It was very isolated.
There was actually nowhere for them to go.
Narrator: As rain continued to fall...
Water levels rose further.
Forcing the boys deeper inside as they looked for higher ground.
So how did they survive?
♪ ♪
Narrator: Desperate local officials called in the
Country's elite divers to search for the boys.
The thai navy seals...
But the still rising water and strong currents forced them back.
Omar (over tv): Relentless rain is jeopardizing an
Already risky operation.
Reporter (over tv): They believe that there has been
Flash flooding inside.
Omar (over tv): The desperate race now is to find another way in.
Narrator: Above ground armies of cavers scoured the
Mountains looking for a way into the cave from above.
The search was gathering momentum.
On day 9, a breakthrough.
Electric pumps reduced the water levels.
Making it safe enough for the navy seals to dive.
They hunted for signs of life, deep inside and laid a
Guideline to mark their route back to safety.
Josh: We didn't really know exactly where the boys were.
I thought it was probably more likely they were dead than
Alive at that point.
Narrator: But they weren't dead.
So how did they survive?
Revisiting the data of the flooded cave reveals the answer.
This is sam yek.
Where the water rose quickly, trapping more water behind it.
But here in chamber 9, the boys managed to find refuge.
Discovering a solitary shaft off the main passage.
They scrambled up 14 feet above the water line.
It's a safe haven, in a dark lofty hollow,
That reaches 124 feet above the rest of the cave.
This was the only space in the cave in which the boys
Could have survived.
But a closer look at the cave data shows an intriguing anomaly,
At the highest point of the boy's refuge a small cavity,
Two and a half feet wide and 9 feet long.
Roo: It doesn't look like a normal piece of cave it really
Sticks out and that's because it isn't.
Narrator: Revealed in the data, for the first time,
A tunnel the boys dug out.
Roo: It's amazing.
Little stone tools are still there,
Scratches in the sides of the walls are still there.
What must have been going through their minds as they dug
With no idea of how far underground they are.
Narrator: Could the boys have dug themselves out from chamber 9?
How far underground were they?
To find out, the team need to do more than just survey
Inside the cave.
They must also discover exactly where tham luang lies,
Beneath the mountains.
The investigation takes to the air.
Roo: We can connect the cave 3d model to the surface model
And from that we'll actually be able to work out exactly
How far the boys were underground.
Narrator: Combining this aerial data with the underground scan,
We can pinpoint exactly where the boys were
In the mountain,
One and half miles from the cave entrance,
And above them, lay 2,000 feet of solid rock.
Accurately revealed for the first time,
The boys' complete isolation.
Digging a tunnel was futile.
Roo: What we've discovered, is just how remote the boys were.
It must have been terrifying for them.
Narrator: Dive teams had searched the flooded cave for days.
Two british cave-divers joined them,
Helping to lay more guideline.
Then, a mile and a half inside...
Reporter (over tv): Dramatic scenes in thailand.
Reporter (over tv): Against all odds rescuers in thailand
Have found 12 missing boys.
Reporter (over tv): Well what an amazing day.
Reporter (over tv): For family members pure elation after a
Heart-breaking waiting game.
Narrator: The boys had survived underground for
10 days with only the water dripping from the cave walls
To sustain them.
Within hours the thai navy seals delivered food,
Medicine and foil blankets to prevent hypothermia.
But one thing was on everyone's minds...
Vern: Very quickly we realized that our problem was only just beginning.
Josh: Finding them is one thing but what are you gonna do next?
Narrator: The thai authorities were desperate to find a simple solution.
But it would take another 8 days of nerve-wracking and
Dangerous work to get the boys out.
Martyn: Little did we know how long and how complex that
Operation was going to become.
Narrator: The thai authorities identified three options...
One: Wait for the monsoon rains to pass so the boys
Could walk out of a dry cave.
But that would take months.
Two: Find another route into the cave from above.
But a week of mountain searches discovered only dead ends.
That left option three, the most extreme-sounding of all.
Reporter (over tv): Are they gonna have to learn how to scuba dive
Their way out of there I mean that's really a tall order.
Reporter (over tv): Yeah it's crazy isn't it.
Pasakorn: We came to the conclusion that the only way
To bring the children out was the same way they went in.
Martyn: The prospect of a diving rescue was hideous from the outset.
Narrator: What is it about diving in tham luang that
Makes it just so dangerous?
Narrator: It takes three weeks for the survey team to scan
Tham luang cave.
All the way from chamber 9 to the cave entrance.
The boys were one and a half miles inside.
But they were safe, and divers had managed to navigate the
Flooded tunnels to reach them.
So why was it so difficult to get them out?
To understand, takes big data.
The team pieces together nearly 400 scans and
Builds a virtual cave system...
Roo: So this is full res.
Joe: The detail in that roof is fantastic.
Narrator: A new visualization of this underground world.
Roo: We will start to be able to show everybody what this
Cave is really like.
It is gonna be quite magical.
Narrator: With the world's first 3d digital survey of tham luang
We can reveal the second section of the cave system,
All the way from chamber 9 to the entrance.
8.7 billion data points,
More than 7000 photographs,
Come together to build the flooded cave as it was in July 2018.
Draining its water, for the first time....
Exposes all of its subterranean secrets.
This is chamber 9 to sam yek
And now, the rest of tham luang cave,
A narrow tunnel, that widens to the entrance.
All together one and a half miles,
The boys' only route out.
Adding the water level of the time to the digital map
Reveals why tham luang's passages can be so lethal.
In some places, underground canals formed.
In others, the cave flooded to its roof,
Fully submerging the passage,
In five sections known as sumps.
The longest sump lay next to chamber 9, over 1,000 feet long,
The length of seven olympic swimming pools,
Taken together there were half a mile of sumps,
Standing between the boys and safety.
And the visibility was almost zero.
The only way to escape chamber 9 was a long
Perilous cave dive with air tanks,
A potentially deadly option,
Even for thailand's diving elite, the navy seals.
Jongklai: The thai navy seals who assisted with the rescue
Had only trained in open seas.
They'd never dived in very narrow spaces.
Narrator: They needed specialist help.
A local caver, vern unsworth, had been part of the
Search and rescue mission since day one.
After seven years exploring tham luang he well understood
The challenge ahead.
Vern: We needed expert people out here, and, you know,
At the end of the day it was the right decision.
Narrator: He gave the thai authorities a list of some of
Britain's most experienced cave divers.
An elite team arrived, including john velanthon,
Rick stanton, jason mallinson and chris jewell.
They are among just a small group of people in the world
Who had the unique skills needed inside tham luang.
Chris: When we realized this was the best chance of the
Boys getting out alive,
Then we were determined to give it our best shot.
Narrator: A rescue plan developed.
From the entrance, the first half mile of cave was dry.
At the end of it, chamber 3.
This would be dive base.
From here, four cave divers would head deeper
Into the flooded cave.
Three hours later they would reach the soccer team.
Four boys would be equipped with scuba gear.
Then each diver would return with one boy
At 30-minute intervals.
If everything went to plan, it would take a full day to
Extract four boys.
On their way out, each diver and boy would need
Replacement air tanks.
So, they placed 50 of them throughout the cave and seven
Support divers would wait between sumps to haul
Equipment and provide medical backup.
It was a rescue plan like no other.
Chris: The situation in thailand was unprecedented.
Nothing like this has, has ever happened before.
Not those kind of distances and certainly that number of people.
Narrator: There were nearly 100 divers on site.
Emergency services, the us army and volunteers,
Also out in force.
All prepared and rehearsed for the first underwater extraction.
At 1:30 am, tragedy.
Vause (over tv): Breaking news out of thailand.
Where a former thai navy seal has died during rescue operations.
Narrator: Saman kunan, seen here with the rescue team,
Was on an overnight mission to place air cylinders
Inside the cave.
It's believed his own air ran out.
Reporter (over tv): This has taken on a whole new level of
Seriousness, there's a sense of mourning here today.
Reporter (over tv): It's raised serious doubts about
How they'll get the 12 boys and their coach out alive.
Narrator: How would the boys escape a cave that can kill
Even the best divers?
Narrator: Diving in tham luang had already taken one life.
It was an even greater threat to children who
Had never dived before.
But the greatest danger of all, lay not in the cave,
But in the heads of the boys themselves.
Martyn: If you take an inexperienced person underwater
Then there is a high probability that they're going to panic.
How were they going to cope with something as traumatic
As the prospect of diving, where you can't see
Your hand in front of your face?
Jason: If they'd have panicked underwater they could have not
Only killed themselves, they could have dragged our
Regulators out of our mouths we didn't want them to die and
We didn't want to die ourselves.
Narrator: So the divers made the most radical decision of the rescue.
To sedate the children.
Jason: It was a consensus amongst all the divers.
We weren't going to risk doing it without them being sedated.
Narrator: Doctors tailored a different mix of anesthetics
For every child, depending on age and weight.
No one had ever attempted to dive with unconscious children before.
Martyn: Having to sedate these youngsters to such a level
That they were incapacitated but remain alive,
And then be thrust into the cold water was an
Extremely risky proposition.
Jason: As we were planning it we were thinking,
You know it could be some of these kids that are gonna die.
Narrator: And as our cave data reveal,
Using a sedative left the cave divers with a
Further complication.
To extract each boy through the five sumps
Would take three to five hours.
But a safe dose of the sedative would last just an hour or less.
And so, to prevent the boys from waking,
The divers would have no option,
They'd have to inject them during the rescue.
Jason: Never actually done it before and yes it was the first time.
I was quite nervous obviously.
Narrator: And they could do that only in the dry parts of the cave,
Between sumps, not underwater...
Something that would bring diver jason mallinson close to disaster.
Nature was not on the rescuer's side.
More rain was forecast.
Pasakorn: If we didn't rescue them immediately we might have
Had even bigger problems.
Narrator: They scheduled the extraction.
Narrator: As more monsoon rain closed in,
The divers headed inside tham luang.
The boys had been underground for 16 days.
The most dangerous cave diving rescue in history was about to begin...
Vern: We honestly believed that there would be an attrition rate,
If two of them came out alive that would've
Been a good result.
Narrator: And the world was watching.
The rescuers began their dive to chamber 9.
Jason mallinson volunteered to run the first rescue.
The life in his hands was 14 year old prachak sutham,
Nicknamed note.
Jason: Until that first flooded section was traversed
By myself and the boy, nothing else could move forward
Narrator: Together they would discover if a rescue was possible.
They fitted a single air tank to note's chest and gave him a
Buoyancy vest with straps for jason to hold.
In case contact was lost, a safety tether joined boy to rescuer.
To stop note's mask being dislodged,
Jason would shield the boy's head with his own body and
Finally, for both their sakes, note's hands were tied to his
Sides in case he awoke.
Around 1 pm jason and note began the first journey out.
With the cave data we can do something impossible up to now.
Use technology to see through the muddy water to relive the
Most dangerous cave diving rescue of all time.
And reveal tham luang in a way that even the divers
Were unable to see.
This, the first sump, 1,000 feet long, underwater.
And the dive line their only chance of finding their way to safety.
Jason: The worst fear was losing contact with the
Guideline and losing contact with the boy.
We felt a tremendous amount of responsibility for the boys,
A child's life that's in your hands, a child who's asleep,
A child underwater.
I was nervous a lot of the time.
Narrator: At half hour intervals,
Three more divers entered the first sump with three more boys.
Not far behind jason and note,
Were diver chris jewell and 15 year old nick.
Separately each pair approached tham luang's first constriction.
Jason: First time you know about it is when you hit the roof.
Narrator: A low passage, just 30 inches high,
Little room for error.
Chris: My back would be against the cave roof and my
Chest would be against the floor of the cave.
Narrator: The dive line was difficult to follow as it
Meandered between the cave walls.
Chris: I was often bouncing off the rock and having to
Kind of back up and try and go forward again into different spaces.
Narrator: One after the other the divers felt their way
Through the sumps carrying their precious cargo.
Chris: We might knock the mask off so we were trying to go
Through these small spaces quite carefully, taking our time
Whilst holding onto the dive line in one hand
And holding onto the child in the other hand.
Narrator: But the sedatives were beginning to wear off.
Making an already difficult situation, life-threatening.
Jason: You'd be diving along underwater and you could feel the hands twitching.
Narrator: Revealed accurately; the scene of one perilous incident.
Between dives, jason was able to surface,
But he was still chest deep in water.
Jason: I was in a deep canal; I was on my own and there was
No dry place to put the boy and I needed to inject the
Sedative into his thigh.
Narrator: Ahead of them, the second sump, another 1,000 feet underwater,
Jason had no option but to inject the sedative
Right where he was.
Jason: I was trying to undo the dry bag with two hands but
Keep control of the child as well.
It was quite hard to hold him I had to sort of pin him
Against the wall with my leg, try and get all the syringes
Out of the bag, they all started floating around in the
Water and I'm trying to get the, the syringes.
I was quite nervous obviously,
And I managed to bring his leg up,
Put the sedative into his leg.
Martyn: The whole thing is really fraught with mental strain.
Jason: High stress, that's for sure.
Narrator: After two grueling hours,
Rescuers and boys had traveled through four sumps
Along a mile of cave.
But it wasn't over.
Ahead lay a dive in the final sump and the tightest squeeze of them all.
Narrator: Following the dive line the survey team locates
Tham luang's worst pinch point.
Roo: Look at this constriction.
Man: Doesn't look very nice.
Roo: Gosh that's small.
Narrator: How would a diver and a child fit through here?
The 3d data exposes the problem,
Over 100 feet into the final sump.
The dive line goes through a curtain of stalactites.
A gap just 20 inches wide at its narrowest point.
Jason: You couldn't fit through the stalactites.
It's certainly the most difficult part of the cave to navigate.
Narrator: But the data reveals something the divers couldn't see.
Below the dive line, a wider passage, 6 feet deep.
But making use of this space, by feeling a way through,
Was risky.
Chris: You have to back out, pull the line and find the
Biggest space that you could work your way round.
Jason: We had to pull the line down,
Stretch it down and go under the stalactites.
Narrator: By pulling down on the dive line the divers could
Swim beneath the pinch point.
But the extra tension on the line made it harder to hold on to.
Jason: There was always potential for it to slip
Through your fingers and then spring up into the roof.
Narrator: Slowly and carefully,
The divers made it through without losing the line,
This time.
By late afternoon jason had been caving and diving
For five hours.
Awaiting them in chamber 3, the international rescue team.
Jason: You just knew that you were seconds away from
Surfacing and being able to pass responsibility for that
Boy's life on to somebody else.
Josh: The cave line would start to get some tension on it,
Like a fishing line and so the guys in chamber 3
Would radio up 'fish on' because that meant a diver
Was pulling on the line, coming toward them.
Jason: I was very relieved to have got that first boy out alive.
Narrator: Expert cavers and medics took over.
They carried and hoisted note in a stretcher through the
Final half mile of cave.
The first four boys were out of tham luang cave.
All alive.
Reporter (over tv): Mission impossible has now become
Mission incredible.
Reporter (over tv): Well this is what all of those who've been
Involved in this operation have been waiting to see,
The boys are coming out.
Chris: The buzz was amazing.
It was quite incredible that we got the first four out
We weren't sure we would.
Vern: Emotions were running high, um,
As you can probably tell, now, um, absolutely amazing.
Narrator: Eight more children and the coach remained inside.
A further energy-sapping 8 hours of diving and caving for
Each rescuer, lay ahead.
Chris: We needed to do it not once more, but twice more.
Narrator: The divers headed back for a second group of boys.
It was another success.
Reporter (over tv): Four more boys emerging from that
Cramped and flooded cave.
Reporter (over tv): All are now in hospital in nearby chiang rai...
Narrator: There were just four boys and the coach left to rescue.
But the drama was far from over.
Chris jewell was diving out with the 11th boy,
13 year old sompong jaiwong.
Josh: It's very easy to forget the 11th dive is
As dangerous as the 1st dive.
Narrator: Two hours in, chris entered the last sump.
Chris: I had the last bit of diving to do.
I thought I'd sussed it.
Narrator: The 3d data reveals the dive line goes around a corner,
Where it is pulled tight beneath a boulder.
For chris, the tension on the line proved too much.
Chris: Through the process of going round that corner I was
Stretching the line with my hand and it just slipped out
Of my fingers.
When you lose the line in an underwater cave
That's really bad news.
I couldn't see which way to go.
Narrator: Time was running out,
Both chris and the sedated boy were using up
Their limited air supply.
Chris: I was sweeping with my arms, trying to pick up the line
And I couldn't find the line.
The most important thing is not to panic.
Narrator: The data reveals that as chris felt for the line
It lay just within arm's reach,
But in zero visibility,
Finding it was a matter of chance.
After 4 long minutes, chris discovered not the line,
But an electrical cable,
Laid in the early days of the rescue.
Instead of leading chris out, it led him all the way back,
To the start of the sump.
Chris: Thankfully I realized I was back somewhere that
I was familiar with.
Narrator: In the dry cave chris found the line and
Continued his rescue.
Against all the odds,
The rescuers completed their mission.
Itn: They are safe, they are out, they have done it!
Reporter (over tv): They have been rescued from that flooded cave.
Reporter (over tv): Millions of people are breathing easier tonight.
Narrator: After an intense struggle with nature.
The agonizing wait was over.
Vern: Unreal, amazing, 13 out of 13,
It's not an unlucky number anymore.
Chris: Things that seem impossible aren't always so.
Difficult things can be achieved and amazing things can happen.
Pasakorn: None of us were doing this out of duty
But out of a desire to save them.
Roo: I remain in absolute awe of everybody that took part
And the wonderful story that this is.
Narrator: Three months later, on british tv,
Divers chris and jason were reunited with the boys
Whose lives they'd saved.
Jason: I didn't know any of their names.
I remembered them by numbers 1, 5, 9, and 13.
(applause).
I think they really wanted to connect with the people that
Had brought them out so it was a really nice,
Nice thing that.
Translator: You are my heroes,
Thank you very much from the bottom of our hearts.
We love you.
(applause).
Captioned by cotter captioning services.