[AUDIO LOGO]
LESLIE STAHL: Last year's collision
of a passenger jet and Army helicopter
in Washington, DC killed 67 people.
For the first time, you will hear
from an air traffic controller who worked inside the tower.
Was there pressure to get more planes in and out?
And what we discovered about continuing problems
at that airport.
Why do we always have to wait until people die to take action?
[AUDIO LOGO]
LESLIE STAHL: Forget everything you
think you know about warfare.
The traditional front line in Ukraine has expanded
to a 10-mile-wide swath, where anyone spotted by a drone can be
hunted down.
[GUN FIRE]
[EXPLOSION]
Tonight, lessons from Ukraine's kill zone.
Necessity is the mother of invention.
[AUDIO LOGO]
Excellent, Scott.
That's really good.
SCOTT PELLEY: Nothing could prepare us
for the majesty of the largest cave passage on Earth.
Skyscrapers would fit in here.
A 747 could fly through.
Maybe most remarkable, all of this
was discovered only recently.
And there aren't a lot of places on Earth
that you can discover for the very first time.
No, you have to look pretty hard for them.
[AUDIO LOGO]
I'm Leslie Stahl.
I'm Bill Whitaker.
I'm Anderson Cooper.
I'm Sharyn Alfonsi.
I'm Jon Wertheim.
I'm Cecilia Vega.
I'm Scott Pelley.
Those stories.
And in our last minute, a Final Four legend
has a game plan for America, Coach Mike Krzyzewski, tonight
on 60 Minutes.
[AUDIO LOGO]
It was a week of chaos at airports across the country.
Gridlock in Washington left TSA workers without pay,
triggering four-hour security lines
in some of the nation's busiest airports.
Last Sunday, a commercial jet crashed into a fire truck while
landing on a runway at New York's LaGuardia Airport.
Dozens were injured, and two pilots were killed.
Authorities are investigating, but the air traffic controller
on duty said they were dealing with an earlier emergency,
and soon after the accident said, I messed up.
It is a chilling reminder of just how thin our aviation
system is stretched.
Last year, American Airlines flight 5342
and an Army helicopter collided over the Potomac River near DC--
the deadliest aviation disaster in almost a quarter century.
Tonight, you will hear from an air traffic controller
who was inside the tower.
The day of that collision.
She tells us why.
Controllers at Washington's busiest airport
have been warning of danger for years.
It is a story of a system pushed to the breaking point
and the shattered families left to pick up the pieces.
In southern Maryland, seven widows
whose husbands were on flight 5342
agreed to share their story together for the first time.
The men, all work buddies, met up with friends in Kansas
for a week of duck hunting.
The women shared these photos with us and the excitement
their husbands felt leading up to the trip.
Alex got home from work, and he was
like, before you say anything, it's already paid for.
[LAUGHTER]
And I was like, when do you leave?
There was no asking any more questions.
He was so excited to go.
It literally looked like Christmas morning in his face.
SHARYN ALFONSI: Kayla Huffman's husband, Alex,
posed with the crew and their trophies.
Bridget Johnson was married to Steve for 19 years.
Kylie Pitcher's husband, Jesse, owned a plumbing company.
Ashley Stovall's husband, Mikey, was a steamfitter, so
was Charlie, Heather McDaniel's husband.
HEATHER MCDANIEL: I met Charlie on the softball field.
And he basically, from that day, always said,
I knew I was going to marry that girl.
Because you were that good of a softball player?
Well, that, too, yes.
[LAUGHTER]
I gave him a run for his money.
SHARYN ALFONSI: When the hunting and fun was over,
the men headed to the airport.
Sarah Boyd's husband, John, checked in from the plane.
SARAH BOYD: John had texted me when he first boarded and said,
"boarded, Bourbon in hand."
[LAUGHTER]
And then right before they landed, he said,
"about to land this bird."
SHARYN ALFONSI: Jill Clagett was tucked into bed
with her young daughters, waiting for her husband
Tommy when the phone rang.
And then I kind of slid out of the bed not to wake them up.
And I turned on the TV, and I remember just
seeing the explosion.
DISPATCH.
Fire command.
The accident happened in the river.
SHARYN ALFONSI: Families raced to the airport
as divers searched the icy Potomac.
By morning, they were told the rescue mission was over.
I literally screamed, what am I going to do?
I got to the point where his friends were calling me at 5:00
in the morning.
And they were like, is he OK?
Is he OK?
I said, no, he's dead.
He's gone.
And it's no longer a rescue.
It's a recovery, which means there's no survivors, none.
SHARYN ALFONSI: As the wreckage was pulled from the river,
federal investigators began a year-long forensic autopsy
of the collision.
Video shows the American Airlines jet, seen here
on the right of your screen, pulled up just before it
and the Army helicopter collided.
There were obvious cracks in the system.
There were obvious holes.
SHARYN ALFONSI: Emily Hanoka says
she saw those holes during her time
as an air traffic controller at Ronald Reagan Washington
National Airport, commonly known by its airport code, DCA.
Her shift in the control tower ended a few hours
before the fatal crash.
She is speaking for the first time about the stress conditions
that she believes set the stage for tragedy.
So you had front line controllers
ringing that bell for years and years saying, this is not safe.
This cannot continue.
Please change this, and that didn't happen.
SHARYN ALFONSI: For more than a decade,
air traffic controllers warned the Federal Aviation
administration that the tempo of passenger jets and beehive
of army, police, and hospital helicopters near DCA
was a recipe for disaster.
The NTSB confirms between 2021 and 2024,
85 near-midair collisions between helicopters
and commercial aircraft at DCA were reported to the FAA.
And 60 Minuteshas obtained documents that reveal just one
day before last year's fatal crash,
two separate passenger jets had to take sudden action
to avoid colliding with Army helicopters.
EMILY HANOKA: The warning signs were all there.
Controllers formed local safety councils.
And every time that a controller made these safety reports,
another controller was compiling data
to back up the recommendation.
And many recommendations were made,
and they never went too far.
SHARYN ALFONSI: DCA is unique-- it's
owned by the federal government, and the number of daily flights
is ultimately determined by Congress.
Since 2000, lawmakers added at least 50 flights
to the already congested airport and approved another 10 in 2024.
EMILY HANOKA: Some hours are overloaded
to the point where it's over the capacity
that the airport can handle.
Was there pressure to get more planes in and out?
Yeah, there was definitely a pressure.
If you do not move planes, you will gridlock the airport.
SHARYN ALFONSI: DCA moves 25 million passengers a year,
10 million more than its intended capacity.
Its location near the heart of DC
makes it popular but also problematic.
Restricted airspace near the airport
shields the White House, the US Capitol, and other government
buildings.
For years, funneling planes and helicopters
into the same narrow corridor over the Potomac.
And Hanoka showed us on her map of the airspace
why the tarmac is just as tricky.
There are only three short runways at DCA,
and none are parallel.
And so if a plane's coming in because these runways intersect,
everything is connected.
Everything is connected.
There is no independent operation at DCA.
SHARYN ALFONSI: DCA's main runway, runway one,
is the busiest in the country with over 800 flights a day,
roughly one every minute.
To make it work, Hanoka says air traffic controllers often relied
on what they called a squeeze play.
EMILY HANOKA: A squeeze play is when everything
is dependent on an aircraft rolling, an aircraft slowing,
and you know it's going to be a very close operation.
So they're really just one's going up
and one's going in at the same time?
And that is a really common operation.
SHARYN ALFONSI: Two airplanes on one runway
within seconds of each other.
Is that normal at other airports?
EMILY HANOKA: No.
So you'll get new controllers come in.
So they've transferred from other facilities,
and they'll look at the operation
and say, absolutely not.
And they'll withdraw from training.
When I was there, it was about 50%.
50%?
About half of the people that walked in the building to train
would say, absolutely not.
SHARYN ALFONSI: A year after the crash, nearly one third
of the controller positions in the DCA tower are unfilled.
EMILY HANOKA: It was surprising walking
into that work environment how close aircraft were.
SHARYN ALFONSI: It was just kind of accepted there?
EMILY HANOKA: Yeah.
This is what has to happen in order
to make this airspace work, and it did work.
It worked until it didn't.
SHARYN ALFONSI: In January, the NTSB
determined the midair collision of Flight 5342
and the Black Hawk helicopter was preventable.
In its 388-page page report, investigators didn't identify
a single cause of the accident.
Rather, they called out systemic failures,
including ignored warning signs about risks
and a helicopter route that was designed
so poorly that in some parts of the sky,
it allowed for just 75 feet of vertical separation
between helicopters and passenger jets.
TIM LILLEY: I flew these routes hundreds of times.
SHARYN ALFONSI: During his 20 years in the Army,
Tim Lilley flew Black Hawk helicopters often
down the Potomac River near DCA.
The night of the crash, investigators
say the Black Hawk crew was relying on what's
called visual separation.
Literally, just looking out the window
to avoid nearby passenger jets.
TIM LILLEY: To apply visual separation,
the pilot has to positively identify the other aircraft.
And say, that's the plane you're talking about?
That's the plane.
And he has to maintain constant surveillance
on that aircraft, which is impossible
under these conditions.
SHARYN ALFONSI: Impossible, he says,
because the crew was likely wearing night vision
goggles, which Lilley says limit what a pilot can see.
Help people out with this at home,
because I think we've all watched enough movies where
you see somebody put on night vision goggles,
and they can see everything.
But that's not the case.
Especially under these conditions, that's not the case.
So when you have a lot of bright lights
like you do in Washington DC area,
everything gets washed out through the goggles.
PILOT: Air Carrier One to Washington star altimeter, two
niner niner 0.
SHARYN ALFONSI: The NTSB built this simulation
to show what those Black Hawk pilots saw or, rather,
what they couldn't see.
That green circle indicates the pilot's view
wearing night vision goggles.
That purple circle is the American Airlines jet
they were supposed to be looking out for.
You can see how it's hard to distinguish between an airliner
and ground lights.
Night vision goggles also limit peripheral vision,
so the crew on a training mission
didn't see flight 5342 until it was too late.
TIM LILLEY: So the proper way to fly that is constantly scanning,
always moving your head side to side because your field of view
is limited with goggles.
But why is that kind of training
happening in this airspace where it's so busy?
The military would say, this is where our mission is.
This is where we need to train.
And to some degree, I agree with that.
But those training environments, they
should be nowhere near commercial airliners, right?
SHARYN ALFONSI: Tim Lilley is now advocating for changes
to make the skies safer.
His son, Sam, shared his love of aviation.
And in the cruelest twist of fate,
was the first officer on American Airlines flight 5342,
one of the 67 killed in the crash.
TIM LILLEY: And I never thought to warn him
about the helicopters because I just
didn't realize how far the safety margins had slipped
since I had flown those routes.
This was a system that failed the people on the aircraft,
on the helicopter, in the air traffic control tower.
SHARYN ALFONSI: Jennifer Homendy is the chairwoman of the NTSB.
After a yearlong investigation, the agency
suggested 50 safety recommendations
to prevent similar accidents.
If everybody knows those close calls are dangerous,
then why didn't anybody step in and say, we
have to lighten the load here?
The air traffic control tower the entire time was saying,
we have a real safety problem here, and nobody was listening.
It was like somebody was asleep at the switch
or didn't want to act.
It is a bureaucratic nightmare.
SHARYN ALFONSI: Immediately after the accident,
the FAA moved some helicopter routes away from DCA
and ended the use of visual separation.
Earlier this month, it expanded that ban to busy airports
across the country.
In a statement to 60 Minutes, Transportation Secretary Sean
Duffy said he's helped secure more than $12 billion to, quote,
"aggressively overhaul our air traffic control system."
But the problems at DCA continue.
Since the crash, 60 Minutes has learned at least four
times aircraft and helicopters have gotten too close,
triggering safety reports.
It is unconscionable that we are having to be here right now.
SHARYN ALFONSI: Some of the families of Flight 5342
are now fixtures on Capitol Hill,
advocating for aircraft surveillance technology that
might have saved their loved ones.
Jennifer Homendy says if the FAA and lawmakers don't move quickly
on safety legislation, they are clearing
the path for another disaster.
I imagine most of them fly in and out of DCA.
They do.
So what would you say if they were listening?
I'd say, why do we always have to wait until people
die to take action?
[AUDIO LOGO]
Now, Holly Williams on assignment for 60 Minutes.
HOLLY WILLIAMS: When America went to war with Iran
last month, the US military faced an enemy
using mass-produced drones to deadly effect.
The same weapons have been used for years in Ukraine,
some of them supplied by Iran to Russia.
Unmanned and remotely controlled,
drones have transformed the Ukrainian battlefield.
They're estimated to inflict around 80% of combat casualties
on both sides.
The technology is nothing short of revolutionary,
and it's evolving rapidly, as we discovered,
to adapt to the new era.
The US military is learning lessons from Ukraine.
[DRONE BUZZING]
[GUN FIRE]
Forget everything you think you know about warfare.
[GUN FIRE]
The traditional frontline in Ukraine has expanded
to a roughly 10-mile-wide strip called the kill zone.
Anyone who sets foot there can be spotted by a drone operator
and hunted down.
[GUN FIRE]
[EXPLOSION]
[NON-ENGLISH SPEECH]
HOLLY WILLIAMS: This was a narrow escape
for some Ukrainian soldiers.
They call these Frankenstein tanks,
retrofitted with cages and mesh to deflect drone strikes.
Netting covers roads close to the front,
designed to catch them before they hit their target.
To evade interference from electronic jammers,
both militaries launched drones attached
to miles-long spools of fiber optic wire,
leaving behind a digital spider's web.
But the drones are not just in the air.
Continuously innovating.
Yes.
HOLLY WILLIAMS: Beside a frozen lake, Ukraine's security service
took us to see one of their most treasured weapons.
I mean, it looks a bit like a fishing boat scout.
That's an outboard motor?
Yeah, yeah.
HOLLY WILLIAMS: It's a sea drone developed
in Ukraine called Sea Baby.
We're protecting this operator's identity
because he's a target for Russian assassination.
What's the payload on this?
It can really take 2,000 kilograms.
2,000 kilos of explosives, is that enough to take out
a Russian warship?
Yes.
HOLLY WILLIAMS: Produced for around $300,000.
Ukrainian sea drones have destroyed warships
that cost tens of millions.
Ukraine says it's used them to sink or disable
11 Russian vessels.
Which one is more useful, a warship or a sea
drone like the Sea Baby?
OPERATOR: Sea drone.
I think it's really hard to destroy these drones
because they are smaller.
That's why to have a 10 ships like this is
much better than one big one.
Wow.
To be clear, you're saying you'd rather have
10 sea drones than a warship?
Yeah.
Necessity is the mother of invention.
HOLLY WILLIAMS: Oleksandr Kamyshin started out the war
as the CEO of Ukraine's railways.
He was so good at his job, helping millions of Ukrainians
to evacuate, that President Volodymyr Zelenskyy recruited
him to become the architect of Ukraine's drone program.
Cheap, fast, efficient.
HOLLY WILLIAMS: Kamyshin told us he helped boost
Ukraine's production from 2,000 drones a year to four million.
For the outnumbered Ukrainians, the inexpensive new technology
has allowed them to level the battlefield.
It's a data-driven war with big numbers.
It's a numbers game.
What do you mean by a numbers game?
We have to count everything.
We have to count number of drones we use,
efficiency of each of them, cost to kill for every Russian.
And what is the cost of killing every Russian?
You would be surprised, but the cost of killing every
Russian is less than $1,000 now.
That's why they sent so many people to die on the front line.
They don't count them.
They don't value them.
Would you want to be in Vladimir Putin's shoes
right now?
No.
Strategically, he lost.
He wanted us to become weaker, became much stronger.
HOLLY WILLIAMS: 10 retired US generals
told us they agree that Russia isn't winning the war,
despite its territorial gains.
Some cautioned that Ukraine isn't winning either.
But with the help of drones, has managed to draw Russia
into a stalemate.
This is like a kind of obstacle course for drones.
Ukraine's military has set up drone training academies
to teach the new technology--
Patience and practice.
Yes.
I mean, practice makes perfect.
Am I right?
HOLLY WILLIAMS: --and the rapid shifts
in tactics that come with it.
This ground drone, mounted with a 50-caliber machine gun,
recently held off a Russian attack single-handedly for 45
days straight.
In January, three Russian soldiers
surrendered to a similar robotic drone.
ROMAN TKACHENKO: Our main idea, if we
can send the robot and to not risk the human life.
So the first, it's a human life is the most important.
HOLLY WILLIAMS: Ukraine says it makes more than 95%
of its own military drones, harnessing talent
from some unusual places.
Roman Tkachenko is a former brewery engineer
who founded a company called Tencor and developed
these remote controlled armored evacuation drones
to transport wounded soldiers.
They gave us a demonstration at a military training ground
and claimed the drones have saved hundreds of lives.
How do you figure out what your next design needs to be?
ROMAN TKACHENKO: We are working with the end users.
HOLLY WILLIAMS: End users, that means the soldiers who
are on the front line.
ROMAN TKACHENKO: Yeah.
HOLLY WILLIAMS: The soldiers said, we
need a drone to do evacuations.
And you built it.
Yep.
That's how it works in Ukraine.
We are designing for soldiers.
HOLLY WILLIAMS: The same drone base can be adapted to mount
a 40-millimeter grenade launcher,
controlled from a bunker, which could be hundreds of miles away.
When it comes to drones, how quickly
is the technology changing?
Innovation cycle is roughly one week.
It means from the point you sent a drone to the front line,
get the feedback, change something, and get
the new version, it could be as short as one week.
Are the Russians also innovating?
Yes, definitely.
We have to admit it.
Who has the edge?
At this point, I would say that's equilibrium.
HOLLY WILLIAMS: Equilibrium in a drone arms race.
And both sides will take any help they can get.
Air Logics makes aerial surveillance drones
for the Ukrainian military-- their production spread
across more than 20 sites to minimize risk
because they've already been bombed twice by Russia.
It's a dangerous business, but the company recently
secured over $1 million from an American investment
fund that specializes in Ukrainian drone technology.
It's run by two former US Marines, William McNulty, who
has a background in humanitarian work,
and Lenore Caraffa, who built a career in finance after leaving
the military.
They told us their investors are wealthy individuals who
support Ukraine.
I worked at one or two jobs after the military
that were more about the money than anything else.
That is not my main motivation.
You didn't join the Marines for the money?
[LAUGHS]
What's your main motivation?
Service, patriotism, democracy, mission.
And Ukraine takes all of those boxes.
It ticks all those boxes.
I fell in love with the Ukrainians when I arrived.
How could you not?
And how could you not just come to help the people that
are literally fighting for what NATO is created for,
to stop Russian aggression?
HOLLY WILLIAMS: At a NATO training exercise in Estonia
last year, the alliance tested its vulnerability
against drones.
Around 1,000 NATO personnel were defeated in the drill by a group
of drone operators, some of them Ukrainian.
Is this a revolution in warfare?
It is.
No question in your mind.
No question.
In every war, there is innovation
from going from horses to tanks to machine guns,
and then tactics evolve in response to that.
And that is why it's just incredibly important for the US,
for our European allies to learn these lessons from Ukraine.
There's a real risk that the US
would lose its military supremacy
if it doesn't adapt to modern conditions on the battlefield.
We're going to be going up against these same unmanned
systems that Russia is using against Ukraine.
HOLLY WILLIAMS: The US military told us
it intends to hang on to its supremacy,
not by buying, stockpiling, or replicating Ukraine's drones,
but by tapping into the same passion for innovation
the Ukrainians have at the Wiesbaden Garrison in Germany.
SOLIDER 1: Cable channels you run through,
keep everything nice and flush.
HOLLY WILLIAMS: The Forge is one of dozens
of drone innovation labs set up by the US military
around the world.
SOLIDER 2: Props are good.
HOLLY WILLIAMS: Any service member
with an idea or just an interest can request to spend time
in one of the labs.
The legs slide out, and you just add a spacer.
RONAN SEFTON: It's adding a culture of innovation,
and that's new.
That's not something that we've really
seen in the last 20 years.
Is it possible that a soldier will
walk into one of those innovation labs
with an idea that could be a breakthrough
in drone technology?
It's entirely possible.
The thing with drones and innovation
is what I would describe as unlimited innovation potential.
If you can think of it, you can make a drone do it.
Expedited basic training.
HOLLY WILLIAMS: Captain Ronan Sefton
was first deployed to Germany with the Army's second cavalry
regiment, not long after Russia launched its invasion in 2022.
His job was to give basic training to over 8,000 Ukrainian
soldiers.
But he told us almost immediately
the Americans began learning from the Ukrainians.
RONAN SEFTON: The first really poignant lesson
for us was there needs to be more drones.
They need to be everywhere, involved
in the training to add to the realism.
So the Ukrainian soldiers were giving that to you as feedback?
Absolutely.
Did you then talk to your commanding officers about it?
We went to every senior commander we could.
The thing that we wanted to communicate
was this is important.
It's changing warfare, and here's
how we can actually implement it now.
We're already doing it.
We should scale this.
HOLLY WILLIAMS: The message got through.
And now Sefton's joined the Army's Ukraine Lessons Learned
Taskforce.
It has the job of translating experience
from Ukraine's scrappy fighting force
to America's sprawling military.
He told us the new technology does not make the US military's
traditional firepower obsolete, but it needs to adapt urgently,
countering the drones developed by America's adversaries.
You still need howitzers.
You still need Abrams, but you have
to figure out how to get the drones to work
with the howitzers and Abrams.
RONAN SEFTON: Exactly, and that's
the challenge, but also the goal to become ready
for the next conflict.
We see it with the armed forces of Ukraine.
They have learned these lessons through blood.
There will, of course, be additional lessons
that we will learn, perhaps through blood,
but it will only make us better at what we already are.
HOLLY WILLIAMS|: The day after that interview,
the United States went to war.
And the Iranian drones began flying.
[EXPLOSION]
The first Americans killed in the conflict
were targeted with a drone.
The US military is now learning its lessons in blood,
just as Ukraine did.
[AUDIO LOGO]
ANNOUNCER: The next breakthrough in battlefield drones?
HOLLY WILLIAMS: Drones working together like a swarm of bees.
Exactly.
Pretty scary.
It is scary, absolutely.
ANNOUNCER: At 60minutesovertime.com.
[AUDIO LOGO]
Imagine in the 21st century, discovering a marvel on par with
Mount Everest or the Grand Canyon.
It happened in 2009 with the revelation of the largest cave
passage in the world.
It's in Vietnam, and they call it Hwangseong-dong--
mountain river cave.
An intrepid British Explorer, Peter MacNab,
led the first team through this epic underworld of caverns,
the height of skyscrapers.
MacNab is to caving what Armstrong
is to the moon, the first Explorer.
Recently, we asked MacNab to show
us this wonder of the world.
But before we begin our trek, we really
have to show you a preview of where we're going.
Simply glorious.
This was the moment Son Doong caught us in its grasp.
Sunbeams cascading 120 stories from a break in the ceiling.
Groundwater above us slipping through the light like rain.
And rock reflecting what seemed like the only sound
in the world.
Not many have stood in this space that transcends time.
It was a reward for our journey that began days before.
The only way to Son Doong is on foot,
a trek of a day and a half.
We had a party of 53 moving in groups, mostly porters,
heaving camping and TV gear, plus experts in safety
and climbing.
There were 20 river crossings, water
flowing through limestone, two of the essentials for building
caves.
This is the slender center of Vietnam,
the Truong Son range between Laos and the South China Sea.
We were following the Vietnam war's Ho Chi Minh Trail,
through a jungle where Tigers are not unknown
and leeches are plentiful.
WOMAN: Oop, there's another one.
JON WERTHEIM: Leading us were explorers Howard Limbert,
whose work in Vietnam over 30 years discovered 500 caves,
and Peter MacNab, whom Limbert sent
to be the first in Son Doong.
PETER MACNAB: I find it an adventure going, exploring
and not quite knowing what's around the corner
and just finding your way through.
And things reveal themselves like big chambers, big passages
or tight, narrow bits, beautiful formations.
And there aren't a lot of places on Earth
that you can discover for the very first time.
PETER MACNAB: No, you have to look pretty hard for them.
JON WERTHEIM: You have to look pretty hard for the entrance
to Son Doong.
You'd hardly notice, but for the writing
on the wall proclaiming the miracle of Ho Khanh.
In 1990, Ho Khanh, a villager, discovered this entrance
after he sheltered here from a storm.
He told us--
HO KHANH: [NON-ENGLISH SPEECH]
JON WERTHEIM: --I was collecting wood.
I saw a sinkhole, and I felt something strange.
The strange feeling was wind blowing out of the ground.
Cavers know that's the breath of a tremendous cavern.
In 2,000 the British cavers asked young Ho Khanh to show
them, but it took eight years.
He'd lost it in the trackless jungle.
HO KHANH: [NON-ENGLISH SPEECH]
JON WERTHEIM: In 2008, I finally found it, he told us.
In 2009, they started exploring.
That exploration began here.
We're just inside, looking back toward the entrance above.
The first obstacle is a spectacular 30-story story wall
that our climbing team showed us how to descend.
Can you step to the left side?
JON WERTHEIM: Darkness would be nearly total,
but we lit it so you can see.
Peter MacNab was the first to do this.
In 2009, he and four others on his team
were dropping into darkness.
PETER MACNAB: There's an obvious big black hole where you're
heading towards, and you just skirt around and look around
and find this way is pretty good.
This way works.
Quite often, you get stopped, can't get down here.
You just basically feel your way through the cave
by trial and error.
[CHUCKLES]
You had no idea--
None whatsoever--
JON WERTHEIM: --what was beyond the light on your helmet.
PETER MACNAB: Yeah.
No, we didn't at all.
Every corner you went round was completely new, completely
exciting, and it just kept getting better and better
as you went into the cave.
It was absolutely spectacular.
JON WERTHEIM: Spectacular like the entrance
we just repelled down.
Look at the two men, halfway down holding lights.
At the very top is the entrance and the last daylight
we would see for a while.
At the bottom of the climb, we met the architect
of Son Doong, the Rao Thoung River.
Its waters are acidic, so it's really
good at dissolving limestone.
Well, this is a pretty good setting for an interview.
DARRYL GRANGER: Yeah.
JON WERTHEIM: In camp we spoke to Purdue University geologist
Darryl Granger, who came here in 2010 to figure out when
the river started its project.
We found a nice package of sediment further in the cave,
and that dated to about 2 and 1/2 million years ago.
JON WERTHEIM: That's when the river first found a tiny crack
in the limestone ridge.
DARRYL GRANGER: The width of a hair, maybe.
That's all it takes to make a cave.
The water started flowing through it
and dissolving it bigger and bigger and bigger.
We still have water going through it today,
so it's continuing to get bigger as we speak.
JON WERTHEIM: Our exploration of the cave
took three days and two nights.
The length is 5.6 miles.
It's 65 stories tall and the width of one and a half football
fields.
The Great Pyramid of Giza would fit easily.
A 747 could fly through the biggest passage
and not scrape a wing.
Sometimes, the only way forward was the width of our shoulders.
But we noticed in the broadest caverns,
you often lose the sense of even being underground.
What reminds you is the isolation.
No cell phone, no satellite, we were cut off from the world.
Roughly halfway, there was a light ahead.
There are two skylights where the roof collapsed.
For us, a break from total darkness and a chance
to show you the scale.
Geologists call these holes dolines.
The word has European roots.
It means sinkhole or depression.
And this doline formed because the roof
over our heads, the limestone, is
a little bit thinner here than it is in the rest of the cave.
Then, as the cave grew wider and wider and wider
over millions of years, it was unable to support the roof
above.
It all caved in right here.
What's remarkable about it is that it allows light
into this cave that would otherwise be utterly dark.
And it allowed the jungle to come inside the cave.
Like everything else about the cave, this doline is enormous.
It's 450 above my head.
In other words, about the height of a 45-story building.
We stopped here with Howard Limbert,
who's explored Vietnam since the '90s.
When my producer, Nicole young, suggested this story,
I turned her down.
I said, Nick, it's a hole in the ground.
What was I missing?
You're missing the best adventure
that happens in the world.
Something no one's seen before?
That's the beauty of caves.
If you climb in a mountain, you can see where you're going.
But in a cave, when you go in, you
don't know what it's going to do.
Your father was a caver.
PETER MACNAB: He was, yeah.
So he was a caver in Scotland.
JON WERTHEIM: Peter MacNab, the first in Son Doong,
has been caving since he was a boy.
You grew up in a cave.
PETER MACNAB: Not quite, but within a mile of it.
[LAUGHTER]
JON WERTHEIM: MacNab is a construction manager
in New Zealand-- big projects like hospitals,
but you get the sense he does that to pay for this.
In all the caving that you've done,
what is the closest call you've ever had?
I've been stuck.
I've had rocks collapsed, and I've been flooded in.
JON WERTHEIM: He was stuck a few years ago
when he went headfirst into a crevice
that cavers call a squeeze.
MacNab couldn't back out.
A partner found him and used a knife
to rip away his coat to give him the spare half-inch he needed.
Did he pull you out by your feet?
Pretty much.
[LAUGHS] Yeah.
You are still exploring this region.
Yes, yes.
We come back every two years, and we've barely
scratched the surface of the caves in this area.
JON WERTHEIM: There may be another biggest
cave in the world.
There could well be.
JON WERTHEIM: Truth is, MacNab's first expedition in 2009
never reached the end of Son Doong.
Beyond this underground lake, he discovered a 30-story wall
and ran out of time before he could scale it.
MAN: Take in, take in, take in.
JON WERTHEIM: We climbed it on our trek
and understood immediately why they call
it the Great Wall of Vietnam.
MAN: Keep the line tight.
Take in.
Excellent.
Take it in on the lifeline.
JON WERTHEIM: It's a 300-foot climb on slick rock,
with no foothold anywhere.
MAN: Take in.
Excellent, Scott.
That's really good.
Come right up to the corner.
JON WERTHEIM: [HEAVY SIGHING AND BREATHING]
It's challenging enough until you realize,
of course, you're doing it in the dark,
and it's essentially raining.
The groundwater is coming from the roof.
So with everything wet, you find yourself slipping back
while climbing up.
But our team got us up and over, drenched and a little exhausted.
Well, we saved the best for last.
We've made it all the way through nearly all the miles
of the cave over three days.
And now we just have a little bit further to go.
In fact, I can see the exit from here.
We could see it, that light up there,
but we still had quite a climb to make.
We learned by the end of our trek
that Son Doong may be even larger than we know.
Hundreds of feet below that lake,
behind us, the water is draining somewhere.
There could be more caverns beyond.
It's the work of millions of years likely to continue
for millions more--
unimaginable time, measured by a pendulum of light,
illuminating the splendor of one of the greatest marvels
on or under the Earth.
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ANNOUNCER: The last minute of 60 Minutes
is sponsored by UnitedHealthcare,
coverage your whole life ahead.
As America celebrates the 250th anniversary
of independence, we wondered about a game plan
for the country's future.
So Hall of Fame basketball coach Mike Krzyzewski
drew one up for us.
To build a championship culture,
you need talent and character.
You then develop the values of that culture.
The best teams have the best values.
We had seven-- integrity, do the right thing, respect;
everyone is important.
Courage, the courage to say or do what
needs to be said or done in that moment; selfless service,
loyalty, duty, the dignity of work, and trust.
Values-based organizations stand the test of time.
Our country has great talent.
And for 250 years, we have proven that we stand unshaken
by the tests of history.
Moving into the future, we must continue to teach,
celebrate, and most importantly, live
the values that have made America
the best country in the world.
[AUDIO LOGO]
I'm Scott Pelley.
We'll be back next week with another edition of 60Minutes.
ANNOUNCER: Go to the ends of the Earth.
We'll hit the heights.
[VOCALIZING]
ANNOUNCER: Reach for the stars.
Star power.
I like it.
ANNOUNCER: Experience thought-provoking--
Something that's undeniable.
Ta-da!
ANNOUNCER: --and truly original reporting.
I'm in on this.
ANNOUNCER: There's always something new
under the sun on CBS Sunday Morning.
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