Original subtitles

‐ ..."Lost Gold of World War II..."

‐ John: All the signs and symbols were pointing

last year to the waterfall,

and I believe there was a treasure under there.

The satellite made multiple hits right on the waterfall.

‐ We think we've got either a tunnel

or some type of void space.

‐ Is that a blade right there?

‐ Could mean that Americans were here putting this in.

‐ Keep it coming.

‐ Announcer: John Casey,

a construction contractor

from the U. S.,

is back in the Philippines

with a new team...

continuing his search for Yamashita's gold.

‐ We're gonna find a way to get to this treasure.

‐ Like many others, John believes

Japanese general Tomoyuki Yamashita

took billions of dollars in treasure

looted by Japan during World War II

and buried in the Philippines,

including somewhere in this mountain.

According to an eyewitness,

mysterious wooden crates were hauled up this mountain

by prisoners of war

and buried in tunnels, which were then destroyed.

‐ ...boom.

‐ Based on that account,

John followed a series of mysterious symbols

to three promising sites‐‐

a waterfall...

‐ This waterfall's hiding something.

‐ ...a crater known as Breach 6...

‐ I've never seen anything like this.

‐ ...and a camouflaged tunnel they uncovered last year.

‐ We are in the mountain, boys.

‐ Can they finally discover the...

In a remote area of the Philippine jungle,

John continues his long obsession

with the waterfall.

He believes these strange carvings

could provide clues to treasure

hidden under orders from the Golden Lily,

a group of Japanese power brokers

allegedly directing General Yamashita.

‐ I betcha that was a marker to our tunnel.

Right on top of this big rock!

You see that's definitely a box marker on that rock!

‐ Deeply rooted in Japanese culture,

waterfalls are believed to garner power and protection.

For centuries, Shinto priests buried valuables in waterfalls

for safekeeping, especially during wartime.

It's thought the Golden Lily followed this tradition.

And last year, John tried to find a way in.

‐ We're really having a hard time

digging around this big rock at the waterfall.

‐ But was defeated.

‐ We're gonna be here forever.

‐ A recent Nuclear Magnetic Resonance, or NMR scan,

suggests John's hunch could be right.

It shows a massive metal deposit

and a possible tunnel deep beneath the waterfall.

‐ It's like about 300 feet down.

‐ If the Japanese are burying big treasures

like the one that's up there,

it could be that deep.

NMR's saying we got a target here.

We got all these signs and symbols

that have been leading me to this location,

saying there's something here.

‐ But John has a problem.

‐ 300 feet's a long way down.

It's one thing to know where something is.

Doesn't mean you can always get it out.

‐ Standing in his way is 300 feet of solid diorite,

one of the hardest rocks on earth.

‐ I mean, the Japanese were specialists

at tunneling into hard rock.

‐ But drilling through rock this hard

requires a specialized 40‐ton machine

impossible to bring to this remote site.

‐ There's no way I can even get equipment up here

without a helicopter to bring it in.

‐ This kind of drilling process

also produces highly toxic waste water.

‐ Even if I could bring it in,

the whole water supply from the town below

comes from our waterfall.

We're not gonna be screwing with the town's water supply.

‐ These obstacles make drilling the waterfall impossible

for now.

‐ I got to figure out a way to get in there.

How am I going to get it out?

‐ As John looks for a way into the waterfall...

Miners Levi and Geo are battling Mother Nature

at the tunnel site.

‐ It's crucial that we get in there

and see where this thing goes.

It could lead to another tunnel.

It could lead direct to the treasure.

‐ This mysterious tunnel was discovered last year.

‐ We're in the mountain, boys.

‐ It's believed to be connected

to an elaborate network of tunnels

running deep into the mountain.

Recently, John and the team discovered a knife here.

‐ Aw, man, look at that.

‐ Looks like a handle to a knife.

‐ The find raises new questions‐‐

who else has been here

and what awaits them inside.

‐ After finding that knife,

seeing that there's still artifacts in here,

this thing hasn't been picked dry,

we definitely do not want to lose this at this point.

‐ Geo: Man, that rain is not letting up.

‐ We're dealing with a lot of clay and mud,

and now this rain we're getting,

it could cause a landslide

and we could lose everything we've worked for.

‐ They plan to use one of the team's two excavators

to install steel support beams at the tunnel's entrance

before the storm triggers another collapse.

But the muddy conditions

are putting that plan in jeopardy.

‐ I'd hang as close to that bank as you can.

It's messed up bad.

‐ Get over there, it's just frickin' sliding.

‐ Come on, baby.

‐ Come on.

Keep pinching.

‐ With the excavator unable to reach the site

and the threat of collapse increasing...

‐ Be careful, dude.

‐ ...Levi takes matters into his own hands.

‐ Get out of my way. I don't want to trip over you.

I'm a little bit worried about going in there

and rattling on stuff with all the water running through,

but that's just part of the game.

That's part of mining.

If mining was easy, everybody would do it.

This weather's not helping it,

but we'll get through this thing.

‐ As the miners work through the night

to shore up the tunnel,

Rick begins reviewing the nearly 100 hours

of secret tapes he obtained from an anonymous informant.

They feature a mysterious American

named Robert Curtis.

A mining engineer,

Curtis was recruited

by Philippine President Ferdinand Marcos in 1974

to help find Yamashita's lost treasure.

‐ Bob Curtis was in the Philippines

for three decades.

We've got video documentation

of Bob Curtis on dig sites all over the Philippines.

‐ The tapes reveal other valuable information as well.

In this deposition, filmed in 1991,

Curtis shares what he knows.

‐ Bob: President Marcos had been sitting for years

on a treasure trove

of fantastic sums of gold and other precious metals

which were buried in and around the Philippine Islands

by the Japanese.

President Marcos knew

where all this material was located,

and he was talking in terms

of hundred thousands of metric tons of gold.

‐ Announcer: Marcos also tasked Curtis

with decoding Golden Lily maps.

‐ When Marcos was ousted in 1986,

Curtis allegedly kept those maps,

using them to aid his own treasure hunts‐‐

hunts he documented on tape.

After analyzing hours of video shot by Curtis,

Rick shares what he found with John and his brother Rob.

‐ There's a ton we can learn from this, man.

Listen to this.

‐ ‐

Our chamber is 300 feet down.

‐ We're finding a lot of similarities,

especially large geographical landmarks‐‐

waterfalls on a couple of these other projects

very similar to what we've got.

‐ Did you hear what he said?

‐ Yeah.

He sent two guys off to find the hole.

Listen to this.

- ‐ Ooh. - ‐ Holy.

That could mean there's another way into our waterfall.

‐ Based on similarities

between their waterfall site

and the one described by Bob Curtis on tape,

the team believes there might be another way

under the waterfall.

‐ The whole process is a huge gamble right now.

We could be looking for that doorway in

that's not at the waterfall.

It sounds like I need to refocus

away from the waterfall

and find another way in to get underneath it.

‐ Coriaso always thought

the treasure was under the waterfall.

The strange thing about it is

is we never dug under the waterfall.

He never had us dig there.

‐ 20 years ago,

Rick was part of a treasure hunting expedition

on this same mountain,

led by retired Philippine military officer

Colonel Coriaso.

‐ Coriaso had a map.

The map was the key to the whole thing.

‐ A trusted confidante of Marcos,

Coriaso allegedly was given a treasure map.

‐ We dug down from the waterfall

and way over to the right

on that hillside that drops into the valley.

That's where we were digging.

What I remember is the... came along,

and then the waterfall dropped off.

Okay. Now we've got the‐‐

There's a ridge that kind of comes down

at this angle over here,

and off that hillside

way down here...

that's where we were digging.

There was something significant

on Coriaso's map.

This is where he had us digging.

‐ Inspired by the Curtis tapes

and by Rick's memories,

John sends tech experts Max and Colin

to scan the hillside,

looking for a new way into the waterfall.

‐ So Max and I have the magnetometer.

We're gonna do a grid pattern over this area

that John and Rick have identified.

‐ They're looking for metal that could be a sign

of either treasure or tunnel building,

but the area they're investigating

is over 600 acres.

Locating a tunnel entrance here

won't be easy.

‐ Wherever we are,

it seems like we're in the middle of nowhere

walking over cliffs and through trees

and branches in the face and raining on you.

We're definitely pushing the boundaries

of what our equipment is able to handle.

‐ It's just a slow process, but it's got to be methodical,

and we've got to just map out this mountain as best we can

and find any anomalies that would help John

on his goal to find the treasure.

‐ Back at basecamp,

historian Craig Gottlieb arrives on the mountain

to help decode the mystery behind a recent find.

‐ I'm a military artifact dealer, a historian,

and I was a Marine for 12 years.

I focus primarily on military weapons

'cause, for me, history's really important

and military weapons are a way to jump off and study history.

‐ When exploring the tunnel with the rover,

the team discovered an abandoned knife

200 feet inside.

‐ Looks like my Ka‐Bar.

Ka‐Bar is a military style fighting knife.

They've been used all the way back in World War II.

They're standard issue in the Marine Corps.

‐ They're hoping to get answers

on who left this knife behind

and when.

‐ We really appreciate you coming out here,

trekking all this way.

We really got something special to show you.

It's, it's not gold,

but to us it's definitely a treasure.

‐ So what are you seeing, Craig?

‐ Well, I'm seeing a really old rusty knife here,

but there's more to the story.

Tell me what you know about this

and where you found it.

‐ I found this inside of the tunnel.

It was in an area where there was part of a collapse.

It looks like my Ka‐Bar that I carry.

I have it, actually, with me right here.

‐ You make a good point. It looks like a Ka‐Bar,

but it's not.

And this is, without a doubt, an American knife.

This is a pilot's survival knife.

‐ John: Wow.

‐ People call this knife a mini‐Ka‐Bar,

and for good reason. It's just smaller.

This was designed specifically,

for two purposes‐‐

to be a survival knife

when a pilot went down and crashed.

‐ ‐ ‐ But it was also designed

to be used as an extrication tool

a pilot could use to get out of the cockpit.

Um, so you have this clip point here,

which a pilot could use

to stab a hole into the fuselage.

‐ ‐ ‐ And then something different

that you don't see on the Ka‐Bar‐‐

um, you've got a sawtooth edge here on the back, okay?

So what that could be used for,

it could be used to cut out of the fuselage

after the pilot's made that point inside the fuselage.

‐ My question is, who left this there?

You know, was this picked up by a Japanese soldier

as a souvenir or as a tool

that they found in the battlefield,

or was there a POW?

I mean, this is something

that you wouldn't normally leave behind.

‐ You certainly wouldn't drop it and lose it.

‐ No, it's your livelihood, you know,

when you're out in the field.

You drop your knife or your rifle,

that's one of the last things you want to lose.

‐ Um, I'm not entirely sure yet how it got there.

The good news is is that there were three companies

that made a knife like this,

and if we take a closer look,

we may be able to pin down

exactly when this knife was made,

which we'll tell you maybe not who carried it

but when it was left in the tunnel.

‐ I mean, it's crazy to think‐‐

the possibilities of this knife,

where it's been, who carried it,

how it ended up in this tunnel.

I got to know what it is. ‐ Yeah.

I'm starting to see something there.

Okay. There we go.

‐ What are... ‐ Okay.

And you've got some letters, which is great.

‐ I'm gonna use my loop.

All right.

Now I see it.

Camillus.

This knife was made by Camillus,

which was the government contractor.

I can see the "U. S."

and a little baby bit of the "New York."

‐ So do you know when they were starting

to do the government contract with this?

‐ I do. At very minimum,

this knife was manufactured in 1961,

but it could have been made in '71.

It could have been made in '81.

But at very minimum, '61 or beyond.

It's a jet pilot survival knife.

And we know that it's been in your tunnel

a very long time. Why? Because of the pitting.

This is old pitting. This is not recent age.

‐ When I first seen this knife,

I thought it was World War II era.

It was pretty disheartening to me

to hear that it was from a different time frame.

‐ What we don't know is who dropped it.

What I'd really like to find out

is more about the tunnel itself.

Why? Because, getting that information

alongside the actual age to the weapon,

that would give me a real indication

of sort of the other side of that date range.

But going down the tunnel and taking a look

really helps solidify that educated guess.

‐ We can grab some lights and some hard hats.

We can head on down there

and show you where we found it at.

‐ That would be great.

‐ With the entrance now secured,

the team can safely enter the tunnel.

‐ This is the spot. This is where we made it.

So out knife was about right here, Levi?

‐ Yep. The blade was actually‐‐ when we found it,

it looked somewhat like this here.

‐ You say that the, blade was in the dirt

and the handle was exposed?

Well, there's pitting everywhere,

but there's more pitting on the handle

than there is on the blade.

As you start to look at the bigger picture,

it's easy to say

this knife has been down here for 40 or 50 years,

and that puts it 1970's, 1980's, maybe.

‐ We're looking at treasure hunters again

in that time frame.

‐ That's what I'm starting to wonder‐‐

if it wasn't treasure hunters, you know?

He identified this knife to be from the '70s or '80s.

If it was '70s or '80s, the chances are

that there has been treasure hunters in here.

The bend that's in it,

it's bent like somebody stuck it in there

and possibly pried on it.

Maybe they had a box of gold

or something they found here.

They beat it in there,

and bent it, pried it over,

grabbed the gold,

and ran and forgot their knife.

‐ If a treasure hunter dropped this knife,

it means that they were thinking

the same thing you're thinking.

‐ We're not the first ones that have been here.

Somebody else was on to the same thing we're on.

So the big question here is, who did this belong to?

I think the only way we're gonna find out

is by getting to the end of this tunnel

and seeing who else was here,

thinking there was treasure here at one point.

Did they find something?

Did they beat us to the treasure?

Chances are that there has been treasure hunters in here.

‐ Dating the knife raises even more questions

about the tunnel,

including who actually built it.

To find answers, Rick heads south of the mountain

to a site near the province of Bamban.

‐ I'm not sure about the tunnel that we found.

We're not sure if it was built by the Japanese

or if it connects to a network of tunnels or not.

‐ He's meeting with a Philippine historian...

who's researched

a World War II Japanese tunnel system

called the Onishi Tunnels.

‐ Hi, Rhonie. how are you this morning?

‐ Hi, how you doing? ‐ Good to meet you.

‐ Nice to see you. ‐ I've never been

inside of a Japanese army tunnel.

I'm hoping to be able to get a better idea

of how they were constructed,

what the tools were, timbering, that sort of thing.

When we get into the tunnels in our mountain,

we want to be able to do a comparison.

‐ Vice Admiral Takajuro Onishi

is known as the father of Japan's Kamikaze.

As Allied forces advanced in the Pacific Theater,

he unleashed the first squadron of Kamikaze pilots

in the battle of Leyte Gulf.

Over 2,800 Japanese pilots crashed their planes,

killing 4,900 Americans...

In one of the deadliest naval battles in history.

When Japan finally surrendered,

Onishi committed ritual suicide

in these tunnels.

‐ Here we are. ‐ Wow! Wow, wow, wow!

‐ The famous Onishi Tunnel.

‐ Look at how this opens up right here.

‐ Ooh, yeah! It's a typical Japanese tunnel.

‐ It opens up. It opens up.

‐ Yeah.

‐ Here's a photo. You could see here the wooden brace.

‐ Look at that. ‐ Yeah.

‐ They've got an angled timber in there.

‐ Yep. These are supposed to be angled.

‐ So up here like this. ‐ Brace.

‐ And then an angled piece and one across the top...

‐ Right. ‐ ...and back down.

This looks a lot like what I can see in our tunnel.

‐ Really? ‐ The wood,

the wood framing, yes.

The Japanese really were masters at this.

This has endured over the years of the war bombing

and still intact. Looks perfect.

If we've got the same sort of engineering in our tunnel,

it would absolutely prove that it's Japanese.

Like this one, it probably goes way back in the mountain

and ties into a whole system of tunnels.

What an ideal place to hide treasure.

‐ Deep in the Philippine mountains,

based on a new clue in the Bob Curtis tapes,

Max and Colin continue searching

for any evidence of a manmade tunnel

leading to the waterfall site.

‐ There's something right here. ‐ Okay.

‐ You wanna come and check it out?

I'm pretty sure it's right‐‐right...

‐ Yeah. ‐ ...on this little mound here.

Should I flag it?

‐ Definitely.

‐ Max and Colin alert John and Rob about their find.

‐ So find some cool stuff?

‐ Yeah. Got a hit over by these rocks.

‐ Very cool. ‐ Okay.

‐ So, let's just dig it up

and see what it is. ‐ All right.

‐ They're looking for metal,

which could mean either treasure or a tunnel site.

‐ I'm ready.

‐ I would say it's deeper down, for sure.

‐ We're still getting a reading,

but down pretty deep. What do you think?

‐ That's a good sign. If it's deep, you know,

that's a very good sign.

I'm thinking there's probably a pretty decent target

maybe down there. ‐ You want to check it again?

‐ Yep.

‐ Still consistent.

‐ It's that signal identical.

‐ Signal's not low enough yet,

but it's relatively consistent going down.

‐ What do you want to do?

‐ Desperate to find the tunnel, John takes a gamble.

‐ I really want to see what's in the bottom here.

Maybe it's time to get a bet‐‐ the excavator up here

and just dig this damn thing out.

The next day,

head researcher Bingo Minerva updates the team

with new information

regarding how much treasure may still be in the mountains.

‐ Hello, Bingo. How are ya?

‐ I'm doing good, guys. How you doing today?

‐ We're good.

‐ So I've been working

with military historian PJ Springer.

Now, he had a lot of evidence

that he got from the National Archives

that show what the Japanese were looting

and, not only that, how much of it they looted.

‐ For the purposes of your team,

if we're talking about the northeastern portion of Luzon,

and in particular Nueva Vizcaya,

that's the last place

that the Japanese are getting pushed into

when Yamashita finally surrenders.

If there's a huge treasure trove,

it's going to be in the last places

that were under Yamashita's control.

‐ Do you know the total value of treasure

that the Japanese took and looted?

‐ You're talking hundreds of billions of dollars

unaccounted for. ‐ Wow.

‐ My conservative estimate is

maybe 20% of it has been recovered.

‐ What happened to the other 80%?

‐ An awful lot of it is just a complete mystery.

‐ Announcer: According to Bingo's research,

the treasure on the mountain might be more than just gold.

‐ Bingo: Really exciting stuff.

I mean, I've got a number of pictures here.

I think this is one of the cooler pictures.

These are little canisters full of diamonds.

I mean, there were so many of them

that they didn't even count it.

They measured it by weight of the carat

that they had in them.

‐ Show me pictures of treasure, man,

and my blood starts to boil.

I want to start digging a hole like a gopher.

‐ One of the main things they had were these coins.

I don't know if you can see that there,

but a lot of it was stored

in, like, burlap sacks and crates.

‐ You know, there's a very‐‐

really good possibility, like at Breach 6

where they just picked up, like, metal hits or iron hits.

There's just an endless possibility

of what could be in there.

There could be diamonds, gems.

I mean, the list goes on and on.

‐ Announcer: Recent NMR scans

conducted by the team over Breach 6

indicate a large cache of metal

just below the surface.

Hoping the hits are metal canisters,

Rick returns to the site.

‐ I've been chasing this treasure

for almost 20 years.

When I was here 20 years ago, the Pyramid Rock was here.

There was no Breach 6.

Nobody had dug a hole in the ground.

‐ But according to Rick,

during the time he worked with Colonel Coriaso,

the Colonel was interested in this area

as well as the waterfall.

‐ Rick: Coriaso had a map with him,

and, you know, he wasn't sharing it with anybody.

He was keeping it really secretive.

I got to see it one time, just a glimpse.

It kinda showed where a pyramid was,

and there was a lot of Japanese writing on it.

He kept saying, you know, "That's‐‐

That's where we want to dig. That's where we want to dig."

I'm not sure if they kept going with, once I was gone.

‐ Rick suspects the existence of the hole known as Breach 6

indicates Coriaso and his men returned to the site

to excavate it.

But whether Coriaso reached the treasure is unknown.

For decades, dark stories have surfaced

about a team of treasure hunters digging here.

And the area still has dangers.

‐ Rick: We've got the Pyramid Rock.

We've got this tree, roots hanging out.

We've got a boulder about to come down.

We've got this undercut over here.

‐ Steve: Wow.

This site's a lot more dangerous than I thought.

‐ Before proceeding further,

Rick wants to better understand the lay of the land.

‐ There's a lot going on here.

We need to get the tech team over here...

and have them help establish

a pinpoint‐accurate place to dig.

‐ Yes! In this situation,

it's too dangerous to walk into the Breach 6.

The area is very unstable.

We're not comfortable going in there,

so we're gonna fly our drone with the magnetometer,

and that provides a perfect solution

to get in there safely

and still collect very high‐quality data.

You got a couple meters still, Colin.

‐ Later that day, back at basecamp,

Max and Colin show Rick their findings

from the magnetometer scans.

‐ How you doing?

‐ So here's the Breach 6 data.

We went in this whole area.

There's these three anomalies that we think are interesting.

‐ So at this point, we're here, here, and here.

‐ Yeah. ‐ We've got the satellite scan,

and it runs right over that same line.

So, I mean, all of these things

kind of start stacking up. ‐ Right.

‐ You know, I really think

that there's a tunnel running along that line.

Um, I think we've got enough information.

We should dig. And I think we should dig right there

next to the larger anomaly.

I think this ferrous line is the key to the puzzle.

‐ So we're on top of something.

‐ Rick: We're on top of something.

Definitely on top of something.

‐ The biggest target they got,

that's where we're gonna go, right here.

We need to start digging.

20 years I've been waiting for this. This is awesome.

‐ Steve: I'm gonna take your stake out. Here it goes.

‐ We don't know exactly what's down there.

We don't know what kind of metal it is.

The metal readings could be iron boxes full of gold.

This could be a tunnel. It could be a room.

It could be artifacts, could be machine guns,

could be tanks for all I know.

But until we get to the bottom,

we're just not gonna know.

‐ But not far into the excavation,

Steve runs into a major problem.

‐ How's that ground so far? Is it holding up?

‐ Not at all.

This is the crappiest stuff I've ever dug in.

‐ Yeah, it's kinda what it looks like from my side, too.

I don't know how much we're gonna be able to step this down.

It looks like it's just gonna fall in on you.

‐ The soil around the dig site is too unstable to dig deeper.

‐ It's not gonna hold up.

‐ So we still gotta be careful as we're going down.

Get it as good as you can.

‐ If Rick has any shot at reaching the metal target,

he'll need to figure out a safer way in.

‐ It feels like me against the mountain,

just frustrating.

‐ With the Breach 6 dig on hold,

the team to pivots.

Days earlier, the tech team found a possible clue

as they searched for an alternate way

into the waterfall.

‐ There's something right here.

‐ I would say it's deeper down.

‐ Though it's not much to go on,

John gambles on exploring it,

hoping it will be a tunnel leading to the waterfall.

‐ I want to see

that the entrance to the tunnel is here.

I want to know what's in there.

I want to get the excavator up here.

All right, Michele, come right on at me.

‐ John's brother Rob and Michele are tasked

with getting the team's other excavator to the new dig site.

‐ Without getting this excavator to that site,

we don't stand a chance in recovering it.

We have to make this road,

and we have to get to the site.

‐ It's not easy to get an excavator of this size

through terrain like this,

so she's basically just taking the higher part of the hill

and moving it down to the lower

so that we can continue to move forward

without falling down it.

There's so many variables.

There are so many things that can go wrong.

This is extremely difficult.

‐ Just as Michele and Rob start making progress...

‐ Michele: Whoa! ‐ Rob: Wait. Wait.

‐ ...the excavator hits soft ground,

causing the right track to sink into the mud.

‐ We are deeply.

All right, hold it. Rotate it right

and then reverse your left track.

God, you're kidding me.

Every move you make

is putting that track even lower in that hole.

‐ I'm as far as I can go.

‐ Now it's pouring rain on us.

If this machine tips over, it will be catastrophic.

Yeah, we're in deep.

‐ My goodness. Wow.

‐ I'm getting soaked.

The biggest problem we've had is how much rain we have here

and how muddy it gets.

Just everything about the weather here at this mountain

is our worst enemy.

‐ I feel defeated.

‐ As dawn breaks over Breach 6,

Rick's found a new way to dig.

He hopes to access a line of possible metal,

identified by NMR scans here,

aligned just below the surface.

‐ How's that ground so far? Is it holding up?

‐ Using the excavator here doesn't work,

so Rick's come up with a human solution.

‐ Nice job.

‐ Got your studs right here, man.

‐ Rick's called in miners Brent Lister and John Farrell

to build a reinforced steel shaft

that will safely allow the team

to access the metal targets under Breach 6.

‐ The idea of what we're doing here is

we're gonna go in with steel sets, dig a shift.

These sets are gonna keep us as safe as possible.

There's no way this job will be easy.

From what I can see, it's gonna be really soft clay.

It's gonna be very hard to hold that ground above us.

As the deeper we go, the more the danger will rise.

You got a spot up there where there's nothing?

Well, first time in Breach 6. We don't know what's down there.

I mean, that's what I'm here for‐‐

to dig a big hole

and figure out what's down in the bottom of it.

‐ As Brent and Farrell prepare the shaft,

they find something unusual.

‐ What is that?

‐ What does it look like to you?

Does it look like a big hard rock

or a big hard chunk of concrete?

What do you think that is?

‐ Like some Portland cement?

‐ Well, like, all this might be like Portland cement,

but then this would be like the small aggregate

they would've used, like, crushed rock.

‐ Aggregate is the filler material

used when making concrete.

It typically consists of small crushed rock,

coral, or seashells.

If it is aggregate, then that would indicate

that the hard rock is, in fact, manmade concrete.

‐ Dude, that's just weird

how that rock's like that, though.

‐ But is it rock?

‐ Hey, Rick, this is Brent. You around?

‐ Rick here.

‐ Hey, Rick, we, we dug down to something real hard.

It's like a slab all the way from wall to wall.

‐ Whoa, whoa, whoa, Brent.

Hold on, hold on.

Let me get down there and take a look at that thing

before we start, banging on it.

‐ This concrete slab,

you know, it worries me a little bit.

We don't know what's underneath it.

‐ Announcer: In the Philippine mountains...

Rob and Michele return to the excavator,

hoping to dislodge it from the mud.

‐ Rob: She's really in there.

Let's get started.

‐ We have to get it out of this pit,

or we don't stand a chance

of getting into that waterfall.

I think our best bet is gonna have to do this

in little steps

that tilt that way but rides up.

I don't see any other way of doing it, really.

Okay, Michele, behind you,

you are, like, right on the edge of this pile of dirt.

You're really scaring me right now.

‐ I'm starting to wiggle my way out of this mess.

‐ Looking good. Keep moving.

Come on.

Right there is good.

Ease up.

‐ Thank God.

I didn't think we were ever gonna get out of this mess,

I'll tell you.

‐ As Rob and Michele claw their way up the mountain...

digging continues towards the metal deposit

detected beneath Breach 6,

where miners Brent and Farrell

have made a puzzling discovery.

‐ What is that?

‐ What does it look like to you?

Does it look like a big, hard rock

or a big, hard chunk of concrete?

‐ Rick has come down

to examine why the concrete is here

and what it could mean.

‐ I don't know what it is. It is‐‐

It's wall‐to‐wall hard all the way.

‐ Could be just like concrete.

‐ It sure could, yeah.

Well, we're looking down at a possible cement slab

in Breach 6.

‐ Concrete is a signature of Japanese army construction.

On islands like Iwo Jima,

the Japanese used a unique cement mix

to build an 11‐mile network

of tunnels and underground bunkers

to protect them

from the impending American invasion.

The discovery of similar concrete here

could mean they are on track

to intersect a Japanese tunnel.

‐ All right. Here goes nothing, man.

‐ Rick: I am hoping this is concrete.

I've been listening to these Bob Curtis tapes.

In the shafts Bob Curtis was digging,

they found concrete.

‐ It's pretty hard right there.

‐ Is it? ‐ Yeah, right here

in this corner, it's real hard.

‐ Ultimately we're trying to get to the treasure.

Hopefully this is the access point.

Is this is concrete,

it's a pretty good chance it's a cap over a tunnel.

Right now I'm the most excited I've been.

I think we're the closest

to finding another way into the mountain.

‐ On the next "Lost Gold of World War II"...

‐ What is that?

‐ It could possibly be nitroglycerine.

And it is highly, highly volatile.

You drop a rock on it, it'll blow up.

‐ If there's explosives in this tunnel,

this dog will find it.

‐ 'Cause this thing could be booby trapped

from the front to back,

and y'all have just been lucky so far.

‐ Who's going?

‐ So you're saying he's brought you

actual Yamashita treasure maps.

‐ It felt to me like he was running for his life,

that someone could kill him.

‐ Rob: What's happening, Michele?

‐ I've run into bedrock.

I can't dig any deeper.

‐ If she's hitting bedrock right now,

we're not gonna get through it this way.

Captioned by Los Angeles Distribution and Broadcasting, Inc.