Episode 2 Steve Backshall's Extreme Mountain Challenge

These are the Tepuis of Venezuela...

..ancient towers of rock...

..isolated refuges for rare plants and animals...

..lost worlds,

cut off by sheer-sided cliffs from the jungle below.

'My name is Steve Backshall.'

Come on!

'I'm a naturalist and adventurer.'

Oh, wow!

'And to me, nowhere says adventure more than this place.'

'So I'm leading a team of top climbers,

'expedition professionals, and film-makers,

'on a month long expedition to explore these islands in the sky.'

Wow!

'To search for wild life...'

Monster!

'..and to understand how they were formed.

'We're going inside a Tepui to explore a vast, unchartered cave.'

I don't like this at all.

'And taking an abseil alongside the highest waterfall in the world.'

Whoa, that is out of this world!

But at the end of week two,

we still haven't completed our first objective -

to climb an unclimbed Tepui and explore its summit.

'We've spent four days tackling this monster cliff face.'

Oh!

Oh, it's really hard!

'And now we're running out of time.'

HE BREATHES HEAVILY

Day five of the climb and we wake on a precarious ledge,

halfway up the mountain.

What a difference a day makes.

It's the first time we've woken up, we've not been inside a cloud.

I can actually see the mountains and blue sky.

What do you reckon? Do you think our luck's changing?

Fingers crossed.

It would be nice after yesterday, wouldn't it?

The previous day, our attempt to become

the first people to climb this vertical rock face

almost ended in disaster.

The birds are all coming into roost.

There's a big storm coming and they know it.

What a storm.

It left us clinging to the cliff, and then came the rock fall.

No, no, no, no!

Head, head!

We've got to get off this thing. Someone's going to die.

'You could taste the fear.'

-It's just really dangerous, isn't it, up here?

-Phew.

It's only a mountain, you know, nothing is worth risking this for.

I'll tell you what, after yesterday I was...

I was all about just getting the hell off this mountain,

but now I kind of feel we should keep going. What about you?

-Yeah.

-You do?

-Yeah, give it a bash.

Well, we've come an awful long way.

It would be a shame to give up so easy.

Time to make one last attempt to get to the top.

The climbers set off from the ledge to establish a route.

Brit John Arran, and Venezuelan Ivan Calderon,

are amongst the world's best Tepui climbers.

Meanwhile, halfway up the cliff face,

team medic Aldo Kane and support climber Fuko Pisani

construct a quarter ledge camp in preparation for the night ahead.

Whilst below, cameraman Keith Partridge and I wait on the ledge

ready to follow up the cliff face,

once the climbers reach a safe position.

But this waiting game doesn't suit me.

Too much time to brood on potential disaster.

We've now been on this thing for five days.

That was supposed to be how long we would take to summit, and we're

only a little way past halfway,

so John and Ivan have pushed on ahead.

They're trying to cover some serious distance without me

slowing them down, and without the camera slowing them down,

and I really hope that they're safe up there.

But the omens aren't good.

'Another rock fall.'

Aldo, are you OK?

Aldo?

Keith to Aldo, do you read? Over.

'Aldo. Send.'

OK. No, just huge lumps of rock came down.

Just making sure you're all OK up there.

'Yeah, I'm not sure where that came from. Over.'

High above, John and Ivan are actually making good progress.

Then, around mid-day, they hit a problem.

Blocking their way is a band, or strata, of rock

that looks close to un-climbable.

What do you think, Ivan?

Usually, the quartzite sandstone

that makes up these cliffs is bullet-hard,

but this band is different, heavily fractured.

Ivan decides to keep going.

There's no alternative if we're going to make the summit,

but it's a gamble.

He's climbing at the very limit.

Sitting on my ledge, I'm unaware of

the intensifying drama 100 metres above me.

Until...

YELLING

I think that might be us.

Just quickly, just check.

'Steve, this is John, over.'

John, go ahead.

'Hi, Steve. We've had a bit of an incident up here.

'Ivan took a big fall, about a 50 foot fall.

'I got slammed into the rocks,

'and I've got a fairly nasty cut on my chin and lower lip. Over.'

Our cameras just missed Ivan's massive fall.

Here he is moments later climbing back up the anchor rope,

and this is where he fell from.

Incredibly, Ivan isn't really hurt at all.

John, what do you think? Over.

'Well, we certainly can't go the way we just tried,

'and that looked to be the easiest way.

'The only other alternative would be

'a fairly severe traverse left and right

'but it would take four or five days. Over.'

'But we don't have supplies for another four or five days.

'It's time to face reality.'

The Tepui has defeated us.

That sounds like decision time, to me.

First of all you need to get back down to here so Aldo can treat you,

possibly put some stitches in you, and secondly, we retreat.

That's it, then.

This is as high as we get.

Our climb is over.

John and Ivan retreat to where

expedition medic Aldo is waiting below.

Worst nightmare, really.

Un-climbable rock, effectively.

Never seen that on a Tepui before.

Not the same kind, anyway.

Just about ten metres of completely green, shattered rock.

So what happened with Ivan?

He was trying to head through this.

He was putting little pegs in,

and he was getting further and further away,

and eventually something just ripped,

-and every single piece he put in...

-Every single bit!

..all just went ping, ping, ping, ping.

Big block came straight out.

-How far do you think he fell?

-About 50 feet.

Went straight down onto... onto the anchor.

Thankfully we had a good anchor in.

-But he's not injured? He hasn't...

-He's not injured at all.

He's got tiny cuts on his... on his hand, but it's nothing.

-Sounds like that was incredibly lucky.

-Yeah.

I'm desperate to find out how the boys are,

so I climb the fixed rope as quick as I can.

-Are you all right, mate, are you OK?

-Yeah, yeah, I... I'm OK.

That... that is a big, big fall to take.

Yeah, yeah, it was scary but every...

everything happened so fast.

It's a rush of adrenaline, so you... After the fall,

you feel like really, really light, you know, like, "Phew",

I don't say... I don't know if, if, if I can say that,

but it's like an orgasm, yeah.

It's like an orgasm?

Yeah, something like that.

Mate, you're doing one of those things wrong.

I'm not sure what it is.

No, but I think we took the right decision,

-because I think...

-It's the only decision.

-It is the only decision.

-Yeah.

We all hate to be beaten.

Abandoning the climb feels like a punch in the guts...

..but pushing on further would be madness.

All I can do is put a brave face on it.

I have to say, being here in this extraordinary,

almost otherworldly light,

with the swifts and the swallows circling around my ears,

it is one of the most extraordinary places I've ever been.

And we know for a fact that we are the first people ever to be here,

so this doesn't feel like failure, far from it.

But I came here to explore the lost world

on the very top of a Tepui, and we can still do that.

That huge looming shape in the background is Auyan Tepui.

It's one of the very biggest,

and on the summit is an environment

that's unlike anywhere else on Earth,

and we can get there without having to climb.

That is just fine by me.

Leaving the climbing team behind, team medic Aldo,

the film crew and I take to the air.

Our destination is the huge Auyan Tepui.

Recently a cave system has been discovered inside the Tepui.

Our objective is to explore this cave...

treading where no-one's been before...

..and shedding new light on how the Tepuis are formed.

But before that, I have unfinished business.

I may not have been able to climb onto the summit of a Tepui,

but I'm still desperate to explore one.

This is actually a much denser,

more developed forest than I was expecting

on the top of this Tepui, and that river is incredible.

Oh, wow!

No way!

HE LAUGHS

Woohoo!

'But I need more than an aerial tour...

'..so the pilot picks out a suitably remote spot

'to give me a few hours to look around.'

I think he's taking us down to the top of the waterfall.

If he tries to land there he's crazy.

Oh, my God. Ha, ha, ha, ha!

I really do feel like I've just

beamed down from a spaceship onto an alien planet.

Look at these totem poles, almost.

I've never seen anything like it.

At last, the summit of a Tepui.

We may have cheated a little to get here,

but I think we've earned it.

I've got a few precious hours to explore,

and hopefully find some of the life that inhabits this strange place.

The elevation and the vertical rock walls

are a really efficient barrier to life,

but clearly plants and animals have found their way up here.

Whether they climb, get dropped or borne on the wind,

very few of them are going to survive.

The hardy few that do, will adapt to the conditions here,

and over millennia, some will turn into new species.

And then they're going to be trapped up here

exactly the same as if they were on islands.

Oh, I've got something!

Lovely.

There's a rather charming little black and white spotted weevil

wandering over this plant.

This one's flightless and I haven't seen them on the savanna below.

It's almost certainly a Tepui-top specialist.

This is one of the reasons why life is so challenging up here.

On the Tepui tops, it can rain as much as nine metres in a year,

and that just washes away all the topsoil,

and all you're left with is sand.

These Tepui tops are sometimes known as being rain deserts,

and so the plants have to find other ways of gaining nutrients.

And a short while later, I find a particularly unusual example

of how those nutrients can be produced.

Look at that. Beauty!

This is the Tepui tree frog.

It's only found on the summits of mountains like this.

Though it's very similar in form

to all the other tree frogs found in the tropics,

this one here lives inside these plants. They're called Brocchinia.

The leaves are clasped together into a vase,

and water collects inside them.

They will function a little bit like a pitcher plant, and catch insects,

but they also gain nutrients from these tiny frogs.

The frogs will sit here on the rim catching insect prey,

and then as the frogs excrete waste material,

it drops down into the plant and helps them to grow.

So there's kind of a symbiosis,

a mutual relationship going on between the frog and the plant.

There's never enough time for a place like this.

I've barely scratched the surface.

But these few short hours

have made me even more curious about how the Tepuis are formed.

For now that's going to have to wait.

The cave beckons.

And for that we'll need the help of a specialist caving team.

THUNDER RUMBLES

Does that sound like thunder?

Yeah, thunder, yes.

So we have a storm coming in.

Our expedition has been plagued by the early arrival of the rains.

That is proper rain.

The only escape is inside the tents.

But things could be worse.

The caving team are Italian,

and they're in charge of catering.

Look at this!

At least we're in the right tent where someone's cooking.

I don't eat this well at home!

-So we have some good vino to go with this?

-Yeah.

Maybe a nice Chianti?

ALL: Sangiovese!

Don't be ridiculous!

-From Italy.

-I love travelling with Italians!

To celebrate the new exploration!

What are we celebrating? We're sat in a tent in the pouring rain.

We are here on the Tepui!

This wine-loving Italian is Francesco Saro.

When he's not sipping the good stuff,

he's the expedition leader,

and the man who discovered the cave.

It's a beautiful place. Outside, now, it's a bit hard but...

Someone teach these guys how to open a bottle of wine!

ALL: Hooray!

When we wake up, it's actually dry for a change,

and we're not the only ones enjoying the sun.

We have ourselves a visitor.

It's a possum.

It's got a long naked, almost rodent-like tail,

white face with dark markings but actually it's a marsupial,

believe it or not. It does raise its young in a pouch,

and it's been going round the outside of our tent.

That's surprisingly bold, considering we're all here,

all making loads of noise,

but I guess any food is going to be really welcome.

I really didn't expect to see any mammals on top of Auyan Tepui,

I have to admit. This is a very, very nice surprise

and actually quite a treat.

Time to go caving,

which is just as well because the weather's closing in again.

It's an atmospheric descent through the mist,

into an enormous ravine filled with colossal boulders.

Until recently, no-one was looking for caves inside Tepuis.

It's the wrong kind of rock,

which made Francesco's discovery all the more exciting.

It was this dramatic gorge that led him to the cave.

-We were searching for collapses.

-Yeah.

-It means that there is a void.

-Uh-huh.

And then we were studying satellite images,

and we found this one, which was very big,

-you can see it's a huge collapse.

-Yeah.

-Can form only if there is a cave below.

-Uh-huh.

The cave Francesco and his team discovered is vast.

How big, no-one yet knows.

So far they've found over 20km of passage,

but our job is to push even deeper into the cave.

It's more than just exploration, though.

Going inside a Tepui gives us the chance to understand what

makes them such spectacular and unusually-shaped mountains.

Now be careful here.

We are entering in between the boulders.

-Down there?

-Yes.

You'll be fine if you can hear the river.

So you can hear the water moving below you?

Yeah. Yeah, absolutely.

'No more rain but instead we've got an underground river.

'Looks like we're going to be staying wet, then.'

Bye-bye, light.

'Making our way into the cave over treacherously loose rocks,

'this isn't a place to lose concentration.

'as Keith, our cameraman, learns the hard way.'

Oh, Jesus, KP, are you all right?

Yeah.

How are your hands?

Little minor graze.

Just trying to protect the camera, that was all. Let's go.

'If that's the worst the cave can throw at us,

'we'll be getting off very lightly.'

'Deeper into the cave, and I'm beginning to appreciate

'what an astonishing place it is.'

That's incredibly beautiful.

Gypsum crystals.

'This is our new home.

'We're going to establish a base camp,

'and spend three full days deep within the Tepui.'

'Although our main goal is to push into unexplored areas,

'I also want to search for life.'

'This cave is millions of years old...

'..so some of the animals down here have had plenty of time

'to evolve into new species.'

'It's just a case of finding them.'

It's a cricket...

..that lives in the water and swims.

And jumps, just like a normal cricket!

This is one of the top predators inside this cave system.

They are carnivorous. They feed on other insects,

tapping around in the dark with those great long antennae,

searching for food to prey upon.

This one's a female.

You can see that scimitar-shaped ovipositor, or egg laying tube,

at the back of the abdomen there,

which she uses for laying her eggs.

But most extraordinary,

they're most comfortable in and under the water. They're aquatic.

These are known from several other Tepuis tops,

but they've probably been separated from each other

for hundreds of thousands, if not millions of years.

So it is entirely possible that this one here

is found only in this cave system.

that this species could be unique to Auyan Tepui and its caves.

Knowing my interest in wildlife,

Francesco has a surprise in store.

An ancient mystery that he's hoping I can help solve.

So fragile here.

Oh, wow.

Wow, that's incredible.

This is... This is extraordinary.

-I don't really know what to say.

-What do you think?

I don't want to jump to any conclusions but,

it looks like something that absolutely shouldn't be here.

OK, so... what we've obviously got...

Let's stick to the obvious first.

It's a medium-sized mammal,

almost certainly a carnivore.

Well, no, certainly a carnivore.

The way that it's lying here,

it just looks like it's laid down and died here but,

-but you can see all, like, tiny like shiny crystals on it.

-Yes.

-So what does that mean?

-It's silica crystals.

-So they formed on the bones?

-That's right.

Can you guess how old this might be?

In my opinion, to get so much silica on the crystals,

it has to be some thousands,

tens of thousands of years.

OK, well, that's pretty extraordinary!

One of the best ways of

finding out things about mammals is their dentition, their teeth.

And we've got there the remnants of carnassial teeth.

Those are big cheek teeth that are found here,

and those are used for slicing up meat.

This... It's a cat, this is a cat.

It's much too small for... for puma or jaguar, obviously.

It's too big for margay or jaguarundi.

It looks like an ocelot.

That's incredible!

This would be the first ever record

of any kind of wild cat found on the top of a Tepui, ever.

Which is mind-blowing.

But it's perhaps even more mind-blowing,

that this could have been here for thousands of years.

Almost certainly it has.

Before we get back to our camp, there's another weird sight.

In fact, if anything, it's a bit unsettling.

This is the lake.

What causes all the colours?

Bacterial colonies in the water.

At least 40% of the bacteria living here

are unknown species for science.

So what kind of things have you been finding here?

For example, bacteria which are very close to species like the one

housing the bubonic plague.

-The bubonic plague?

-Yes.

You never told me that beforehand!

Yeah, because probably they are similar

but they are not aggressive to humans.

We hope.

Hopefully.

Settling down for our first night underground,

it's the plague that's on everyone's mind.

Who's pinched my cup?

See, nothing's safe around here, is it?

-Well, we've all got the plague, so it doesn't matter.

-Exactly.

THEY LAUGH

'I'm more worried by something a bit more tangible.'

Last thing you want sand in your sleeping bag.

'But it isn't dry sand or the plague that's the problem.'

'Aldo's the first to realise something's wrong.

'He's woken by the sound of rushing water.'

Well, basically, where we are sleeping, it's running fast.

Pretty scary, that noise.

It's obviously been hammering it down.

It just goes to show how quickly this environment can go from

almost benign to, to deadly, really.

If it does get any worse,

we need to make our way up on to this high ground.

It turns out we're in luck.

The water level peaks soon after.

We'll just have to take turns through the night,

keep an eye on it, listen out for the noise.

'Dropping off, I expect to be woken by water lapping round my ears.'

'When I wake, I'm still knackered.'

Just ten more minutes.

'Who says it's morning anyway?

'Hard to tell when you're in perpetual darkness.'

Oh, I just love putting the cold, wet cave suit back on again.

Urgh, soggy for the rest of the day. Hooray.

'Day two, and there's one question that needs sorting out.

'How were these caves formed?'

'Tepuis are made from quartzite sandstone,

'and that's one of the hardest rocks on earth.

'Caves just don't belong here.'

'But Francesco is a geologist,

'and he's been working on an answer to the mystery.'

'It begins with the strange pillars that line these galleries.'

'You'd think the water did its work of erosion

'by just wearing down the rock.

'But Francesco thinks not.'

Yeah.

Wow.

'The water isn't wearing the rock away,

'it's dissolving the bonds that give the rock its strength.

'It's a chemical process that gradually turns hard sandstone

'back into sand.

'Effectively, the Tepui is rotting from within.'

'Over millions of years,

'this hollows out vast galleries,

'and leaves behind these ever-dwindling columns.'

What happens when that finally goes?

-So you just get a huge, huge fall?

-Yeah.

And is that an important process for the Tepuis?

-Oh, OK, so it's not just forming inside the caves.

-No.

But the whole Tepui.

The distinctive summits of the Tepuis are cut with deep gorges,

that have been shaped by the collapse of these underground caves.

There are even places where you can see the remains of cave systems,

exposed on the surface.

But the influence of water rotting the rock

also shapes the Tepuis in another way.

The big vertical rock walls that you get on Tepuis,

are they related to this?

The tops of the Tepuis are littered with deep vertical fractures.

As water percolates into these cracks,

it rots the sandstone,

just as it does in the cave.

Over time the cracks get bigger,

until the rock falls away.

Leaving behind huge cliffs.

After the repeated soaking we've had throughout the trip,

perhaps it shouldn't be a surprise that water is responsible

for creating these huge isolated peaks.

'But it is surprising that only underground

'do you get to see how the process works.'

'Our final night in the cave.

'Tomorrow will be a step into the unknown.'

'We're going to try and break through

'into a previously unexplored area of the cave.'

You can feel there's a whole different attitude

around the camp this evening.

A kind of sense of anticipation and excitement,

and it's that not knowing what's ahead.

The idea of going somewhere that no-one's ever been before

is a very powerful one.

Very, very exciting.

But also daunting.

Who knows what we'll find?

'Our final day,

'and we tramp down familiar passages following one particular lead.'

'The cavers had previously encountered a collapse

'at the far reaches of the system,

'and believe that there might be

'a whole new section of unexplored cave on the other side of it.'

'Leaving the rest of the team behind,

'Aldo, Keith and I join Francesco to investigate.'

You see the gallery here on this collapse.

But I think that behind the collapse the galleries continue.

'This is it.

'If we can get beyond that shattered rock,

'we'll be treading where no human has ever been before.'

'But we're heading into trouble.'

This rock shows how careful you have to be

as you're moving through these passages.

It's pretty big, probably weighs about half a ton,

and it's held in place by a couple of fixtures of sand.

If you put your hand on that the whole thing would come down.

Go careful there, careful.

How does it look down there?

There is a passage but a narrow one.

Just don't touch any of that stuff to your left-hand side.

Don't touch any of it.

This is the... the floor of the cave,

-of the gallery... of the gallery.

-Yeah.

This is a good way, but we have to see if it's open.

What do you think?

We could try to go here.

It's a squeeze.

It's a squeeze but it's worth to try because I can feel some air coming.

'The air coming out of the passage must be coming from somewhere.

'That's the theory anyway.'

This is the bit of caving I don't like.

Squeezes.

I'm not built for this.

I just hope if this doesn't lead anywhere,

I've got enough room to turn around.

I've got it, I think. Yeah, I've got it.

'Mercifully, the passage widens.'

On the other side is a new section of the cave,

that no human has ever set eyes on.

This place has never seen light in 40 or 50 million years

until now.

The whole ceiling's collapsed. We've got our first open amphitheatre.

Absolutely beautiful.

-Here the cave is becoming bigger, so it's worth to make a map.

-OK.

-OK, Steve?

-Yeah.

Can you find a spot there where I can see you?

Maybe there?

OK, here?

'Discovering new areas of the cave isn't just for kicks.'

'Francesco's maps are changing the way we think about the Tepuis.'

'Although they're made from hard rock,

'it's becoming clear they're like a Swiss cheese,

'riddled with passages and caverns.'

'So far, so good.'

'But there's one more unexplored collapse that Francesco thinks

'might link back to the known cave system.'

So now we can have a look down.

Yeah.

This way, because I think that we would

have to arrive to the deepest section of the river.

-OK.

-So this way.

'That matter of fact tone doesn't fool me.'

It's like walking on razor blades!

Yeah, that's peeling off.

You can see the facture line right down here.

-Welcome to the narrow caves.

-Yeah!

How's it looking, Francesco?

Continuing very flat.

Yeah.

Shall we come?

You can, but be careful with the roof!

Don't touch the roof!

OK.

'It's another squeeze,

'but this time littered with scalpel-sharp rocks,

'and a dangerously loose ceiling.'

'Basically all of my worst caving nightmares rolled into one.'

This place has been undisturbed for tens of millions of years.

It seems incredible that just a single nudge could bring down

something big, but it could, so we have to proceed with real caution.

Someone getting trapped underneath one of these big rocks or

a broken arm, or broken leg down here would just be unthinkable.

OK, so everyone, proceed with caution.

Oh, that slab above me looks horrible.

That's really, really loose.

Oh, I don't like this at all.

There's about one foot between the ceiling and the deck,

and it's so loose.

Just slowly, slowly does it.

It's not a very safe place.

You're in a safe place?

-It's not safe.

-It's not safe?

No.

'Well, I'm glad we got THAT clear.'

This is, if I'm honest, pretty desperate.

It's like sliding around on a bed of knives,

hoping the sky doesn't fall in.

All I hope is that we don't hit a dead end,

cos I don't want to come back through this, ever again.

It's all down to Francesco.

Can he find a way through?

OK, it's getting bigger!

Great!

'After several hours of nerve-shredding tension,

'finally we can stand up.'

Don't worry about the rucksack, Aldo, it's a bit of kit.

-Are you all right, buddy?

-Yeah.

That was pretty sketchy, wasn't it?

Did you see the huge chunks that were fresh on top without the dust?

Which means, you know, some of it is probably thousands of years old,

-some of it is probably a few weeks old.

-Yeah, yep.

This is not a nice place to hang about, is it?

-No, let's get out, then.

-Let's get moving.

OK.

'Francesco's instincts haven't let him down.

'We've been spat out into the deepest point

'of the known cave system.'

So we're back at the main river. We've completed a loop.

'Mission accomplished, it's time to follow the river

'and return to the surface.'

'But Francesco keeps hinting there's one last surprise.'

Whoa.

This is beautiful.

My dream is to explore, to go places no-one's been before.

Places like this.

A waterfall tumbling into a cave on the top of a 2,000-metre mountain.

There's not many places on the planet you can see that.

And blue, blue sky above.

We've spent most of the day scrambling around in a passageway

that has never seen light.

Now I guess we have to head back,

but I just want to spend a few more minutes here, enjoying this place.

Amazing.

'What a place to end our cave adventure.'

'It's time to move on to the final stage of our expedition.'

We are leaving the dark world of the caves behind,

and heading to the next spectacular phase of our expedition.

One of the most iconic natural wonders on the planet.

'And I'm looking forward to meeting up with the climbing team again.

'They've been busy preparing a truly spectacular end

'to our Venezuelan adventure.'

-John, how you doing?

-Great, great.

-Good to see you. Hola, hola.

-How was it?

-Yeah, really good, really good.

-So you have something special planned for us?

-Yeah.

We have a great plan. More than grand. It's fantastic.

That's what we like to hear.

'Our final challenge is to get down from the summit of Auyan Tepui.'

'Obviously we could take the chopper,

'but there's a more exciting way.'

'Not only is it going to be breathtaking,

'but it will allow us to see these mountains,

'and their sheer-sided cliffs up close one last time.'

Just making our way towards the edge now.

At the moment it's shrouded in cloud,

but it's a billowing, moving cloud and could clear at any second.

And when it does, I think it's going to be pretty spectacular.

Listen to that noise. It's like a thundering roar.

And I can just see down below, there's a thousand metres,

nearly 3,000 feet below,

a huge carpet of rainforest.

It's clearing, it's clearing!

That is one of the most beautiful things I've ever seen.

This is the Angel Falls.

979 metres - that's nearly a kilometre of cascading water,

tumbling down to the forest beneath.

I don't get any sense of fear over heights normally.

I mean, you couldn't be a mountaineer and get vertigo,

but seriously, looking over that edge is just gut-wrenching.

Puts your stomach in the back of your mouth.

This expedition has been dominated by water.

The clouds circling around our ears,

the constant battering of rain, following the river right

through the inside of the Tepui and now finally, we're going to

follow that water as it cascades over the edge of the mountain.

Tomorrow morning, we're getting on a pair of tiny ropes,

no bigger than my little finger, and we're going to

drop off into the abyss, alongside the highest waterfall on earth.

I can't think of a more fitting finale

to what has been an extraordinary adventure.

'The next morning, final preparations for our descent

'are well under way.'

We're about to start abseiling down it and my initial thoughts are,

"It's absolutely spectacular."

'The view is impressive.'

'But it's nothing compared to what we're about to experience.'

'It's time to launch myself down the cliff.'

OK, last few checks.

Everything good to go.

Pretty dizzying.

Whoa.

It's a very, very long way up.

OK, this is always the nervy bit...

..going from good solid rock into open air.

Whoa!

That is out of this world!

I feel like a very tiny spider on one single thin line of silk.

Honestly, it's one of the most extraordinary views I've ever seen.

I have the huge forest valley below me,

and the world's biggest waterfall off to the side of me.

This is awesome.

'I'm no stranger to grand views from a great height,

'but this is something truly special.'

Whoa!

-Nice.

-That is... "Nice"?!

That's the understatement of the millennium.

'And the rest of the team clearly feel the same way.'

Wow.

It's... I'm speechless!

'But this is only the beginning.

'There are over 30 more abseils

'between this ledge and the jungle below.'

That's it. The only way is down.

'It's obviously going to be punishing work

'getting off this Tepui.'

Give it a pull.

Thank you.

Three, two, one.

Keep low!

'Eventually we arrive at the base of the cliffs,

'and onto an outcrop with a magnificent view of Angel Falls.'

This is our last view point of the falls.

It's pretty special isn't it? It's mesmerising, it's hypnotic.

Yeah, it is. It would be like jungle abseiling

from here to the bottom.

'Although we still have several hours of descending

'through dense rainforest to go,

'this view of Angel Falls, from the rocky outcrop,

'feels to me like the moment that we leave

'the world of the Tepuis behind.'

This has been a really remarkable expedition.

Places like the Angel Falls makes you feel like an explorer.

It makes you feel that

there are still incredible things to be discovered.

There is a real purpose to exploration, especially now

because so much of our planet is being lost,

is being destroyed by us as human beings.

The parts that we can discover afresh with new eyes

and learn to treasure, you know, we're going to want to try

and preserve them, and that's incredibly important.

Otherwise, sights like this are going to be lost,

and my children will never get a chance to see them.

'This expedition to shed new light on the Tepuis of Venezuela,

'will hold so many memories for me.

'I travelled by land...

'water...

'and air.'

No way!

'And was almost killed by a plane.'

'I tried to conquer cliffs that had never been climbed.

'But was forced to retreat when pushed beyond my limits.'

No, no, no, no!

'I experienced the otherworldly beauty

'and intense claustrophobia,

'hidden deep within the mountain.'

I don't like this at all.

'And ventured where no-one had been before.'

'I encountered exotic...'

Oh, it hurts so much!

'..strange, and dangerous creatures.'

Whoa!

'Finally I abseiled alongside the world's highest waterfall.'

'And I will never forget the camaraderie of the people

'I shared this adventure with.

'So I'm leaving this fabulous land,

'not only with a sense of immense achievement,

'but also knowing that there is still

'an untold amount yet to discover.'

We may not have achieved everything that we set out to do here,

but I don't think that's a failure, far from it.

In fact, I think it's a really powerful idea

that there are still landscapes that are stronger than us,

places that we can't tame.

And I, for one, am definitely going to be back.