-I'm traveling the world, exploring secrets and wonders...

This is really tight!

...an adventure by land and sea to the most fascinating places...

This is absolutely incredible.

...where I've been given special access to significant and surprising treasures...

It's so tiny and absolutely unique.

...buried in ancient sites, extraordinary buildings and glorious works of art... that help to explain the story of us.

Come with me to discover how the past shapes our lives.

This time, Gibraltar -- an iconic landmark in sight of two continents -- Europe and Africa.

This rock's unique geography and prime location has given it a front-row seat across thousands of years of history.

Gibraltar, or simply the Rock, a British overseas territory, might only span 2.5 square miles, but it is packed with treasures.

-Welcome to the Lost World.

-It surveys the Strait of Gibraltar, an artery linking two great seas -- the Atlantic and the Mediterranean.

It's just one small rock, but it's been a driver both for world history and for our imaginations, a rock that's apparently at the edge of things, but that is actually right at the heart of the human story.

From Neanderthal discoveries to Admiral Nelson and the Battle of Trafalgar, great Islamic citadels and the top-secret tunnels that inspired James Bond... Look at that.

...this rock has witnessed the whole sweep of the human experience, so I can promise you some rich and rather unexpected treasures.

♪♪ ♪♪ Gibraltar's stories and histories are dominated by a towering 1,300-foot Jurassic limestone rock that rises out of the sea.

My first treasure dates back before history, before prehistory, before the invention of time as we know it, and it's hidden not on the Rock but within it.

It's the lost world of the Neanderthals, who lived in some of the 200 caves which honeycomb the Rock.

Ever since a ground-breaking discovery was made here back in 1848, Gibraltar has offered a rare glimpse into the lives of our prehistoric forebears.

A fragmented female skull was discovered and pretty quickly, people realized there was just something a bit odd about her.

She's got this very pronounced brow bone and a really elongated cranium.

But the problem was, she was unique, she was unprecedented, there was just nothing to compare her to.

Then, just eight years later in the Neander Valley in Germany, a male skull with very similar features was discovered and that individual was named a Neanderthal.

So by rights, Neanderthal man should be called Gibraltar woman.

Almost 80 years after the discovery of that first skull, a pioneering young archeologist called Dorothy Garrod returned to the Rock to delve deeper into that initial extraordinary find.

In 1926, Dorothy had excavated an entire cave and just a few hundred yards from that original skull, she discovered this, a child who she called Abel, after the son of Adam and Eve, and suddenly a single find had become the community.

Thanks to Dorothy, tiny Gibraltar had become one of the world's most significant Neanderthal sites and the prolific discoveries made here since are challenging the view that simple Neanderthal cavemen and women were wiped out 40,000 years ago by us, Homo sapiens.

Instead, a new picture's emerging of a thriving, much more complex community of people, so it's a real treat to visit the archeologists whose ongoing discoveries are transforming our understanding of Neanderthal life.

So I'm just coming down to the cave complex, where there are genuinely incredible Neanderthal finds.

They're excavating right now, and you're not normally allowed in, but I've been invited.

Is that Clive?

Clive, hi!

-How are you?

-I'm good!

-There we go.

-Ah, brilliant!

What a treat!

Thank you.

-Come down.

Welcome to the Lost World.

-The Lost World!

I'm delighted to be here.

Thank you so much.

Professor Clive Finlayson is Gibraltar's leading paleontologist and has spent decades researching its Neanderthal past.

To get to his dig site, it's 300 steps down a remote eastern cliff face to sea level.

Clive, I know we're wearing the hard hats for the rocks, but they're quite useful for the seagulls today, as well.

-They're very useful.

-Not so friendly.

Is it nesting season?

-It's nesting season, yes.

-Okay.

-Now, are you ready for a first impression?

-I've been hardly able to sleep!

Oh, my goodness!

These magnificent caves are such a significant Neanderthal home, in 2016, they became a UNESCO World Heritage site.

Clive, I have to say, I didn't realize it was that size!

That is spectacular!

-No, they are massive.

-It's like a cathedral, isn't it?

-Come and see it over here.

[ Both laugh ] -I want to draw out the moment, it's too exciting!

♪♪ -How you doing?

-Yeah, good!

Just...[laughs] It is indeed quite a climb.

♪♪ First of all, I cannot believe this place.

It is just extraordinary.

So, how long has there been Neanderthals occupation in these caves?

-Maybe 90-odd thousand years, that we know, but my hunch is that it was probably a lot longer than 100,000.

-I mean, that is an incredible amount of time!

-We have to understand that Neanderthals probably lived on this planet longer than we have done so far.

-Mm.

Yes.

-And that puts it in perspective.

-So if we imagine 50,000 or 60,000 years ago, what is the typical Neanderthal day?

-Well, the idea that hunting is all they did is the stereotype that we've grown up with, but caves such as these are giving us a new vision of Neanderthal behavior.

We're beginning to realize how sophisticated it was.

They're hunting particular kinds of birds, particularly birds of prey like the golden eagle, for the feathers, for the talons to use as necklaces, so they would've been...

I can imagine a place like this and a very busy Neanderthal family doing all sorts of crafts and skills.

-The evidence Clive and his team are unearthing has huge implications.

Neanderthals weren't just surviving, but leading rich inner lives.

I know that you've had a really exciting, recent find here.

-Yeah.

It's an engraving.

It's an engraving made with stone tools, on the base of the Rock in one of these caves, and you can see it's a series of lines criss-crossing, so you can actually see the order in which they were made because one cuts across the other and so on, but we did a very detailed study of this to try and understand, "Was this a doodle?

Was this a casual thing?"

The first thing you realize is that, if you're trying to do this yourself with a stone tool, it's not an easy thing to keep a straight line like that.

So the first thing that we realized was, whoever's done this had done it before and was probably quite skilled at doing it.

It took us two hours to replicate this.

That's a long time.

This particular line took 60 strokes to do.

-What do you think it might relate to?

-Some people have said it's a map of the cave, it's a map of the constellations, it's a tribal sign.

Somebody else has said, "We all have it."

-We do!

-Is it art?

I don't know, but it certainly was done deliberately and has no functional purpose to it and it tells us a little bit about the minds of these people and how they were able to, like us, abstract in some way and symbolize.

-This 3D print of the engraving shows that far from being a doomed prototype of us modern humans, the Neanderthals were cultural, spiritual people.

There's this very sort of traditional idea about them, that they're rather stupid and aggressive, and then we come along as these kind of high-minded thinking literally Homo sapiens, but this shows how close we are, you know, how much we share.

-Absolutely.

Most of us who are of Eurasian origin would be expected to have Neanderthal DNA.

I carry Neanderthal genes.

With pride!

There is an argument that, you know, if we carry those genes, that they never really went extinct.

-Yeah.

-But there it is.

-It's beautiful.

Beautiful.

So enigmatic.

-Would you like to hold it?

-I would love to hold it.

Is that okay?

-There you go.

-Look at that!

That, a Neanderthal woman or man or child... -Child.

-...made those marks for a reason.

Clive, it's really... -It's special, isn't it?

It is really special.

Gibraltar's caves are the story of us.

They've transformed our understanding of the Neanderthals and also, by extension, of ourselves.

And the discoveries keep coming.

In 2019, it emerged Neanderthals have even left their mark in the sands here.

It's a story that's evolving.

Just recently, a faint footprint was discovered close to the sea, left by one of those Neanderthals.

It's really magical.

So they've left their imprint in the sand, the sun has baked it hard, it's been covered over, over tens of thousands of years, and then just after it's revealed, it starts to dissolve away.

So it's a ghostly reminder of the people who once called this place home.

The footprints were dated to just 29,000 years ago, over 10,000 years after we thought Neanderthals had become extinct.

So Gibraltar is their last-known sanctuary.

The secret world of the Neanderthals here is a thing of wonder.

It's been genuinely humbling to be allowed to get just a glimpse of their lives and also to be reminded that us, as modern humans, we don't have the monopoly on imagination and that we are as much a part of them as they are of us.

Some have framed Gibraltar as the edge of Europe, with the narrow Strait of Gibraltar a frontier before North Africa.

But in truth, the strait is less a gulf, more a highway between two continents.

That's Morocco, just 13 miles away over there, emerging from the mist.

And in 711, a man called Tariq ibn Ziyad crossed these waters to claim the Rock for his men and for his relatively new faith of Islam.

In fact, Gibraltar is almost certainly named after him, because originally this was called Jabal al Tariq, the Mountain of Tariq.

And that history-making moment gave us my next wonder, the Tower of Homage.

♪♪ Built in the early 1300s and almost 100 feet tall, this treasure is the single largest tower constructed when much of Spain and Portugal were Islamic.

The Tower of Homage sits at the top of a huge fortification complex that still dominates Gibraltar today, the so-called Moorish Castle.

It's named after the Moors, a label coined in medieval Europe.

But, frankly, that is a ridiculous catch-all title just invented by Europeans to describe people who were Arabs or Berbers or simply from North Africa and the Middle East.

In reality, a series of Islamic dynasties and cultures settled in Gibraltar over centuries.

From here, they conquered and spread their influence across the territory they called Al-Andalus, how the Spanish province of Andalusia gets its name.

A beachhead into Iberia, Gibraltar became known as the key to Spain and, to this day, its crest bears the tower and a small key.

And it was the so-called Moors who first really exploited the strategic importance of the Rock.

This was a prize they did not want to lose, and so they built these massive fortification walls all the way down to the sea that were described as a halo around a crescent moon.

♪♪ The Tower of Homage is scarred by the legacy of medieval sieges, as Christians tried to expel Muslims whom they viewed as foreign invaders.

This formidable kasbah, or keep, had just one entry point and walls up to 3 meters thick.

I'm not a fan of small spaces, but this is pretty unmissable.

This castle was besieged again and again and again and there's evidence of that all around.

Between the 14th and 15th centuries, the Tower of Homage was attacked nine times.

Most sieges were Christian attempts to unseat Gibraltar's Muslim rulers.

I don't know if you can see that rock in the middle there, that's basically a medieval missile.

It's a stone that's been catapulted at these walls with huge, huge force, so it's actually embedded inside.

I mean, these walls, sometimes they are meters thick, so you can just imagine the force and how petrifying it would've been to be trapped in here, because by the time you got the attackers this close, this is absolutely your last place of refuge.

♪♪ Despite constant attack, the intricate fortifications from the tower down to the sea pretty much held firm for centuries.

The town of Gibraltar is still shaped by the contours of these walls and ramparts.

And the formidable fortifications allowed civil society to flourish.

I tell you what's really interesting, is that one of the very earliest inscriptions describing this place says that it was dedicated to the god of peace, the god who pacifies.

And it's a reminder that even though this is a military construction, its story isn't all about conflict, because for 700 years, this was somewhere where women and men lived rich, fulfilled lives.

The so-called Moors lived in Gibraltar for over seven centuries, so, of course, they've left clues across the city.

So they were mending a drain down here, and they've discovered a bit of architecture from the so-called Moorish period, so that's a building at the time that was controlled by Muslim forces.

Wherever you dig here, there's something new!

And it's underground that the full splendor and sophistication of Gibraltar's Islamic past is most visible.

It is such a treat to be down here because I'm right underneath the modern streets of Gibraltar, but this is a Basque complex from the Islamic period.

These were originally open to the sky, so there'll have been kind of star-shaped sunbeams filtering through, and all this was just for one man.

He's used, probably from the Roman and Byzantine period, old classical columns to decorate his personal baths, but then on top, you've got that really distinctive horseshoe arch, which was very popular throughout the Islamic world.

And this is just the beginning.

Every time there's an archeological dig in Gibraltar, a little fragment of the Islamic period comes to light.

What you've got here is just a very simple terracotta water jar, but on it is written the word "Allah."

This golden age wouldn't last.

By the 14th century, the Christian kings of Northern Spain entrusted a noble family, the Guzmans, to oust Gibraltar's Islamic rulers.

For close on a century, successive generations of the Guzman Dynasty attacked the Rock.

Gibraltar's heritage bears witness to the struggle that was played out.

So this was originally a mosque or a private prayer room, so it was a kind of sacred heart of the castle.

But look at what's happened here.

So once the Christian forces eventually do manage to take Gibraltar, they came here and gouged this out as a burial for one of their great military leaders from the Guzman Dynasty.

It's a really conscious act of desecration and control.

♪♪ For 700 years, a variety of Islamic cultures have prospered and made Gibraltar the place it is today, down to its very name.

But the Guzmans and their Christian backers continued to have the Tower of Homage in their sights.

In August 1462, this castle finally fell and was eventually taken over by the Guzman Dynasty.

Now, you'd like to think this is all very neat and cut-and-dried and the story of the triumph of Christian invaders from the north, but actually, the Guzmans were originally from Morocco and may well have been born as Muslims.

It's a reminder that there are many blurred lines in history, and it is rarely a simple story.

♪♪ ♪♪ Gibraltar is somewhere that is still home to Muslim and Christian and Jewish communities and where people from Africa, Asia and Europe are happily neighbors.

That's what the great Mediterranean port cities all used to be like, they were multi-ethnic, multi-faith places, so Gibraltar now is somewhere you can feel as though you are in two times at once.

But one thing that is conspicuous by its presence here is Britishness.

You see its influence everywhere.

Since 1704, Gibraltar has been under British control and is officially a British Overseas Territory.

For centuries, it was an important naval base in the Mediterranean.

In fact, Gibraltar was the launch pad for the Royal Navy's greatest victory.

My next treasure is a unique bit of evidence of a moment that saw the birth of a national hero as a result of a battle that took place just a few miles off the coast of Gibraltar, the game-changing Battle of Trafalgar.

In the early 19th century, Napoleon Bonaparte controlled most of continental Europe.

If he defeated the British Royal Navy, his French Empire would also control the seas.

Under the command of Admiral Horatio Nelson, a British fleet set sail from Gibraltar to face a much larger enemy force at the nearby Cape of Trafalgar.

On October the 21, 1805, Nelson charged into the enemy ships.

Within five hours, they'd been decisively beaten, and for the next century and a half, the Royal Navy took control of the region.

This was the beginning of an unparalleled period of expansion for the British Empire.

But my next treasure isn't a cannon or a warship.

It's tucked away in Gibraltar's sumptuous Garrison Library, the so-called Trafalgar "scoop."

I do love this place.

♪♪ This was built just a year before the Battle of Trafalgar and it might seem rather sleepy, but it's the guardian of historical treasures.

The library holds every copy of the still-published "Gibraltar Chronicle," the second-oldest English-language newspaper in the world, only beaten by "The Times" of London.

And it's in this copy from 1805 that you can read the "Gibraltar Chronicle's" greatest-ever splash, the Trafalgar "scoop."

It describes a great victory that came with a terrible loss.

What we've got here is something remarkable.

So this is an edition from three days after the battle, and it gives us an eyewitness account.

It's really dynamic, you know, you get the sense that you're in the battle itself.

And we've got here a dispatch from Collingwood, the Vice Admiral of the fleet.

But actually, what Collingwood is describing isn't really the battle itself, it's the death of Nelson.

So we hear, "Our loss has been great in Men; but, what is irreparable, and the cause of Universal Lamentation, is the Death of the NOBLE COMMANDER IN CHIEF, who died in the Arms of Victory."

And then underneath, we discover his last words.

"Thank God I have outlived this day, and now I die content!"

So here, this is living proof that news really is the first draft of history and that this is how heroic legends are created.

♪♪ This is the very first printed account of one of British history's key moments -- victory at Trafalgar and the death of Nelson.

In fact, the "Chronicle" reported the news a full two weeks before "The Times" in London.

Gibraltar was shaping British history just as much as it was being shaped by British rule.

News of Nelson's death spread like wildfire.

In Naples, the poet Samuel Taylor Coleridge said that he had tears on his cheeks and that even the Italians had sorrow in their countenance.

This was becoming a story as fast as it became history.

Nelson's body was brought to Gibraltar before being sailed back to London for an enormous state funeral.

Across Britain, streets and pubs are named after Trafalgar.

Here was a foundational myth for a seafaring nation -- Nelson giving his life so Britannia could rule the waves.

In Gibraltar's Trafalgar Cemetery, resting place for some of the battle dead, these values of heroism are written in stone.

By dying as he did, Nelson became an archetypal hero, someone who gave their life for others and who perished fighting a military adventure in foreign lands.

It's been the same through history.

You think of the Greek heroes or even superheroes today in comic culture.

Isn't it fascinating that, as a species, we love the heroic?

We love the idea that, in bad times, there is always gonna be somebody who will be our savior?

Gibraltar, British yet exotic, was a resonant backdrop for this kind of national myth-making.

But just as the Rock helped usher in the British Empire's lionized golden age, it also witnessed its darkest hour.

♪♪ My next treasure lay hidden and buried for over 50 years.

It's no exaggeration to say that Gibraltar was pivotal to the outcome of World War II.

Control those straits and you control access to the Mediterranean and to the Atlantic.

But from 1940, the Rock was under attack, bombarded from the air and from the water.

This was a disaster waiting to happen.

Nazi High Command made detailed plans for the invasion of Gibraltar.

They knew it was key to winning the North African and Mediterranean fronts.

For the Allies, the Rock could not fall into enemy hands.

And the extraordinary lengths they were prepared to go to are still drilled into Gibraltar today.

The security of Gibraltar was so critical, the Rock itself was turned into a vast military fortress.

So the civilian population was evacuated, they were shipped out to Morocco or scattered throughout Europe and 17,000 Allied troops were brought here to create an underground world.

So here there were hospitals and ammunition stores and bakeries in 30 miles' worth of tunnels.

And everywhere you go, there are still fragments and remnants of those hidden lives.

There are as many miles of tunnel underneath the Rock as there are roads above.

Most of these World War II-era tunnels have been explored and documented, but my next treasure was considered an urban myth until just a few decades ago.

Hi.

Smudge?

-Yes.

-Hi!

Bettany.

How good to see you.

Is it okay to come through?

-Please, come through.

-It's the most incredible place!

-It is.

-It's just extraordinary!

Phil Smith, better known by his army nickname "Smudge," is one of Gibraltar's leading World War II experts.

You hear about secret tunnels, but this really was secret.

Wasn't it?

It was classified as secret.

And he was in Gibraltar when some potholers made an extraordinary discovery.

-We're just approaching now the spot where they rediscovered the secret chamber, which is just here.

The caving group had been looking for years for the secret chamber, and in 1997, they just happened to stop here and they felt wind coming through from the corrugated iron sheets that line the tunnel.

So they removed the corrugated iron and instead of the limestone rock of Gibraltar, they found a man-made concrete block there.

-What a discovery, because I know this isn't -- It's not even on military maps, this, is it?

-No!

No, no, it's ultra secret.

-Incredible.

But we can get in?

-Yes, we can.

-Fantastic.

The cavers had discovered a top-secret military installation hidden within Gibraltar's existing tunnels.

-So here's the entrance.

You can see it's quite low, so please be careful coming through.

-I will.

Okay.

Oh!

I just banged my head!

-Are you okay?

-Yeah, I'm fine, I just banged my head!

Ahh!

It was constructed in the event of a German invasion of the Rock, acting as a secret lookout post from which Allied personnel could radio enemy plane and ship movements back to London.

Who would have thought this was here?

Extraordinary place!

-This is the main chamber.

-It's been secret for so long, the space is an eerie time capsule going back to the height of the war.

I know locally this is known as the Stay Behind Cave, but who's being left behind here?

-It was a team of naval ratings.

There was a team of six altogether -- a commander, two surgeons and three communication specialists.

This would've been home for them initially for a year, but later on, they had enough supplies in here to last out seven years.

-So their mission is to stay here, nobody knows about them, and they're being left here so they can be behind enemy lines if they need to be.

-Basically.

They could spy on the Germans and report back each night by radio of any troop movements, ships, planes.

-It's a huge complex, isn't it?

So it carries on... -Yes, as we go through here, we've got the toilets, the radio room and then we've got the viewing apertures so they can see out to the east side and also to the west.

-Every eventuality had been planned for so these six men could spend months, even years, hidden in the Stay Behind Cave.

If the Germans invaded, they were instructed to brick themselves in.

And those bricks are still here.

As a soldier, can you imagine what it would've been like for those men being in here?

-I've got some idea.

When I was here with the military, I did a 3-day exercise inside the Rock.

When I walked out into the sunlight after three days, I was totally dizzy and could hardly stand up.

These guys potentially here for seven years, that would take a particular breed of individual.

-Well, incredible.

It's moving being here, thinking of what they were prepared to do for the common good, for others.

-Yeah.

I have the utmost respect for those people.

-Is it okay if I go and have a look?

-Yes, please do.

-Thanks.

For those prepared to stay behind, this would almost certainly have been a suicide mission.

So this man-made cave is a chilling monument to Gibraltar's strategic importance.

These vantage points would be manned day and night.

From one side, you can see across to Morocco and here you've got the sweep of the whole Mediterranean, so they were watching out for enemy attack, but particularly planes landing at night.

Every night, they'd send reports back to London.

For over half a century, its existence was officially denied.

But newly unearthed documents tell another story.

There's a report that's recently been released from the Admiralty files that is top secret, as it says on the top, so it must've been classified, and this gives a really detailed description of how this whole area was going to be constructed and furnished.

We hear that it was going to be built 1,350 feet above sea level and that there'd be a tank for 10,000 gallons of water.

And that is here.

That's the tank there.

When it was first discovered here, the tap was switched on and it was still working.

Thankfully, Gibraltar wasn't invaded.

And although this treasure was never put to use, it's influenced our culture in a rather surprising way.

Constructing the Stay Behind Cave and, most importantly, finding those volunteers to man it, was a massive intelligence operation.

Between 1941 to 1942, this underground command center was the workplace of one spook who wouldn't stay in the shadows for long.

Now, there's one thing I can't not tell you about the Stay Behind Cave story.

The young naval intelligence officer responsible for recruiting those men was called Ian Fleming.

That's the same Ian Fleming who created James Bond.

Inside tunnels that span the full width of the Rock, I'm suddenly immersed in Ian Fleming's wartime Gibraltar and it feels very 007.

Ian Fleming definitely was familiar with this place, and there is absolutely no doubt that his military experience here on Gibraltar fired his imagination.

The character of M is almost certainly based on his superior officer, Admiral Godfrey.

When he was serving here on Gibraltar, there was a naval officer whose surname was Moneypenny.

And just think of those spy novels.

There's always a cave hideout or a classified operation and it seems that almost every Bond villain has a sinister mountain lair.

♪♪ The Stay Behind Cave is a treasure that, once again, reminds us of the hold Gibraltar has over our imaginations, where a top-secret tunnel complex, hidden for half a century, still shapes our popular culture.

But even the caves that inspired James Bond can't elude my final treasure... Uh-oh!

Hello.

...the wonderful and mischievous wildlife of Gibraltar and spellbinding geology of the Rock itself.

This landscape is so dramatic, the Ancients thought it must've been made by the uber hero Hercules, who used his superhuman strength to pull apart the continents of Africa and Europe, creating the Mediterranean and the Atlantic.

The land that was left by the side was known as the Pillars of Hercules, as it still is today.

Ancient authors imagined Gibraltar as the edge of the known world, the last stop before the legendary continents of Atlantis, and the geology and climate of the Rock certainly give it a mythical quality.

Easterly winds, known as the levante, smother Gibraltar in clouds but also glide in migratory birds.

The Rock isn't just a landmark for us but many animals.

Oh!

[ Both laughing ] I just saw my first one!

Fantastic!

Look!

Hey!

-There he goes.

-Hello.

Tour guide Angie Watkins is leading me to the wondrous creatures of these seas, first described by Romans.

Oh, he's coming towards us.

-Swimming, yeah.

Slowly, slowly, a little bit of patience.

-Oh, yes.

-So these are the striped dolphins we've got here.

-Okay.

Three dolphin species inhabit the waters between Gibraltar and the Atlantic.

-In the high season, we're expecting to see 3,000 to 5,000 dolphins.

In the area of the bay and the Strait of Gibraltar, this area, we have very deep, very clean water, so there's a lot of fish for these guys to feed on.

They'll also come here to give birth to the calves.

-Yes.

-They'll keep the calves here while they're very young, using this area as a training ground.

-Oi!

[ Laughs ] Yes!

That is ridiculously cool!

That is just showing off, frankly.

It's always magical when you see them because, I don't know, just the fact that you're sharing the water with these beautiful creatures.

And I love the fact that the Ancients always said that they were bringing messages from the gods.

It was the god of the sea, Poseidon, kind of giving you his blessing.

So it's a very calming feeling knowing that you're up close to one.

It seems that Poseidon might be on my side because one of his colorful messengers heads straight for our boat.

Oh, loads of them, there!

-He crash-landed on the boat, I think!

-So this flying fish just came in.

I think one's landed on... Oh, poor thing.

There, look.

We're gonna put him back.

Put him back.

Oh, he's gone.

Bless him.

He swam on.

Wow!

So they just came hurtling across the boat.

That is incredible to see.

So they were flying fish, and, again, the Ancients talk about them as being these kind of magical creatures in this part of the world, and one landed on the boat.

That's extraordinary.

Extraordinary.

What a beautiful, beautiful, beautiful thing it was.

You do really get a sense from that extraordinary rock jutting out of the landscape why this place has created this kind of microclimate and a microecology to go with it.

If the waters around Gibraltar preoccupied the Ancients, the vast network of caves within the rock became natural wonders in more recent history.

For hundreds of thrill-seeking naval officers and sailors in the 19th century, these caverns promised boys' own glory.

This is where you came when you wanted to be just a bit more adventurous.

I've been allowed special access into Leonora's Cave, deep inside the porous limestone, to see how the British presence has literally left its mark on the Rock.

If you made it this far down, there was even a sign post.

♪♪ This is really tight!

Oh, this is so awesome in here!

Far from the prying eyes of their superiors, Royal Navy sailors found Leonora's Cave ideal for settling personal disputes.

It came to have a reputation for being the best place to come to have an illegal duel.

But almost certainly, most of the visitors down here were just bored naval officers and military personnel or kind of adventure junkies, and, actually, if you start to look at the walls, you can see they've physically left their mark here.

So, um, the guys here have obviously come as a bit of a sort of lads' trip, so you've got Captain B. Walker up at the top, RES Ray, and they're all from the Royal Engineers and they came here in 1897 and they've scored the walls to heroically prove that they made it down here together.

As the 19th century wore on, Gibraltar's appeal grew beyond the British military garrison.

Early tourists also flocked to the extraordinary Saint Michael's Cave, treating it like a subterranean pleasure garden.

Word quickly got out that there were all kinds of exotic experiences to be had here and Gibraltar became a destination for a trip of a lifetime.

You can see here there are parties held here in Saint Michael's Caves, with these fantastic Victorian women in their crinolines and guys in top hats.

The guests describe these stalactites as looking like the trunks of palm trees and the lighting here in the cave like a halo of glittering gems.

But Gibraltar's most exotic and recognizable natural wonder hadn't been carved into the Rock over millions of years.

It's made its home on the very top of the monolith, a cheeky colony of monkeys.

The Barbary macaque.

♪♪ Now, there are a lot of theories as to how the macaques got here.

Some people think they've been in this region for five million years, some people think they came over with the Moorish occupation, others think that the Brits brought them here for hunting practice.

But however they arrived, the macaques have become a mascot of Gibraltar.

I'm meeting Gibraltar's resident vet, Mark Pizarro, whose team monitors Europe's only wild monkey population.

There are lots of theories about how the macaques ended up here.

What do you think?

-Personally, I believe it's been mainly a British thing.

I'm sure the Moors had them when they first came, but I doubt very much whether it's the same monkeys from that generation which are here now.

I believe the British would've probably introduced them and then they've just become wild here.

-What is it about the environment here that suits them so well?

-It's a perfect environment.

There's a lot of natural foraging, we have a lot of trees which they can feed off.

There's cliff faces where they sleep at night, so they're very protected, and there isn't any major natural predator.

So therefore, the monkeys here will survive till they're 30-odd years of age.

-Legend states that as long as the macaques continue to thrive, the Rock will remain in British hands.

This myth is taken dead seriously.

During the Second World War, with the monkey population dwindling, Churchill himself got involved.

It's incredible that it mattered so much to Churchill that he sent a troop ship over to Morocco to bring them back.

But I guess it was really important for morale at that time.

-Oh, yeah.

I mean, it's synonymous with Gibraltar, isn't it?

Therefore, you come to Gibraltar, you're gonna see the macaques.

-And I do love this idea that as long as the macaques are here, there'll be a British connection.

-Hopefully that'll be the case for many millennia to come.

-Enchanting, tenacious, these remarkable animals are a fitting mascot for Gibraltar -- the ideal companions for a place with such a distinctive story.

That's why the ecology of the Rock is a treasure.

♪♪ Gibraltar might only be 2 miles across, but it's mapped the story of humanity, from Neanderthals homemaking, through to the conflicts of the 20th century.

It is packed with hard history and culture, but it's also a reminder of the power of the human imagination to shape both our pasts and our future.

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