Gower to Anglesey (45min) Coast

The coast of south-west Wales.

Our earliest ancestors came to the edge of our islands for sustenance

from land, sea and sky.

But this cathedral of the elements didn't only nourish their bodies,

they also found succour for the soul.

Far on the horizon lies the vanishing point

between the sea and sky.

Out there, it seems as if the heavens and the earth meet.

No wonder then that natural "walkways to eternity",

like this one, where the land snakes out into the sea,

are special places with spiritual power for pilgrims and pagans alike.

We're on a journey from one great finger of land, at Worm's Head,

to another on the Llyn Peninsula.

Travelling up the heavenly west coast of Wales to explore divine

and devilish goings-on along this stunning shore.

On the Isle of Skomer, Miranda explores a seabird paradise.

There's a taste of military shock and awe, 13th-century-style, for Mark.

Iron gate there, iron gate there...

The famous murder holes.

And Alice tries to solve the riddle of the singing sands.

Quiet, please, we are recording the squeaky beach.

This is Coast.

Having crossed from Brittany,

we're still in the land of the Celts, but back on home turf.

Our journey continues, heading for Anglesey,

starting at Worm's Head in Gower.

These long fingers of land on the western edge of Britain

reach out to caress the Irish Sea.

Gower was the UK's first designated Area of Outstanding Natural Beauty, and at the very tip

of the Gower Peninsula lies this remarkable headland - Worm's Head.

Viking's coined its name "ormr" from the Old Norse for serpent.

I can see why that green spine of land reminded the Vikings

of a serpent reaching out to sea.

Those same Norsemen buried their dead in tombs they built

over there on Rhossili Down.

Who would dare disturb the spirits of their departed

with such a fierce beast guarding the shore?

Even today, you've got to be brave to take on the Worm's Head.

The scramble across the jagged causeway

that connects it to the mainland isn't for the faint-hearted.

I've got to read the tides right - the currents that come swirling in

across the rocks can easily cut you off, or wash you away.

You can't afford to hang around.

One adventurer who got himself marooned out here

was the poet Dylan Thomas.

He told tales of being trapped on the rocks by the rising tide as darkness fell.

Now it gets really tough.

Just as I need to get a move on, the landscape and the elements are against me.

Once you've scrambled along the rocks of the low neck,

you reach a jagged arch, cut by the sea clean through the body of the beast.

It takes you to the outer head - the loneliest tip of Gower.

They call this the Devil's Bridge, and I'd love to cross over and carry on,

but I'm going to leave that little slice of heaven to the birds.

I'm here in May, and at this time of year,

the tip of Worm's Head is out of bounds

because the seabirds are busy nesting.

I'm glad to get a head start on the tide.

It's scary how fast the sea rushes in to make this an island once more.

But there'll be other great walkways into the sea to explore

as I venture westward along the Welsh shore.

Worm's Head is just a tiny little snake of land poking its head

out of the Gower Peninsula, which itself

pokes out like a pimple on the face of the South Wales coast.

But this is no unsightly blemish,

more a site of serene beauty scraped clean by the last ice age.

We continue our journey westward along Carmarthen Bay.

Crossing the water into Pembrokeshire, Tenby's sweeping golden beaches

are just a taste of the majestic shoreline that awaits us.

Some of the best surfers in the world are drawn to open, wind-blown bays, like Freshwater West.

Hi, I'm Kirsty Jones, I'm a professional kitesurfer.

I'm Kitesurf World Wave Champion and I've come to Freshwater West

to train for my next World Cup competition.

It's my favourite beach to come surfing.

It's a world-class surfing break and it's also really great for kitesurfing.

It's a really special place for me because that's where my roots are from

and it's always nice to come back, even though I travel all over the world.

OK, here we go.

I'm going to hit the wave on this one!

Kitesurfing is using a big power kite to pull you along on the water,

and you can do tricks, you can do jumps.

I'm going to do a little grab now.

Freshwater West is just amazing

when it's like this.

There's something really special about

the feeling of the sea air and the sea coming back to Wales.

I just love it.

Many Welsh islands owe their names to travellers.

Often Vikings can take the credit,

and Skomer is no exception.

Skomer derives from the Old Norse word "skolm", meaning short sword.

Vikings aren't the only adventurers that have been attracted to these islands.

This is a seabird paradise that welcomes some of the greatest airborne travellers on the planet.

Miranda's exploring this lush outcrop seeking out old friends and new arrivals.

I've visited Skomer quite a few times

and it's lovely to be back,

but every time I come here it's like I've got to get to know the island

all over again, it's ever-changing. It's a place of so many different facets.

One of the most precarious habitats is the Wick,

a sheer cliff with ledges ideally suited to nesting birds -

razorbills, guillemots, kittiwakes and fulmars.

I'm going to explore this fantastic abundance of birdlife, not just by day, but at night too.

In daylight, it's puffins that rule the roost.

And it's not rocky sea cliffs but rabbit burrows

that's their idea of a perfect des res.

This is one of the most important puffin colonies in north-western Europe.

The best way to appreciate the puffin's lifestyle is to get in the water with them.

Island warden Jo Milborrow is going to help me snorkel right up close.

I'm absolutely dying to get in. It's been a warm day and the water

looks so inviting and there are loads of puffins behind us.

-Yeah, they're great, aren't they?

-Yeah, hope we can get close!

-Hopefully, if we go in they'll come and have a look at us.

-Brilliant.

Oh, it's cool! It's very cool.

-That's chilly!

-It's very chilly.

Puffins are easily spooked, so we have to be patient and move slowly.

But we're soon rewarded with a rare chance

of swimming within just a few feet of them.

Some of Skomer's grey seals are lounging nearby, but for me,

it's the puffins that steal the show.

Absolutely surrounded by puffins, maybe just five or six feet away from me.

Some of them just skimming over the top of my head.

Incredible, they just seem to be oblivious to the fact

I was there, maybe I just fooled them that I was a seal.

Puffins certainly steal the limelight during the daytime.

But Skomer attracts vast numbers of globe trotters

who are much harder to spot until night falls.

Every summer, Skomer welcomes back a flock of old friends,

birds from the island who've travelled way out

to the coast of South America, a round trip of 18,000 miles,

and they come back here to the island, often to within just a few feet

of where they were born, to mate and breed.

I'm in search of one of the greatest adventurers of the animal kingdom -

the Manx shearwater.

This tiny island off Wales

becomes an extraordinary landing strip for Manx shearwaters,

returning after winter from fisheries far down in the South Atlantic.

Because they're shy, nocturnal birds, you'd be hard pushed to see them in daylight.

But, as the sun sets, the atmosphere really changes.

SQUAWKING

That cacophony means the Manx shearwaters are arriving

in their thousands, and I can just glimpse them in the darkness.

Professor Tim Guildford is going to help me get a closer look.

-They're everywhere.

-They are, the place is absolutely littered with them.

And this guy has probably just landed.

I'm guessing this is a non-breeder.

Fabulous!

So this one's probably just a recent prospector

-who's looking to mate.

-He's beautiful.

I don't know if you can see on the top of the beak there, there's two little holes.

These nostrils are actually salt-excreting glands.

-Yes, like a storm petrel.

-Yeah, absolutely.

That allows this whole family of birds to live in the open ocean

without ever having to drink, so they can essentially either create

their own water metabolically,

or they can excrete salt sufficiently not to need fresh water.

They look a bit hopeless on land, the legs are placed

so far back on the body that they can't balance well.

They flatten themselves out, don't they?

They're sort of waddling very low.

-It's a very strange gait, isn't it?

-A very strange gait, yeah.

'There are more than 100,000 breeding pairs on Skomer,

'and nest cameras provide new insights into how they rear their young.

'Researchers like Tim have also been tagging the birds with electronic geo-locators.'

-OK, that's great.

-OK.

Here they come.

-Brilliant, so this is one of the tagged birds?

-And on this leg...

That's the geolocator? It's so small.

Yeah, on this leg is the geolocating device...

The electronic log of this bird's position is downloaded to produce detailed maps.

This tells us, for every day and night of the year, where the bird has been.

So at last, now, we can reconstruct its entire migratory journey.

The male is the black one and the female is the purple one.

We see this outward migration down the west coast of Africa,

across to Brazil and then down to Argentina to over-winter.

They head back then in the early spring,

they take slightly different routes, but what you do see

is this extraordinary curve through the Caribbean.

They don't come back the way they went out.

-Isn't that incredible, they're not doing the same journey there and back?

-It is.

-I wonder why.

We think they're exploiting the North Atlantic currents,

this circular current.

So the currents and the weather systems move like this

so they're basically following weather systems,

making it efficient, using the winds.

And soon they're off, back out to sea.

By daybreak, the shearwaters have vanished,

perhaps the most remarkable secret of this magical seabird sanctuary on the Pembrokeshire coast.

Across St Bride's Bay is the tiny harbour of Solva.

We're nearing the western edge of Wales.

St Davids is Britain's smallest city with Wales's biggest cathedral.

The nation's patron saint established a monastery here in the sixth century,

when the sea was a religious highway spreading the word around early Christian Britain and Ireland.

Pembrokeshire has Britain's most coastal national park,

a glorious shoreline that you can walk from beginning to end

enjoying a coast path 186 miles long.

It helps to get your walking boots on to find the surprises tucked away along this shore.

Like here, at Abereiddi.

The locals call this place the Blue Lagoon,

and its aquamarine colour

gives it the look of a tropical pool, but it's far from natural.

Now it's a playground for divers and coasteers,

but this place is a clue

to an industrial boom that happened here more than 100 years ago.

It's not just the sea that's been eating away at this coast.

The locals have done their share of nibbling too.

This was a slate quarry that once employed around 100 workers.

And just along the coastal path, another giant hole in the ground.

An exceptionally hard stone - dolerite - was blasted out

of the cliffs here, an ideal material for buildings and roads.

The rock was hauled a short distance by rail

to the tiny harbour at Porthgain.

The village is still dominated by enormous brick hulks.

Here the stone was crushed and graded in five separate bunkers,

then it cascaded down a loading chute

into boats waiting at the quayside.

Today, you see just the odd boat going in and out of the harbour, fishing for crabs and lobsters.

But when the quarry was going full tilt, the company had six steam coasters

and at one time there were 100 other vessels, all registered at the port,

and they're not entirely forgotten either.

The nameplates of many of them are inside the pub, nailed to the walls and above the tables.

A remarkable industrial operation dominated the surrounding area

right up until the 1930s.

Unearthing this lost world of endeavour

is a bit of archaeology anyone can do, so much still remains.

The Teifi Estuary marks the dividing line between Pembrokeshire and Cardiganshire,

with its own popular holiday destinations - resorts like Newquay

and the Georgian seaside town of Aberaeron.

Further north is Aberystwyth, a University town used to gowns...

and beach towels.

That dual personality is captured in this grand Victorian building, the Old College.

It was conceived as an opulent resort hotel,

but it went bust before it was finished,

only to be snapped up for a bargain price in 1872

by the founders of Wales's very first university.

It was all made possible by 70,000 donations from the public,

people like miners and quarrymen who were passionate

that education was the path to a better life.

Now, Aberystwyth is known as the university founded on the pennies of the poor.

North from Aberystwyth to another Victorian seaside resort - Barmouth.

The Mawddach Estuary, where the Snowdonia National Park sweeps down to the sea.

The poet William Wordsworth called the mix of coast and mountain here "sublime".

But there'll be no time to stand and stare for Nick.

I'm about to find out what it takes to compete in one of the world's

toughest sporting challenges, a race on land...

and at sea.

Every year since 1977,

teams gather in Barmouth to launch an assault

on Britain's highest mountains.

I've come here to train with the crew of the Mistral

as they prepare for the gruelling Three Peaks Yacht Race.

-Hi, Helen.

-Hello!

-Very good to meet you, can I come on board?

-Welcome aboard!

-Thank you.

-There you go.

The course works its way up the west coast, stopping at Snowdon,

the highest peak in Wales, Scafell Pike, England's highest peak,

and they save the hardest till last.

Britain's tallest challenge, Ben Nevis.

To get between the climbs, contestants take to their boats,

all the way to Fort William.

Right, I'm ready.

Yeah, go for it.

Can we just ease that sheet a little bit, please?

What's the wind blowing at?

That last gust was about an eight,

so 40 knots of wind.

-How does it feel?

-The boat feels great, how does everybody else feel?

Yay!

Mind the sheet.

OK, guys, ready to go?

There's a crew of five -

the skipper, two specialist sailors and two runners.

Every second saved at sea is a stride up the mountain,

so they run a tight ship.

The race is timed for boat performance speed

and catching the right tide, and if you catch the right tide,

you can get 6-12 hours ahead

-of people who missed that tide.

-Will you sail at night?

Our first difficult navigation is coming through

the sand bar at Caernarfon at 2am, which will be dark.

That sounds a complete horror story.

Yeah, essentially. It can be tricksy and quite difficult.

In all, they'll have to sail nearly 400 miles to get between Britain's three tallest peaks.

When they arrive at a climb, they've got to get inland quick.

The first port of call is Caernarfon, the stopping-off point for Snowdon.

Whatever the weather, tourists will pay to take the train to the summit,

but the race contestants will have to run up it.

Our brief training run over, we get to do something they won't do during the race itself -

take a rest!

This is just a taster, I guess,

of what you're going to be facing when the race kicks off properly.

How many miles are you going to be running on the whole race?

In total, there's over 100km.

The leg we're on today, the Snowdon leg, is 36km.

You're running up here at night, aren't you?

Yeah, it will probably be about 4am

which is going to be rather unpleasant for both of us.

What happens when things get really difficult or go wrong?

Instead of a sleeping bag, we carry a blizzard bag which is...

-Which I can show you here.

-It weighs about 300g,

so a lot of the runners will be carrying these

which are double-foil blankets, so they insulate you a bit.

They're a bit like a sleeping bag.

So in a race like this, every gram counts,

every gram saved is another few seconds you can cut off the race.

Exactly, faster up the hill, yeah.

So let's roll this out,

find a nice little hole for you to sleep in and go in.

Just wriggle inside do we?

Do you take your shoes off first?

-I guess you would?

-No, not at all.

It's cosy, isn't it?

And if it was really cold, we'd be in there with you as well!

Go on then, Maria.

It took the team five days - and 38 minutes, to be exact -

to reach Fort William. Of the 32 yachts at the start line in Barmouth,

they came in a creditable 13th.

I only wish I could have stayed with them on their epic journey.

Struggle's no stranger to this coast.

People come to pit themselves against the landscape.

But the landscape has also been pitted against the people.

This coast doesn't only promise a paradise of freedom,

it's also been transformed for terror

here at Harlech.

At the end of the 13th century, an English King invaded Wales,

determined the locals would submit to his divine right to rule.

On this spiritual shore, Edward I of England hatched a devilish plan

to enshrine his authority over the Welsh - in stone!

What a piece of work and truly awe-inspiring.

It looks terrifying now,

but can you imagine what it would have looked like 800 years ago?

I want to bring this building back to its former glory

and discover what made this one of Britain's most formidable fortresses.

Although the stone walls are largely intact,

Harlech Castle has been stripped of its strongest defence -

the sea.

Back when it was built, I would have been walking on water,

not the sand dunes that are here now.

Rhian Parry knows what's happened to the coast

since the castle was constructed.

We do know from this map of 1610 by Speed

that it was quite a different picture.

You can see, here's the castle.

We're presumably somewhere by that mermaid.

And look at the ships going in and out of the estuary.

The tradition is, and there's some documentary evidence, of course,

that there was a port for Harlech at Ynys at Ty Gwyn y Gamlas,

which literally means the white house of the canal,

and it's likely that this was all marsh

and at high tide was under water completely.

-So, Ynys island is...

-Yes, is this one here.

So, if that was an island then, in the medieval period,

this was all marsh and open water.

Indeed, and there are lots of little islands, and the place names tell you they were islands

and people didn't call them islands for nothing.

Restoring the sea to lap against the walls of Harlech castle

is step one of my medieval make-over.

This is how it looked when Edward I of England built it to conquer the Welsh.

But the sea was more than a barrier. It was also a gateway.

Andrew, why have you brought me to this lump of masonry?

The name is explanatory in itself - this was the water gate,

and the implication is that the water was adjacent to it.

The sea actually lapped up onto the side of these rocks?

It did. So you've got to imagine water down here.

-With jetties and ships and everything?

-Certainly a bustling harbour,

because they had an enormous amount of material to get up.

All the stone and iron they were bringing in, food.

-They were feeding 900 men at one point.

-So how do you get up there?

There's a path that goes up and I'll show you where that is.

The site of the castle starts to make sense.

With water guarding one side and steep slopes on the other,

there was only one way in - a landward gate

which was heavily fortified.

Just look at them, those towers!

One, two, three, four towers!

Yeah. They give an enormous aspect, don't they?

Any attacker who got this far would have to breach the gatehouse,

a massive defensive obstacle that dominates the castle.

You're making a huge statement, that this is the strongest bit.

Yeah, very definitely.

And this is sort of the chamber where...

This is the chamber where you didn't want to be.

-Two arrow slits.

-Two arrow slits either side.

So, crossbows would have come through there.

You've got iron gate there, iron gate there...

-And attack from above as well.

-Murder holes.

-Murder holes pouring down onto you.

-Boiling oil...

Yeah, that sort of thing.

This concentric design, walls within walls,

held back the hostile Welsh nearby.

That's the Snowdonia range of mountains over there, and there's Snowdon.

And this was of course the Welsh stronghold

of the Princes of Gwynedd.

This was the real point that Edward had to get to, the bit he had to crack.

So what was his big idea?

He was going to encircle it with castles.

So Harlech is one, Caernarvon is the other on the north

and then you've got Conwy, and then slightly later,

Biwmares was built as well.

And this really represented, finally, the conquest of the Welsh.

It did, yes, yes, very definitely.

It's likely the grey stone walls of Harlech Castle

looked very different in its heyday.

Edward had the structure plastered with a white render of lime mortar

and we're looking for the evidence.

Let's see if we can find some.

I think you'll be lucky!

Presumably, you find it in, sort of, corners, where it's protected.

Hang on, what's up here?

-That looks like it, doesn't it?

-What's that?

-Oh, goodness.

-There it is,

just a little bit. That's presumably the protective face.

Yes, it's overlaying the stones there.

Yes, I would suggest that is some of it.

-There's the original Edwardian mortar, lime render.

-I think it will be.

Look, it's just like, look behind...

I know that's inside.

Yes, inside the window reveals that, that's astonishing, isn't it?

-There it all is. So you've got render, and then lime wash on the outside.

-Yes.

Wouldn't it be great to lime wash the castle bright white?

But I guess no-one's actually going to let me do that,

but I have found a wall just down the road where we can try the stuff out.

The castle's coating of lime render was probably finished off

with this stuff - bright white lime wash.

Lime wash is the most marvellous material,

one of the great forgotten things from the Middle Ages.

It absorbs carbon dioxide and hardens just like stone.

The trouble is, to keep it bright and white, you have to do it every year.

It's bad enough painting a little wall like this.

Can you imagine what it was like painting a whole castle?

So the question is, why bother?

Modern weapons are all about stealth, but in an earlier age,

this fortress was very much about broadcasting a message.

The building wasn't hiding, it was standing out,

a brutish display of English power.

This was the castle in full glory,

the shock and awe of the 13th century.

Can you imagine what that castle would have looked like painted all white?

A symbol of the conquest of Wales, but also a provocation.

Just across Tremadog Bay, from the battlements of Harlech Castle,

you can glimpse another, less menacing fortress.

I'm on the Llyn peninsula at Cricieth.

Mark Horton, over the water at Harlech, isn't the only one with a castle on this coast.

There are plenty to go around.

The original Cricieth Castle wasn't built by the English Edward I,

but by his opponents, the Welsh Princes,

Llywelyn the Great and Llywelyn the Last.

I think his name, Llywelyn the Last,

tells you all you need to know about how things worked out.

The Welsh, from their power base in the mountains of Gwynedd,

rose up in a war of national independence in 1282.

But they were fatally divided and Edward crushed them.

Llywelyn was separated from his army and killed by the English at Cilmeri.

Edward then took over this Welsh castle at Cricieth and remodelled it.

But 100 or so years after the defeat by Edward I,

the Welsh were back for more.

There was another great uprising in 1400,

led by the charismatic Owain Glyndwr.

Owain was a truly national leader,

with powerful allies like the King of France.

By 1403, much of Wales was under Owain's control.

He even captured the mighty Harlech and held it for five years.

At Cricieth he tore down much of the castle

that the English had extended,

a grand gesture that ultimately proved futile.

The English struck back.

Owain's Glyndwr's revolt stuttered on, but he became a hunted man,

a fugitive and a guerrilla,

and nothing certain is known about him after 1412.

He slipped away then into the shadow world of myth and legend,

a so-called Son of Prophecy,

who would return from his mountain hideout

to free Wales in her hour of need.

Owain's yet to return to claim Cricieth Castle.

For now, it stands a silent sentinel,

guarding the sainted lands beyond,

the holy places of the Llyn Peninsula.

At the western tip of Llyn is the fishing village of Aberdaron.

And on the beach, the Church of St Hywyn,

the last stop for pilgrims on their way to the island of Bardsey.

Three pilgrimages here were said to be equivalent to one visit to Rome,

and tradition has it that 20,000 saints are buried on Bardsey island.

The Welsh coast is a fertile shore for the making of myths.

Here, legend tells of a city lost to the sea -

Cantre'r Gwaelod, the Welsh Atlantis.

And then you come to Porth Oer.

Here, there's more than a grain of truth in a local claim to fame.

Alice is on a mission to solve the riddle of the Singing Sands.

SQUEAKING

If you believe its name, this beach isn't just heavenly to look at,

it's also rather wonderful to listen to.

It's called the Whistling Sands.

It's not the wind that's whistling, supposedly it's the sand itself that squeaks.

To get to bottom of it, I'm joined by our acoustics expert David Sharp

from the Open University,

who'll be listening for the special music of this place.

-Hi, David, how are you?

-Hello, I'm fine, thank you.

Now squeaking sand, I'm getting a tiny squeak as I'm walking along, but it's very quiet.

OK, well, just try scuffing your foot through quite hard and see what happens.

Why don't we walk along a little bit and see if we can get that...

-SQUEAKING

-Oh, there we go.

-Oh, that was a good one.

-This looks quite mad.

-That's it.

Brilliant, I'm getting it really nicely on the screen.

That's really squeaking!

I've never heard that before on a beach.

But we need more feet for the full effect.

Quiet please, we are recording the Squeaky Beach.

Yes, come on.

We'll make a line, I think.

What we probably need to try to do is to get in step.

-How did that sound, David?

-Oh, it sounded excellent. We've got a really good recording.

And is this beach unique in making this sound?

Well, it's not unique.

There are around 30 beaches in the UK that will have these properties,

but this is one of the better ones.

There's a good chance you're close to a whistling beach,

particularly on the west coast.

But why aren't there more?

What makes these beaches special?

I'm with coastal scientist Rod Jones

to find out what makes some sand sing.

What is it that makes the sound at a particular beach special?

Why isn't all sand the same?

Well, sound is affected by the energy of the environment where it sits.

So you've got your waves coming in and that's sorting the sand,

and it's taking some grains and pulling them offshore,

and others it's pushing to the top end of the beach.

And you've also got the process of wind, so when the tide's out,

these sands will dry, and the wind will blow across them

-and blow the finer particles up to the top of the shore.

-Right.

And the balance of the wave energy, wind energy,

and the supply and grain size of the sediments that you've got

at the back there, will define what the particle size

and characteristics are of the beach sediment.

How the wind and waves sort the sand depends on the shape of a bay.

We compared samples from two different beaches,

from here at Whistling Sands and from Cricieth nearby.

Right, shall we try this sand first? Which is from Cricieth.

If I just zoom in on it...

So, large grains and also a variety of different grain sizes as well.

-And shapes as well.

-Yeah.

You can actually see little particles of slate there,

as well as quartz and a lot of other things.

It's a very varied sort of sand.

OK, shall we have a look at the sand from Whistling Sands now?

Let's compare it with the last one and see how different it is.

That looks very different.

It is, isn't it?

The other one was much more varied in terms of grain size,

whereas this one seems to be much more dominantly composed of quartz.

-And it's much more uniform.

-Yes.

-In terms of size of grains.

They're quite well rounded, which means they will stack well together.

They've been sorted down,

a lot of the coarser and the finer fraction have been lost.

So wind and waves here have sifted the sand

into amazingly uniform, well-rounded particles.

But how does that produce a squeak?

David's come up with a super-size model of the sand grains.

David, what are you doing?

OK, well, what we've got here is

normal sand found on most beaches,

not regular at all. And what we've got here

is our singing sand, with lots of grains

of the same size and all very well rounded.

When you kick your foot through the sand, you cause it to shear.

-That means, you cause layers to rub across each other.

-Right.

Now let's have a look what happens with the normal sand,

and you can see that the grains just move up and down,

all at different times, at different rates.

With the singing sand, if you kick your foot through that,

what happens is that the grains all move up and down at the same time.

-They all move together.

-Yeah.

So why does that produce a squeak?

Well, it's actually the whole layer moving up and down

and the whole surface then acts a bit like a loudspeaker,

vibrating and causing pressure changes in the air above,

which we hear as sound.

SQUEAKING

And not just any sound.

David's had time to analyse the squeaks he recorded to see if

the beach is as musical as its nickname, Whistling Sands, suggests.

The interesting thing is the regularity at which we get these pressure changes,

so we get these increases in pressure happening at very regular intervals,

and that's all caused by the sand vibrating up and down,

just like we saw with the balls,

And that gives us this pitched sound, like a musical note, almost.

We can actually demonstrate that, if you want to just try

-singing some notes into the microphone, we'll record that.

-OK.

-OK, here we go. Right, off you go.

-# Ahhhh... #

SHE SINGS REGULAR NOTES

OK, that's brilliant.

If we zoom in on one of those...

And again, yes, you can see the regular pattern,

you've got this regular repetition

of these increases and decreases in air pressure.

And it's this regular change that gives us the sense of pitch.

Unlike most sand, this sand actually sings.

It really does sing, yeah.

Scientists are starting to explain the sound of the sands,

but there remains a magical quality to this place that's hard to define.

I love the fact the Singing Sands are still something of a mystery,

and it's a puzzle that's played out along the beaches of our coast,

in the sand under our feet.

The golden sands and clear waters of Llyn have a majestic backdrop -

the imposing mountains of Snowdonia.

And facing them across the water, Anglesey,

the island known as Mon Mam Cymru - the mother of Wales.

On its western edge is Llanddwyn Island, home of Saint Dwynwen,

the patron saint of Welsh lovers.

Which brings me to my final destination - Llangwyfan.

I'm on the causeway leading out to the Church in the Sea.

This is Llangwyfan, the church of Saint Cwyfan.

The Irish knew him as Saint Kevin,

and he was from Glendalough, not far from the stretch of Irish coast

directly across the water from here.

There's been a church on this site since at least as early as 1254.

It was extended in the 14th and 15th centuries

so it wasn't always the humble building that's here now,

because back in the day, there was a lot more land out here than there is now.

Over the centuries, the sea eroded this site

until the graves started to fall into the water.

So now the church sits here on a tiny promontory,

that, just like Worm's Head where my journey started,

becomes an island at high tide.

Places like this, sometimes part of the land, but sometimes part of the sea,

are reminders that everything is temporary.

No matter how hard we hold onto things,

our grasp of them is momentary.

And just like the tides around this promontory, we're just passing through.

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