Abereiddi to Barmouth Coast

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.

Subtitles by Red Bee Media Ltd