-Escape with us on a legendary journey along Scotland's purest and wildest river... -Where better to come on a day like this?

It's a fantastic part of the world.

-...as we pass through ancient, untamed Highland landscapes.

-What else would we be rather doing?

-We'll discover a world steeped in history and untouched natural wonders... -What we're looking at now -- this is unique in the British Isles.

-...a land filled with tradition and story.

-Does it get any better?

[ Chuckles ] You know, it's beautiful.

It's stunning.

-We'll meet and travel with the people who live and work alongside this unspoilt river... -It's just amazing.

-...on a 172-kilometer journey from the river's pristine mountain source... -I have a passion, I would say, for this river.

-Well, should we set off here?

-...to where its waters flow into the North Sea.

-It's a special place for me.

It's just a great river.

-This is one of the most scenic river journeys in the world -- Scotland's River Spey.

♪♪ ♪♪ Famed for its fishing and whisky, the River Spey is Scotland's third longest river.

♪♪ It majestically carves its way across the great Scottish Highlands 177 kilometers north of Edinburgh.

With no cities on its banks or motorboats on its waters, the river is renowned for its speed, purity, and unspoilt natural beauty.

♪♪ And this is where our journey starts, 16 kilometers downstream from the river's source at Loch Spey, 350 meters above sea level, high in the Cairngorm Mountains.

Here, its waters dyed by the peat carpeting this ancient landscape, the Spey is just beginning its long descent to the sea.

And we've arrived just as river biologist Brian Shaw and his assistant, Steve, are starting their working day.

-It's a great job, isn't it?

-On a day like this, what an office we have.

It's a fantastic part of the world.

-This morning, they've come to the 300-year-old Garva Bridge to begin their annual count of the Spey's famous wild salmon population.

-The salmon are an important species in this area.

They're called the king of fish for good reason, you know?

They're such a lure to, a magnet to, anglers from all over the world.

-For centuries, the Spey has been revered for its salmon fishing.

Now its fast-flowing waters are one of the last strongholds in Britain for this iconic fish.

-Lots of rivers in the U.K. barely support salmon anymore, but we still have a healthy river here now.

These species need good-quality water, and we're lucky still to have that here.

Go on, fishy.

-Salmon numbers have plummeted 70% across the country in the past 25 years, but the pure waters of the Spey are helping them survive here.

It's Brian and Steve's job today to find out if the young salmon are still reaching the highest levels of the river.

-Let's see what we can catch here.

It's the juvenile fish that we're looking for today that, ultimately, the adult fish that the anglers catch in, you know, two or three years' time, -And they've got an electrifying way of catching them using this nifty gadget.

-Basically, we're creating a small electrical field in the river here.

Any fish that are in the immediate vicinity are temporarily stunned, and, hopefully, we'll pick them up in this net here.

Happy with that?

-To assess the salmon numbers accurately, each fishing session is carefully timed.

-We're just trying to know the population structure here.

There's a lot of information we can gather from this stage.

-And they set to work recording the age and size of each fish.

-Okay.

So, that's a salmon.

I think it's probably a 3-year-old fish.

-This tiny salmon will soon leave the river and head far out into the Atlantic, but it will return years later to this exact spot on the Spey to breed.

-Their homing ability is a great thing -- leaping up waterfalls, surviving predation, even when they're juveniles.

It's quite incredible what they've got to go through to come back here, but they do.

They've been coming back here since the last ice age, I suppose.

-Today it's good news.

-I've caught a reasonable number of fish here, so quite happy with that.

-The number of fish shows the salmon population is still viable here.

-I'm just going to put them back in the river exactly where they came from.

-So the young salmon, like us, can make their epic journey to the sea.

-They're one of the most amazing fish, aren't they?

You know, on the Spey, the salmon are present, I think, 107 miles up from the sea, and that's the furthest traveled salmon in any river in Scotland.

Now, these are the real survivors that make it up here.

-And we're following the same path the salmon have taken for millennia.

♪♪ From its source at Loch Spey, the river takes us past the village of Newtonmore... to Loch Insh... and into the Rothiemurchus Forest.

Then the Spey carries us to the great fishing estate at Ballindaloch Castle... over the Knockando Rapids and through the heart of whisky country, under the Craigellachie Bridge to Spey Bay, where the river meets the North Sea.

♪♪ As we head east, following a path cleared by a glacier 14,000 years ago, the Spey becomes more powerful.

Sliding over the steep bedrock, it soon becomes the fastest-flowing river in Scotland.

As the wild peatland gives way to dense woodlands, the Spey becomes just about deep enough for us to continue our journey by boat.

Canoes are the only craft that can cope with the speed and depth of river here.

-[ Laughs ] -But first we've got to slide them off this hill.

-This is not the most elegant entry to the river.

-This high up in the mountains, there's no easy way to reach the Spey.

-I'm being a bit lazy.

♪♪ -Luckily for us, no one knows this river better than our canoe guide, Dave Craig.

-I love the Spey.

I love -- I love the Spey in total.

I have a passion, I would say, for this river.

♪♪ -Whether it's for work or pleasure, he's been paddling this river every week for more than 55 years.

-For me, the Spey is Britain's most beautiful river.

-Today, he's canoeing with his friend Jerry.

-Hey, Jerry.

Should we set off now?

♪♪ -It's just a short paddle across the flat, calm waters of Lochan Uvie, before the current can carry us on our way.

-You just get a fantastic aspect of the river, really, because you've got a fairly low aspect, so you're actually -- you almost feel like you're part of the river.

And I just think you get a greater ambience, I think, than what it would be of the river than you can even walking along the banks.

It's very untouched up here.

-As the powerful current carries us further east, the untouched woodland gives way to pasture, and the river begins to change.

-The river has a completely different character.

If I do, say, a five-day trip, then every day of the five days is different.

The whole topography of the river changes, both in terms of the riverbed and the riverbanks, as well.

♪♪ -After a few hours paddling, the Spey is sweeping us under the bridge towards the village of Newtonmore and to a new landscape rich in history.

-It's a multifaceted river.

A lot of battles were fought along the side of the Spey, and every part of the Spey, there are legends and true stories.

♪♪ -The Spey is carrying us into the ancestral lands of the mighty Clan Macpherson.

-The Macphersons have been here for 600 years.

This is Macpherson country.

♪♪ -Wild, pure, and fast, the mighty Spey is sweeping us through the dramatic landscapes of the Highlands and into the historic village of Newtonmore.

♪♪ With its stunning mountain views, the village was built 200 years ago by Victorians eager to enjoy life on the river.

♪♪ But long before Newtonmore existed, this part of the River Spey and all the lands around it belonged to the mighty Clan Macpherson, and they are still here today.

This is Angus Macpherson.

-The Macphersons have been here for 600 years.

They've been the dominant clan here.

This is Macpherson country.

♪♪ -The Macphersons are so proud of their family history that just a stone's throw from the river, they've converted a house into a museum dedicated to it.

-Well, special treat.

We're going in through the front door because the house is being rebuilt.

Got a few items on display or not quite as normally displayed 'cause we got the workmen in, but here they are.

And we got everything from these swords to... rather a fine epergne that was donated to a clan chief in 1885 -- in fact, that clan chief through the the glass there, who was a friend of Queen Victoria.

♪♪ -Amassed over centuries, much of the Macpherson memorabilia came from the clan chief's castle when they sold it in the 1940s.

-The cats are fairly moldy or motley ones, anyway.

They are the symbol of the Clan Macpherson, and we're very proud of it.

♪♪ -But what Macphersons are really proud of is their fighting prowess.

A Macpherson has served in the British Army since it was formed.

-Weapons and museums sort of go together a bit, and they're easy souvenirs to come bring back from wars.

-And when it comes to fighting, the most celebrated Macpherson of all was Angus's father, Sir Tommy Macpherson.

-That's my father's uniform.

He was a Cameron Highlander.

Then he moved on and joined the Scottish Commando.

-Nicknamed "The Kilted Killer," Sir Tommy fought behind enemy lines throughout World War II and became one of the most decorated soldiers in Scottish history.

-I was once asked what was it like to be the son of The Kilted Killer?

And I was completely flummoxed because I'd never thought of my father as a killer at all.

He was my father, and that -- that was his role in my life.

Um, and the extraordinary thing is that he'd done it all before the age of 25.

♪♪ -Leaving Macpherson country behind, the mighty Spey now takes us through the dramatic Cairngorm landscape and on towards the North Sea.

♪♪ The river is carrying us east to the clear, open waters and beauty of Loch Insh.

Then it's through the mountains and into the ancient world of the great Rothiemurchus Forest.

♪♪ But first we've got to cross this -- the Loch Insh Marshes.

♪♪ These vast wetlands, visited by thousands of migrating birds each year, are one of the most important nesting sites in Europe.

♪♪ But now the birds of summer have gone, and with the winter flocks yet to arrive, a calm has descended on the river.

♪♪ -The area generally is called Badenoch, and Badenoch means "the flooded lands" or "the drained lands."

♪♪ -Its powerful current dissipated by 10 square kilometers of wetlands, the Spey hardly appears to be moving here.

♪♪ -It's very flat water, so you're not here to get the whitewater buzz.

You're here just because it's very tranquil and... you got these trees overhanging the river, and it's almost like there are cushions of alders kissing the surface of the river.

Very serene, this part of the river.

♪♪ It has a lot of history and culture to it, and this is the main artery that carries the lifeblood of the whisky industry.

I mean, there are 50 working distilleries on the Spey.

♪♪ It's just such a wonderful resource.

-As the light begins to fade, the Spey brings us into this -- the beautiful Loch Insh.

5 kilometers long, 3 kilometers wide, and 15 meters deep, it's the biggest loch on the river.

And we've timed our arrival perfectly.

-We're coming to the end of our day, and I just think we could... go ashore here and, um, share a little dram, a little bit of Speyside's famous whisky.

Arriving on a moonlit night like tonight, it's just fantastic.

Where else would you rather be on a windswept autumn evening than coming off the River Spey?

Slàinte Mhath!

-But we can't go too hard on the whisky tonight because tomorrow the river takes us east... through the ancient mountains and into the heart of one of the most spectacular forests in Europe.

-What we're looking at now -- this is unique in the British Isles.

♪♪ -At first light, the River Spey almost looks like it's from another world as it flows through the heart of Loch Insh.

The air temperature is a chilly 3 degrees Celsius, but the Spey is a little warmer, and this creates a magical mist now rolling off its waters.

This is the only place on the river where sailing and motorboats are allowed.

But long before the sailors surface, the wild swimmers arrive.

♪♪ -Let's do this.

-[ Chuckles ] It is hard getting into that cold water in the morning.

Having to put yourself through that really, really sets you up for the day.

Whoo!

[ Laughs ] What else would we be rather doing than just being out here in this absolutely stunning loch?

-It's glorious, isn't it?

[ Both chuckle ] -Plunging into a cold loch can be risky, but Alice Goodridge is a hardy soul.

Before she set up the wild swimming group here four years ago, she swam the English Channel.

-Swimming in the Spey is just amazing, and we do it all year, even when it's icy.

I've got a sledgehammer in my car.

[ Both chuckle ] And I just break the ice and go in.

-Keen to show she's also made of stern stuff, Fiona is the group's newest recruit.

-One thing I've noticed is that my skin is beautifully soft now.

♪♪ -After 20 minutes in the freezing water, there's a big incentive to get out.

-I want my bacon butty.

[ Both laugh ] -Oh, that was amazing.

-Wonderful.

-[ Chuckles ] [ Ducks quacking ] ♪♪ -As the mercury rises and the mist clears, the loch is transformed once again.

-[ Squeals ] -The boats are rigged, and the fair-weather sailors set out to enjoy the autumn sunshine.

♪♪ But we are heading to where the bigger boats can't go.

As it leaves the loch, the Spey becomes shallower and faster once again.

Winding its way through the landscape in sight of the rounded peaks of the Cairngorms, the river sweeps us into the great Rothiemurchus Forest.

♪♪ Stretching far up into the mountains and filled with 10 million trees, it's a haven for wildlife and a magnet for tourists eager to see the wonder of sites like this... ♪♪ ...the spectacular Loch an Eilein, the Loch of the Island, complete with the ruins of a 14th-century retreat built by the local bishop to keep his tax collectors safe from marauding clans.

♪♪ In the 16th century, the entire forest was purchased by the Grant family, and they still own most of it today.

Johnnie Grant is the current custodian.

-My family came to Rothiemurchus about, uh, 400 years ago.

It's sort of just been handed down from father to son ever since.

This is the ancient natural forest which really always surrounds the whole Cairngorms.

These trees have been here since the ice age.

-Dominated by enormous Scots pines, Rothiemurchus was once part of the prehistoric Caledonian Forest that covered most of Scotland 8,000 years ago.

-What we're looking at now -- this is, to my knowledge, unique in the British Isles.

People talk about the remnants of the ancient forest.

This is the most special, and, certainly, it is one of the largest.

-Alph McGregor has worked on the estate for 30 years.

-I kind of like this time of year because you're beginning to get the... change into autumn colors, and the autumn colors -- there are very, very rich diversity.

But they're all the spectrum of color, from green right to deep yellow.

It's absolutely beautiful to see it through the season.

You've got the mature Scots pine here, and you've got birch 'round about, and nearby you've got juniper.

These three species are the prime mixture of this ancient Caledonian forest.

-The forest might be ancient, but it's not untouched.

For centuries, the estates harvested the Scots pines here for export.

-Timber has been taken regularly for the last 500 years, and that has been done on a sustainable basis, making sure that the trees do regenerate.

If we go back 100 years or more, these logs were transported out of here by being floated on the rivers to Garmouth, where there was shipbuilding.

♪♪ -Once the timber was cut and dragged to rivers in the forest, getting them onto the Spey took some ingenuity.

The timber was taken to the river, where it was then floated down.

But you would be surprised that you've got these massive logs here and how they would float in a little river like this.

-The remarkable solution was to create their own flood, and to show how that worked, Johnnie and Alph are whisking us high into the mountains.

♪♪ -We're up at Loch Einich.

It's a bit windy today, but... this was actually where they built a dam.

They created a flood farther downstream.

The dam actually started here.

It just went across the neck of the river there.

It was just sufficient to raise the level of the loch by two or three feet.

-Once the loch was full, the dam would be released, sending a wall of water hurtling downstream.

-It must have been a torrent.

Yeah.

So, you wouldn't want to have been standing in the river when that came.

♪♪ -The deluge would then carry hundreds of tons of logs out from the forest and onto the Spey.

The flood would soon subside, and the logs had to be pushed out onto the water with long sticks.

♪♪ The next issue for the loggers was that the huge 20-meter-long tree trunks would soon become stuck on the twisting river, and the Spey is now taking us through the forest toward their very ancient solution to the problem.

I've been fortunate enough not to tip over, but the day will come, I'm sure.

♪♪ -The River Spey is carrying us through the great Rothiemurchus Forest, following the same path the timber took 100 years ago.

Back then, to stop the massive tree trunks from becoming stuck on the bends in this river, the loggers would take their lives in their hands and go onto the water in these very ancient vessels.

♪♪ -Such a lovely, calm day to be on the water.

-It's a beautiful day to be on the water.

♪♪ -Basket-case craft like these have been unearthed in Bronze Age burial sites across Scotland.

Jane Wilkinson, with her friend Hamish, decided to bring these 4,000-year-old boats back to life by making their own.

-These are coracles -- woven boats.

This one is a coracle that's made from willow and hide, so it's from a big cowhide.

This is very much the traditional way of making them.

-Used for thousands of years on the Spey for fishing and transport, these precarious waterproof baskets didn't offer much protection to the loggers.

-If any logs got jammed under the overhanging trees, the coracle paddler would be poking them free with their paddle -- a really dangerous pastime, actually.

[ Laughs ] -Jane, a basketmaker by trade, made this, her first coracle, as an experiment.

I'd been making baskets for a long time, and I thought, "Well, I could make my own boat."

You make it upside down, staked into the ground, so it'd be positioned like this on the ground, and you'd weave from the mouth of the basket to the bottom of the basket.

And corals are made in exactly the same way.

It's a basket boat.

It's a woven boat.

-We made the first one, and the first thing we did is we threw it in the water and jump in it, and it was a kind of make-or-break, and it worked, so we kind of just got lucky with it and fell in love with them, I think.

♪♪ -You've really got to step into the middle of the boat.

Otherwise, you can just cap it and go straight out the other side, so we should try and avoid doing.

♪♪ They are incredibly maneuverable.

You can turn them on a sixpence.

So, here we go, just doing that figure-of-eight stroke.

I can draw it sideways very easily.

I can avoid Hamish, hopefully, and not do Dodg'ems with Hamish.

-I've been fortunate enough not to tip over, but the day will come, I'm sure.

-What I love about this is the practical physical connection to the past.

You look at the landscape in quite a different way.

Does it get any better?

[ Chuckles ] You know, it's beautiful.

It's stunning.

Yeah, I love it.

-And at the end of a sunny morning on the Spey, there's another great advantage to basket boats.

-You can carry these boats... which is about the only boat, I think, that you can probably put on your back.

♪♪ Whoops.

Nope.

-[ Chuckles ] ♪♪ -As the Cairngorm Mountains become more distant, the Spey flows into a new landscape full of lush valleys and rolling green hills.

♪♪ The river is carrying us towards the fabled fishing spots at Ballindaloch Castle and then through the Knockando Rapids and into the heart of whisky country, where we will stop for a dram at a Highland pub.

♪♪ Majestically winding its way through the autumn trees, the Spey brings us into the heart of one of the most beautiful fishing estates on the river.

This stunning 60-room wonder is Ballindaloch Castle.

♪♪ Started in 1546 and now complete with fairytale turrets and manicured lawns, it's known as the Pearl of the North.

[ Cow moos in distance ] It's also the ancestral home of the Macpherson-Grants... ♪♪ ...and these very famous cows.

Almost all the pedigree Aberdeen Angus cattle in the world are descended from this herd.

-They are beautiful, aren't they?

Absolutely beautiful.

-Guy is the latest in a long line of Macpherson-Grants to inherit the herd.

-The story begins in 1860, when my great-great-grandfather, Sir George McPherson-Grant, purchased a-a cow and started his own herd.

He went on to show selections from his herd all over the world and is renowned as the man who took the Aberdeen Angus breed global.

-As a breeding herd, none of these cows will be destined for the plate.

It seems their main job here, apart from the obvious, is to make the most of the lush Spey grown grass.

-It's a lovely moment each year in the spring when they come out in the front field because the calves will be out for the first time and just see all this green grass, and they really don't know kind of what's going on.

And so you see them jumping around for joy.

It's -- It's fantastic.

-But it's not just bovine beauty Ballindaloch is renowned for.

♪♪ It's also home to one of the Spey's most beautiful and dramatic natural features.

♪♪ This is the Washing Machine.

♪♪ As the river is forced through a narrow channel in the bedrock here, the Spey almost appears to boil.

The resulting oxygen-rich waters attract salmon eager to rest on their long journey to spawn.

And where there are salmon on the Spey, there are fly-fishers.

-Yay!

-Yay!

He's never hooked a fish before, so it's a very exciting moment for all of us.

♪♪ -The pure, fast-flowing waters of the River Spey continue to take us eastward, towards one of the best salmon-fishing spots on the river.

♪♪ -I'm trying to keep my arms in the right position.

[ Both laugh ] -This is Dani Morey... -It is so much to think about.

-...who's made it her mission to bring fly-fishing to the masses.

-It's going well.

[ Both laugh ] I love teaching people to fish because...

I think everybody should have a chance to feel the way that I do every time that I walk down to this riverbank.

Flip it underneath.

That's it.

Now peel it 'round.

Slow.

[ Laughs ] -Ooh!

It's just a really addictive hobby, I suppose -- hobby-turned-job for me.

Set.

Well done.

-Salmon are notoriously difficult to catch, and the first thing any fly-fisher on the Spey needs is a fly to lure the fish.

-There's a little selection of flies.

These are the lady fishes here, which an awful lot of people have a lot of success with on the Spey.

-But, surprisingly, the purpose of these colorful flies isn't to tempt the salmon to eat.

-The fishing is just to actually aggravate them.

It's rather like a mother with small children constantly nip-nip-nipping.

Eventually, you do take the bait.

-But once you've got your fly, the knack is to cast it to where the fish are.

-That's it!

Now peel it back.

Well done.

I've got you.

-[ Laughs ] -Casting is a skill that can take years to master.

And on the Spey, since the 1800s, there's been a very particular way of doing it.

-Spey casting was developed so that you weren't constantly hooking up into trees and things.

-The trick is not letting the line go above your head so you catch a fish, not a tree.

-And the perfect Spey cast is just an art form.

It's beautiful.

It's poetry in motion, seeing that line sing out and land on the water.

-I love it.

♪♪ -With the end of the fishing season fast approaching, all along the river, anglers are desperately trying to bag a salmon.

And just upstream, one teenager has hit the jackpot.

♪♪ -How's your arm?

You getting sore?

-No.

It's just getting stiff now.

-He's never hooked a fish before, so it's very exciting moment for all of us.

Might well be the last fish that's hooked for the season because we're on to the last day now.

[ Reel whirring ] -Yay!

-Yay!

-It's just amazing.

-Wow!

Well done!

-How 'bout you?!

Well done!

Hey, well done, mate!

-We're going to end the season on a high now.

It couldn't have been better.

-A quick photo, a kiss goodbye, and the fish is returned to the water.

♪♪ -Hee hee!

Ha ha ha ha!

It's just amazing.

-Well done, Paul.

-Well done.

-As the anglers pack up and head home, the Spey is carrying us through the now quiet fishing estates.

Soon the autumn weather takes a turn... [ Thunder rumbles ] ...and the rain and mist bring out a different beauty in the river.

-I want to try and catch the -- not the miserable weather but just get a feel for what is not a sunny day.

-This ever-changing vista has drawn artist Graham Pook to an empty fishing bothy.

-And, of course, in Scotland... we have many of them -- not-sunny days.

-Graham moved to the Spey 20 years ago to paint.

♪♪ -It actually took me two years before I felt I was ready to paint it.

I felt I had to get to know it, to know the river.

I had to get to know the changing seasons.

And once I had got myself attuned to the rhythm of the light, then I felt I was ready to paint the Spey.

♪♪ This is quite a simple view.

Got the river... trees on the left here, and then the hill in the background, which is, since we've been here, it's now got a little bit of cloud coming over the top.

For me as an artist, it's about emotion, the subtle changes in my mood, and that's reflected in my painting.

I love this area.

It's gorgeous.

♪♪ -As we float away from the tranquil beauty of the fishing bothies, the Spey dramatically changes again as it heads into the Knockando Rapids.

♪♪ -It's so picturesque and then so flat, and then you've got this lovely bit of white water.

You have to be quite careful.

♪♪ You're reading the water.

You're always looking ahead as to where you're going to paddle, and then when you do get through these rapids, there's an excitement of -- of being surrounded by this foaming water, and it's immensely satisfying.

♪♪ -Once its waters calm, the river has another surprise in store.

♪♪ Hidden behind the pine trees are dozens of distilleries, producing half of all the whisky made in Scotland, and they've been built here, in the middle of a giant alluvial floodplain created by the Spey's nutrient-rich waters over millennia because its soil is perfect for growing barley.

♪♪ And it's barley that makes the malt that makes the whisky so special here.

And for some, getting a taste of whisky in a real Speyside pub can be a life-changing experience.

-£7.70, please.

-This is Tatsuya Minagawa.

-I've been here 20 years, but I don't pick up much Scottish accent, so still I can say, "I am from Japan."

-Thank you.

-Tatsuya has become something of a local celebrity.

A barman in Kyoto, Japan, he came to the Spey to find out more about his favorite tipple, and he landed a job in this pub.

-Malt, and this is blended, so...

I used to work for previous owner for 10 years, and he decided to sell.

Luckily, very kind -- Royal Bank of Scotland lent me money [Chuckles] so I could purchase it.

[ Chuckles ] -Not surprisingly, Tatsuya is a bit of an expert when it comes to whisky, and, for him, the global success of the Scottish whisky industry is down to the unique taste of the Speyside whiskies made around here.

[ Squeaks, pops ] -Scotland currently the biggest whisky producer and especially in Speyside.

Around 50 working distilleries -- the biggest whisky-producing region.

So, yeah, something special, and tastewise, it's -- I can describe like a fragrant, subtle, gorgeous.

-But if you ask him which one's his favorite, he's only got one answer.

-I always say, "Any whiskey you buy me."

[ Laughs ] -But, alas, it's time we got off the hard stuff and back onto the water.

The Spey is just beginning its final descent to the North Sea, and it's sweeping us towards an extraordinary engineering phenomenon.

-Just an amazing structure.

We get tourists coming from all over the world to pay homage to this.

♪♪ -144 kilometers into its journey, the Spey is far from tired.

The closer we come to the sea, its clear waters begin to pick up the pace.

-Good afternoon!

Lady Spey stays really very lively all the way to the to the sea, to the Moray Firth.

-But before we reach the natural beauty of Spey Bay, the river is carrying us towards a stunning man-made marvel.

-We're now coming to my favorite bridge on the Spey.

♪♪ ♪♪ -This wonder of the Industrial Age is the great Craigellachie Bridge.

With its graceful single-iron span soaring 46 meters across the river, when it was completed in 1814, no one had seen anything quite like it.

♪♪ The brainchild of Scottish architect Sir Thomas Telford, it's considered to be a masterpiece of structural engineering that puts it on a par with the Golden Gate Bridge.

-Just an amazing structure.

We get tourists coming from all over the world to pay homage to this.

-Locals Neil Fotheringham and George Cordiner are the bridge's biggest fans.

-Never ceases to amaze me that that was put together before there was cranes.

It was all done by hand.

-Constructed using 183 tons of prefabricated cast iron sections bolted together to create its four slender arches, the bridge took just two years to complete.

-It is an inspiring structure when you think about the time that it was constructed.

To build this for £8,200, it's a bargain.

♪♪ -Telford's revolutionary design became the blueprint for thousands of cast iron bridges across the globe.

-From an engineering point of view, it's really good when you get underneath.

It's the oldest surviving bridge of its type left in the U.K. For its age, it is in very good condition, apart from the paintwork.

-I mean, it's a testament to the design, the fact it's still here over 200 years when many other bridges have been washed away.

♪♪ -Even in full flood, the mighty Spey hasn't been able to defeat Telford's masterpiece, and today it remains one of the greatest and most influential engineering feats of the 19th century.

-It's just an iconic structure -- I think just the shape and the setting of it -- and it's just a beautiful bridge.

♪♪ -Heading towards the estuary, the Spey takes on a renewed urgency.

As its swirling waters carry us under the old railway bridge, an extraordinary new landscape is revealed.

♪♪ Filled with an ocean of stone and ancient Scots pines carried down from the distant Cairngorm Mountains, this is where the Spey meets the North Sea.

[ Gulls crying, waves crashing ] ♪♪ And here at Spey Bay, a poignant reminder of the river's past is frozen in time.

♪♪ This is the Tugnet Ice House.

♪♪ For more than 200 years, it was the center of the Spey's salmon-fishing industry.

-This is very important for the fish.

-Jim Gordon is one of the last to remember working here during its heyday in the 1960s.

-I was here for 44 years, and my father worked here, his father, and his father.

-Back then, just as they'd done for centuries before, salmon were caught by the hundreds using nets strung across the river.

To keep the fish fresh, they were still relying on ice harvested from local ponds.

-Up there was where the horse and cart would have come and tipped it in.

There could have been maybe 40, 60, 100 tons of ice in here.

-To preserve the ice, 2/3 of this massive structure is underground, and it was from here the fish would be sent to market twice a week.

-Those boxes here for big salmon would be moved to London.

Salmon-fishing was an interest to everybody at that time because it was one of the main employers here.

-By the 1990s, when the salmon numbers began to plummet, the fishing industry here came to an end.

But it proved to be a new beginning for the River Spey.

♪♪ -It's a special place for me.

I love walking down the beach there.

There's lots and lots of different birds and things here nowadays.

♪♪ Thousands and thousands of people come here, summer or winter, and just enjoy the wildlife.

♪♪ This is the most beautiful place to come -- a majestic river, I would say.

♪♪ -The stunning beauty of Spey Bay is a fitting end to our journey that began 160 kilometers away, high in the Cairngorm Mountains.

♪♪ Along the way, we've seen how the Spey has shaped almost every aspect of life here.

♪♪ And today, the river is famed for its salmon-fishing and whisky production.

But as we've discovered on our voyage, what makes the Spey truly special is that throughout its long history, it's remained wild, pure, and untouched.

♪♪ ♪♪ ♪♪