0:00:10 > 0:00:15It's good to see ourselves as others see us.
0:00:18 > 0:00:2120 miles or so over there is Dover.
0:00:21 > 0:00:25This is the view of our coast from France.
0:00:25 > 0:00:30We're in Northern France - one small step from Britain,
0:00:30 > 0:00:34one giant leap in language and culture.
0:00:34 > 0:00:37We're not on our island any more - this is mainland Europe.
0:00:39 > 0:00:41Niggly neighbours we may be,
0:00:41 > 0:00:45but there's an unbreakable bond between our coasts.
0:00:45 > 0:00:50Our shared story is written into the landscape
0:00:50 > 0:00:52and it runs in our blood.
0:00:52 > 0:00:57From Norman conquest to the D-Day liberation,
0:00:57 > 0:01:00a narrow stretch of sea can't separate us.
0:01:02 > 0:01:06Now we're following the threads that tug us time and again across the Channel.
0:01:09 > 0:01:14And here to meet our French neighbours are the usual familiar faces.
0:01:14 > 0:01:20Mark Horton discovers why it was French stone that built England's first castles.
0:01:20 > 0:01:23That's completely exhausting!
0:01:23 > 0:01:26Alice Roberts is trying to make a good impression.
0:01:26 > 0:01:29It's still nerve-wracking.
0:01:29 > 0:01:35Miranda Krestovnikoff is throwing some light on the private life of bats.
0:01:36 > 0:01:43On a voyage of discovery to an underwater wonderland, Nick Crane is on the French Channel Islands.
0:01:43 > 0:01:48I had no idea that there was such a huge landmass lurking beneath the waves.
0:01:48 > 0:01:55And Dick Strawbridge explores a secret map that saved D-Day from sinking in the sand.
0:01:55 > 0:01:58The old halftrack is getting through there, all right!
0:01:58 > 0:02:02This is our coast, and beyond.
0:02:28 > 0:02:32We've crossed the English Channel, heading for Mont-St-Michel.
0:02:32 > 0:02:37Our French odyssey begins at Cap Gris Nez - or the Grey Nose -
0:02:37 > 0:02:40where France is within sniffing distance of England.
0:02:44 > 0:02:50Standing on this spot, I'm full of anticipation for our journey along the French coast.
0:02:52 > 0:02:57But others have come here to look back at our coast, with conquest in mind.
0:02:57 > 0:03:04In 1803, Napoleon eyed up the south coast for invasion, but was held back by the Royal Navy.
0:03:06 > 0:03:11Nearly 140 years later it was Hitler who was headed off by the Royal Air Force,
0:03:11 > 0:03:15but there are traces of his tyranny left behind.
0:03:15 > 0:03:19The footprints of the German army are still deeply embedded along this shore,
0:03:19 > 0:03:26but what I find intriguing is that this World War II bunker is built on top of a much earlier fort,
0:03:26 > 0:03:28a fort that was put here by Henry VIII.
0:03:30 > 0:03:34The earthworks of defensive ditches and mounds still dominate Hitler's bunkers.
0:03:34 > 0:03:40Henry VIII's fort was built in 1546, but its shape still scars the landscape,
0:03:40 > 0:03:44a quarter of a mile across from ditch to ditch.
0:03:46 > 0:03:50Not that there's much left of the walls built into these earthworks.
0:03:50 > 0:03:57Daniel Leunens, who's written a history of this coast, is showing me one tantalizing glimpse.
0:03:57 > 0:03:59Right, fantastic.
0:03:59 > 0:04:03So this is 16th century masonry?
0:04:03 > 0:04:06That's right, yes. And this is the entrance of some rooms,
0:04:06 > 0:04:10where were stored lots of things -
0:04:10 > 0:04:12gunpowder...and beer.
0:04:12 > 0:04:15- Beer?- Much more beer than wine, anyway!
0:04:15 > 0:04:18- Right, how very English!- Ah!
0:04:19 > 0:04:26In Henry VIII's day, this WAS England, a last toe-hold on the continent.
0:04:26 > 0:04:29Nearby Calais was at the heart of an English enclave,
0:04:29 > 0:04:32a remnant of the former territory in Northern France, and the fort,
0:04:32 > 0:04:38inspired by a cutting-edge Italian design, was intended to bolster their position.
0:04:38 > 0:04:44Henry clearly planned to stay, he was even going to build a new port around the Cap.
0:04:46 > 0:04:52To defend this harbour he needed a fort, but the harbour should never be made.
0:04:52 > 0:04:56So they built the defences, but didn't build the thing the defences were here to defend?
0:04:56 > 0:04:58That's right, yeah.
0:05:00 > 0:05:04The English clung onto this coast for another 12 years,
0:05:04 > 0:05:07before being finally booted back across the Channel.
0:05:07 > 0:05:12One more spat in a barney that's rumbled on along this shore
0:05:12 > 0:05:16between battling siblings either side of the sea.
0:05:16 > 0:05:21Connections between Britain and France are the story of this coast,
0:05:21 > 0:05:25links across the sea that we'll explore along our journey.
0:05:32 > 0:05:37As well as clashing, we've been comfortable coming together, too.
0:05:37 > 0:05:41In the 1920s, London's smart set would think nothing of hopping
0:05:41 > 0:05:46on a plane to fly directly to the fashionable resort of Le Touquet.
0:05:49 > 0:05:51There's a lot about this coastline to make us feel at home,
0:05:51 > 0:05:54and at the bracing seaside town of Ault,
0:05:54 > 0:05:57the weather isn't the only thing we've got in common.
0:06:01 > 0:06:07Nick is getting to grips with foreign terrain which feels strangely familiar.
0:06:07 > 0:06:12Think of a coastal landmark that symbolises Britain.
0:06:12 > 0:06:17We write songs about them, we treat them as one of our national icons.
0:06:17 > 0:06:18But think again.
0:06:18 > 0:06:22Welcome to the White Cliffs of France.
0:06:24 > 0:06:31I don't know if bluebirds fly over these white cliffs, but they do stretch for almost 150 miles.
0:06:31 > 0:06:35They certainly look familiar, but is the similarity more than skin deep?
0:06:37 > 0:06:41I'm meeting geologist Rory Mortimore.
0:06:41 > 0:06:47He's a man who can tell if this chalk has the same fingerprint as the English cliffs.
0:06:47 > 0:06:53Strangely, though, it's not the chalk itself that we're looking at, but what's embedded in it.
0:06:53 > 0:06:56You see these black nodules?
0:06:56 > 0:06:58These are lumps of flint,
0:06:58 > 0:07:05- and this flint has formed around animal burrows into the seabed.- OK.
0:07:05 > 0:07:09But what is fantastic about the way that the flint forms
0:07:09 > 0:07:13is that it's unique at every level in the chalk.
0:07:13 > 0:07:18- So at this level you'll see they are tubular.- Is that one there?
0:07:18 > 0:07:20- It is. - That's the outside of a tube, there.
0:07:20 > 0:07:23When you follow this across the whole of the English Channel area
0:07:23 > 0:07:28where the chalk is present, you can identify this layer because of its tubular flint.
0:07:28 > 0:07:34- And this sample is of the tubular flint which was collected on the Isle of Wight.- Isn't that amazing?
0:07:34 > 0:07:38So your bit of tubular flint from Southern England matches up this bit of tubular flint here?
0:07:38 > 0:07:40It does indeed, matches perfectly.
0:07:42 > 0:07:48Which means the chalk on both sides of the Channel was laid down at the same time.
0:07:48 > 0:07:50In fact it's still there, under the sea.
0:07:50 > 0:07:55For millions of years, we were all part of the same landmass.
0:07:55 > 0:08:00There was no England or France, and certainly no Channel.
0:08:02 > 0:08:06If you were here, say, 600,000 years ago, you'd have been able to walk
0:08:06 > 0:08:10on chalk downland all the way from here to England.
0:08:10 > 0:08:13- All the way across there? - All the way across the Channel.
0:08:13 > 0:08:17- The chalk downs ran from here, undulating, all across the South Downs?- Yes.
0:08:17 > 0:08:18Gow was the Channel formed?
0:08:18 > 0:08:25By a cataclysmic geological event, Nick, a very spectacular event - what we call a megaflood.
0:08:26 > 0:08:29That megaflood started as a trickle
0:08:29 > 0:08:33through a chalk ridge that spanned the Channel.
0:08:33 > 0:08:37This ridge was holding back a colossal lake, fed by melt water
0:08:37 > 0:08:44from glaciers across Northern Europe, and soon to become the North Sea.
0:08:44 > 0:08:47When the chalk gave way, it was catastrophic.
0:08:50 > 0:08:52It must have been a very extraordinary event,
0:08:52 > 0:08:57a very dramatic event, and would have happened in a very short space of time.
0:08:57 > 0:09:01That would have isolated Britain from Europe for the very first time.
0:09:01 > 0:09:06- And how deep is the Channel now? - The Channel is surprisingly shallow.
0:09:06 > 0:09:09This point is perhaps 30 metres deep.
0:09:09 > 0:09:13If you were to imagine taking something like St Paul's Cathedral,
0:09:13 > 0:09:17put it on the floor of the English Channel here, most of it would be sticking out.
0:09:17 > 0:09:20It's a very shallow sea.
0:09:23 > 0:09:30Our shores might be separated by the sea, but we share the same problem - erosion.
0:09:30 > 0:09:34Dover's cliffs are crumbling, but because of the way the tides
0:09:34 > 0:09:38course through the Channel, the situation here is even worse.
0:09:38 > 0:09:43Almost half a metre a year of coast is lost to the sea.
0:09:43 > 0:09:48In the town of Ault, they've been battling it for centuries.
0:09:48 > 0:09:50Now, this photograph was taken just a few decades ago.
0:09:50 > 0:09:55The building on the left here is that cream building down there,
0:09:55 > 0:10:01and here is a very beautiful crazy golf course. But just look at this.
0:10:02 > 0:10:04This is where the golf course was.
0:10:06 > 0:10:13You can't actually fight this sort of erosion, so in Ault they've stopped trying.
0:10:13 > 0:10:18Instead of building more sea defences they're going to build a new town,
0:10:18 > 0:10:23or rather an extension to the existing one - 400 metres inland.
0:10:25 > 0:10:30The primal forces that carved out the Channel are also eating up the coast.
0:10:30 > 0:10:36We can't stop it so, like the French, we'll have to learn to live with it.
0:10:51 > 0:10:56Just as the elemental forces batter this coast, they can also be strangely uplifting.
0:10:57 > 0:11:02In Dieppe, they positively revel in the brisk sea breezes.
0:11:07 > 0:11:11And they celebrate them with colourful paper and steel,
0:11:11 > 0:11:14canvas and string.
0:11:17 > 0:11:23The city's kite festival happens every two years, and thousands turn up to join in.
0:11:30 > 0:11:33While most are happy to keep their feet on the ground,
0:11:33 > 0:11:37others look to their kites for a thrill - a jump-start, even.
0:11:39 > 0:11:43My name is Pierre Cardineaud. I'm the world champion kite jumper.
0:11:47 > 0:11:49You look good for a few seconds.
0:11:51 > 0:11:5483 metres is the world record,
0:11:54 > 0:11:58and over nine metres in height.
0:11:58 > 0:12:03There is not enough wind to do a big jump. You can do freestyle,
0:12:03 > 0:12:07for example two or three...twists.
0:12:11 > 0:12:13It's not to fly, really.
0:12:13 > 0:12:16It is a little fly on the jump,
0:12:16 > 0:12:21like a fish in the sky or like a bird who is going to... Just a small jump.
0:12:23 > 0:12:2620, 30 metres later along...
0:12:26 > 0:12:28puff!
0:12:28 > 0:12:31It is that that I love.
0:12:44 > 0:12:48The French know a thing or two about revolutions,
0:12:48 > 0:12:52and this coast started one that spread around the globe.
0:12:56 > 0:13:01Amateur artist Alice Roberts has packed her paints, heading
0:13:01 > 0:13:07for Etretat to explore how this shoreline made a lasting impression on the world of art.
0:13:12 > 0:13:15The place I'm looking for is just down here.
0:13:17 > 0:13:20Even though I've never been here before, I feel like I know this
0:13:20 > 0:13:27particular spot in Normandy very well - from paintings I studied back in school.
0:13:28 > 0:13:31And this is what I've been looking for.
0:13:34 > 0:13:40La Porte d'Aval. It's been described as an elephant dunking its trunk in the sea.
0:13:40 > 0:13:45It's one of the most photographed sites in France, and one of the most painted.
0:13:48 > 0:13:54And it's this painting that's brought me here, Cliffs of Etretat, 1883
0:13:54 > 0:13:59by Claude Monet, the father of Impressionism.
0:13:59 > 0:14:05Impressionist painting was a revolutionary way of capturing colour and light on canvas,
0:14:05 > 0:14:10and it all started here on this coastline around 135 years ago.
0:14:13 > 0:14:16Unlike many artists of the day, the Impressionists shunned
0:14:16 > 0:14:22the comfort of the studio and worked outdoors to experience the elements.
0:14:24 > 0:14:28Photography was becoming popular, but these artists were trying
0:14:28 > 0:14:34to capture light in a different way, experimenting with oil painting.
0:14:34 > 0:14:40I want to see what it is about Normandy that inspired the Impressionists,
0:14:40 > 0:14:44and I'm hoping that British artist Rob Perry can help me.
0:14:44 > 0:14:48For the last 15 years, Rob's been coming to France to paint.
0:14:48 > 0:14:50- Hi, Alice. Nice to meet you. - How are you?
0:14:50 > 0:14:54'He's going to give me a hands-on introduction to Impressionism,
0:14:54 > 0:14:57'but we've got to hurry.'
0:14:57 > 0:15:03- Let's go for it. - 'It's late in the afternoon with the daylight fading fast.'
0:15:03 > 0:15:08Monet worked in the moment with nature's changing moods.
0:15:10 > 0:15:15He'd cope in all conditions, maybe even nursing a cold, like me.
0:15:15 > 0:15:21- Setting up our easels outside, this is exactly how the Impressionists painted, isn't it?- Exactly, yes.
0:15:21 > 0:15:23They were able to do it, of course,
0:15:23 > 0:15:26because of the invention of the tube for oil paints.
0:15:26 > 0:15:28They didn't have to mix them up with pestles and mortars
0:15:28 > 0:15:30like they had in previous centuries.
0:15:30 > 0:15:33- So new technology freed them to go outside?- Absolutely, yes.
0:15:33 > 0:15:36Rob, I really want to get the texture of the sea.
0:15:36 > 0:15:39- That is the rocks we're looking at, and I love this sea.- Yeah.
0:15:39 > 0:15:43The Impressionists loved to get this kind of vibrant paint surface,
0:15:43 > 0:15:49- made of flecks of different colours. - And this is going to change as we paint it, isn't it?- Oh, yes.
0:15:49 > 0:15:52You've got to work fairly quickly when you're working on the spot.
0:15:52 > 0:15:55Monet always worked in very broad touches, you see.
0:15:55 > 0:15:58They used these short stabbing brushstrokes, you know?
0:15:58 > 0:16:01You hold it like an axe, really.
0:16:01 > 0:16:03OK, that's a good tip.
0:16:03 > 0:16:07The Impressionists broke with many conventions of the day.
0:16:07 > 0:16:11They'd rarely start a painting with an outline sketch -
0:16:11 > 0:16:15instead they put colour straight onto the canvas, freehand.
0:16:15 > 0:16:17It makes me nervous working this quickly.
0:16:17 > 0:16:19- We've got 20 minutes.- OK.
0:16:22 > 0:16:25They didn't believe in mixing colours on the palette.
0:16:25 > 0:16:29They applied it pure, as it came out of the tube.
0:16:31 > 0:16:36Hmm... 'I'm beginning to see the challenge of Impressionist painting.'
0:16:36 > 0:16:43I simply can't work fast enough to get all these changes of light onto the canvas, and before we know it
0:16:43 > 0:16:46the light's gone altogether.
0:16:46 > 0:16:50We'll have to give it another try tomorrow.
0:16:56 > 0:17:02But before we do, I want to visit the place that first inspired this new artistic movement -
0:17:02 > 0:17:05the bustling harbour town of Le Havre.
0:17:06 > 0:17:09Monet grew up around here,
0:17:09 > 0:17:14and in 1872, he painted this view of the harbour at dawn.
0:17:14 > 0:17:19He called it Impression Sunrise, and so coined the term for a completely
0:17:19 > 0:17:23new way of looking at the world - Impressionism.
0:17:25 > 0:17:30I'm hoping French art historian Emanuelle Riand can tell me more.
0:17:31 > 0:17:35So this is the really famous painting, isn't it?
0:17:35 > 0:17:39Yes, the first Impressionist painting. It can be said,
0:17:39 > 0:17:42he did it from his window,
0:17:42 > 0:17:46it was his direct view on the harbour.
0:17:46 > 0:17:48And was it well received at the time?
0:17:48 > 0:17:50No, because it was very different.
0:17:50 > 0:17:53It was probably not...
0:17:53 > 0:17:57well drawn enough for them, and too much coloured.
0:17:57 > 0:18:00It was very shocking for this time.
0:18:00 > 0:18:05What's shocking for me is the speed at which Monet painted.
0:18:05 > 0:18:08In one session, he could work on 10 canvases,
0:18:08 > 0:18:11and I struggled with one in an afternoon.
0:18:11 > 0:18:13I'm determined to have another go.
0:18:16 > 0:18:19So the first challenge here is to put this easel up in this wind,
0:18:19 > 0:18:23so I've hung a bag with some heavy pebbles in it off the easel.
0:18:23 > 0:18:26Now I've just got to choose some colours.
0:18:26 > 0:18:31It's still quite grey, so I'm going to have to get my Impressionist eye working.
0:18:31 > 0:18:35And in those greys I think I can see some purples in that cliff,
0:18:35 > 0:18:37maybe some yellow colours.
0:18:37 > 0:18:40Let's have a splurge of that one.
0:18:40 > 0:18:43Rob's painting as well, but in his own style.
0:18:43 > 0:18:50Although he works outdoors, he isn't exactly an Impressionist as Monet would have recognised.
0:18:52 > 0:18:54It's still nerve-wracking.
0:18:59 > 0:19:02He's getting the colour onto the canvas as quickly as possible,
0:19:02 > 0:19:09but I'm sticking to the Impressionist rules - separate strokes to create an impression of colour.
0:19:18 > 0:19:21It's just mad, cos the light changes all the time as well.
0:19:21 > 0:19:24You're here for three hours and you pick the bits that you like.
0:19:24 > 0:19:27You wait for the sky to change, and you think, "Oh, I like that."
0:19:35 > 0:19:39- What do you think, Rob?- You've got some really nice colour in there.
0:19:39 > 0:19:43That's exactly what the Impressionists were after. The sky has come out very well.
0:19:43 > 0:19:45I think I'm most pleased with the sky.
0:19:45 > 0:19:47I really struggled with the sea.
0:19:47 > 0:19:51And it's that elusive quality of light in the sea and the sky
0:19:51 > 0:19:54that must have so fascinated the Impressionists,
0:19:54 > 0:19:59drawing them back to this coast time and time again.
0:20:06 > 0:20:10At Le Havre, a huge gash opens up in the coast.
0:20:10 > 0:20:14This is where the sea meets one of the world's mightiest rivers -
0:20:14 > 0:20:15the Seine.
0:20:17 > 0:20:20A great river demands a great bridge,
0:20:20 > 0:20:24and the Pont de Normandie rises to the occasion.
0:20:24 > 0:20:27Seven years in the making,
0:20:27 > 0:20:29184 steel cables suspend the road over the river.
0:20:29 > 0:20:33That's the left bank of the River Seine down there.
0:20:33 > 0:20:37Travel about 120 miles in that direction
0:20:37 > 0:20:41and you arrive in the famous artistic district of Paris.
0:20:41 > 0:20:45But there's another little artistic gem on the left bank of the Seine.
0:20:47 > 0:20:52In Honfleur, even the boat builders have an artistic flair.
0:20:54 > 0:20:56Their craft helped see off the English
0:20:56 > 0:20:58during the Hundred Years War.
0:21:03 > 0:21:05When peace was finally declared,
0:21:05 > 0:21:09the boat builders of Honfleur used their skills to build a church,
0:21:09 > 0:21:11a wooden church.
0:21:13 > 0:21:15Started in the 1460s,
0:21:15 > 0:21:19its roof reflects its maritime heritage...
0:21:21 > 0:21:23..Looking like the upturned hull of a ship.
0:21:32 > 0:21:36Oddly, the bell tower is built separately,
0:21:36 > 0:21:40maybe to protect the wooden church against lightning strikes,
0:21:40 > 0:21:43or perhaps the vibration of the bells. No-one's quite sure.
0:21:47 > 0:21:50Honfleur has witnessed a steady stream of traffic
0:21:50 > 0:21:52crossing the Channel for centuries.
0:21:54 > 0:21:57But in 1066, thanks to William the Conqueror,
0:21:57 > 0:21:59it was all heading in our direction.
0:22:03 > 0:22:06Invasion came as second nature to these Normans.
0:22:06 > 0:22:09After all, originally they were Norsemen,
0:22:09 > 0:22:13Viking marauders who'd only been in France 150 years
0:22:13 > 0:22:15before they turned their sights on us.
0:22:15 > 0:22:19But they left a permanent legacy in stone.
0:22:20 > 0:22:24The Normans taught us their tradition of castle construction,
0:22:24 > 0:22:26bringing it to Britain.
0:22:26 > 0:22:30Among their first big builds, the Tower of London,
0:22:30 > 0:22:35and Canterbury Cathedral, and they built them with French stone.
0:22:36 > 0:22:39In the heart of Normandy, Mark Horton is on his way
0:22:39 > 0:22:42to the city of Caen
0:22:42 > 0:22:46in search of that special stone worthy of William's English castles.
0:22:49 > 0:22:52In the years after 1066,
0:22:52 > 0:22:56the River Orme, that connects Caen to the sea,
0:22:56 > 0:22:58would be busy with Norman longboats like this,
0:22:58 > 0:23:04transporting great blocks of stone to Britain for building.
0:23:04 > 0:23:11Medieval castle expert Pamela Marshall and I are retracing the route to try and discover why.
0:23:11 > 0:23:14Caen stone is one of the best.
0:23:14 > 0:23:18And I know it seems a long way from England, but he's got this waterway.
0:23:18 > 0:23:24He then just whips it across the sea across the Thames, and it's a material that his craftsmen
0:23:24 > 0:23:28are well-versed with, they know how to use it.
0:23:28 > 0:23:32And he presumably thinks the Anglo Saxon masons are rubbish, anyway?
0:23:32 > 0:23:36Possibly. Remember, the Anglo Saxons aren't used to castles at all,
0:23:36 > 0:23:37let alone stone ones.
0:23:44 > 0:23:49William not only had a mighty river to transport the stone,
0:23:49 > 0:23:53but at Caen, he had a ready supply, right beneath his feet.
0:23:54 > 0:23:58The city was built on limestone,
0:23:58 > 0:24:02a rare limestone containing very few fossils.
0:24:02 > 0:24:05Having used it for castles and cathedrals here,
0:24:05 > 0:24:09William was determined to bring it to England.
0:24:11 > 0:24:15Hidden beneath the streets of modern Caen, there's still a labyrinth
0:24:15 > 0:24:20of ancient stone quarries, abandoned since the Middle Ages.
0:24:20 > 0:24:25We've come to one tucked away in a quiet corner of the city.
0:24:25 > 0:24:29It's only accessible, we're told, because the roof collapsed,
0:24:29 > 0:24:31creating a makeshift entrance.
0:24:37 > 0:24:41Inside, it's as if the workers had left yesterday.
0:24:45 > 0:24:48Look at this, that's where the chariot, the wagon has...
0:24:48 > 0:24:50- The wagon has brushed past it! - Has brushed past it.
0:24:52 > 0:24:56Oh, these are fantastic. To split the rock away,
0:24:56 > 0:24:59they cut out a wedge shape with chisels
0:24:59 > 0:25:04and then insert a dry wooden wedge, which they then wet.
0:25:04 > 0:25:09And as the wood expands, it helps the rock to split naturally.
0:25:09 > 0:25:11It's extraordinary, it's like a frozen moment in time.
0:25:11 > 0:25:14Yes, absolutely.
0:25:14 > 0:25:18But what was it about the stone that made it so special?
0:25:20 > 0:25:23Worth hauling across the Channel?
0:25:23 > 0:25:26Who better to ask than a group of modern Norman masons?
0:25:28 > 0:25:35Jean Pierre Dauxerre, a former city planner, is passionate about Caen stone.
0:25:35 > 0:25:41It's a stone we like to stroke with eyes, with hands.
0:25:41 > 0:25:44- Is it possible to break it open? - Yes, it is.
0:25:44 > 0:25:47Seconde, troisieme.
0:25:48 > 0:25:51- Here we go.- Do it slow. Slowly.
0:25:54 > 0:25:58- Give it some welly, shall we? Hey!- Bravo!
0:26:00 > 0:26:03- Voila, you are strong. - I know! Isn't that amazing?!
0:26:03 > 0:26:07- Just a few pieces like this, and look what happens.- It's your work.
0:26:07 > 0:26:10There are no fossils or anything in it.
0:26:10 > 0:26:13It's the colour of churches, castles.
0:26:13 > 0:26:18But the stone now is so soft, just falls apart in one's hands.
0:26:18 > 0:26:24Stone becomes hard because water...goes away.
0:26:24 > 0:26:27- Evaporates from it.- Evaporates, yes.
0:26:27 > 0:26:29C'est parti!
0:26:29 > 0:26:32The stone is quite soft when extracted,
0:26:32 > 0:26:36easy to split or cut using even the most basic tools.
0:26:36 > 0:26:42And the longer it's exposed to the air, the tougher it gets.
0:26:42 > 0:26:45That's completely exhausting!
0:26:45 > 0:26:50And without shells or fossils to make it fracture unpredictably,
0:26:50 > 0:26:53it can also be finely worked,
0:26:53 > 0:26:58which is why it was highly-prized amongst Medieval masons.
0:27:00 > 0:27:03The Normans helped shape Britain,
0:27:03 > 0:27:09they laid the foundations for some of our greatest buildings.
0:27:09 > 0:27:11Although these structures have been extended since,
0:27:11 > 0:27:16there's a little bit of Normandy left in most of them.
0:27:35 > 0:27:41This is a coast that has known invading armies depart and arrive.
0:27:41 > 0:27:46The tranquil stretches of sand give few clues to the turbulent role they played in our recent history.
0:27:51 > 0:27:53But on the 6th June 1944,
0:27:53 > 0:27:58156,000 Allied servicemen landed here.
0:27:59 > 0:28:02These are the D-Day beaches.
0:28:05 > 0:28:08This wasn't the most obvious or the easiest place to launch
0:28:08 > 0:28:11a massive invasion of mainland Europe,
0:28:11 > 0:28:15which is precisely why these beaches were chosen.
0:28:16 > 0:28:19The most obvious place to unload tanks and heavy equipment
0:28:19 > 0:28:23was somewhere built for the job, a port like Dieppe.
0:28:25 > 0:28:29But when the Allies did try to land here in 1942, it ended in disaster.
0:28:30 > 0:28:33The Germans had fortified the place.
0:28:33 > 0:28:36Canadian and British forces lost over 3,000 men.
0:28:39 > 0:28:42It was clear that for a successful invasion,
0:28:42 > 0:28:46the Allies would have to arrive where the Germans didn't expect them.
0:28:48 > 0:28:53But the British knew the terrible price of trying to fight their way off a beach.
0:28:55 > 0:29:01During the First World War, the Allies had attempted to land on the beaches of Gallipoli in Turkey.
0:29:01 > 0:29:05Over 100,000 men were killed or wounded
0:29:05 > 0:29:11before the mission was abandoned, and a generation of soldiers learned to fear landings on sand.
0:29:13 > 0:29:16Former army engineer Dick Strawbridge is exploring
0:29:16 > 0:29:20how the Allies prepared for the biggest seaborne assault in history.
0:29:23 > 0:29:27The D-Day planners were haunted by the disaster of Gallipoli,
0:29:27 > 0:29:31but the beach invasion they were planning would dwarf that operation.
0:29:34 > 0:29:37The aim this time was to overwhelm the enemy at high speed,
0:29:37 > 0:29:40using tanks and other armoured vehicles,
0:29:40 > 0:29:43but the Allies' worry was that they'd get bogged down.
0:29:45 > 0:29:49Even with some ruts on the sand, the old half-track is getting through there all right.
0:29:51 > 0:29:54So rough-packed sand isn't a big problem.
0:29:56 > 0:30:00It wasn't necessarily the sand they were worried about,
0:30:00 > 0:30:03it was what was underneath it that the Allies were concerned about.
0:30:03 > 0:30:06This whole area is riddled with soft, sticky peat bogs
0:30:06 > 0:30:08lurking below the surface.
0:30:10 > 0:30:15The sand may appear very smooth, able to support the vehicle's weight, or even mine.
0:30:17 > 0:30:20OK, feels nice and solid.
0:30:20 > 0:30:23But dig a little deeper and it's a different story.
0:30:23 > 0:30:27What have we got? Oh, it's a different colour, completely different colour.
0:30:29 > 0:30:32That's a peat bog, being an Ulsterman, I should know about those things.
0:30:32 > 0:30:37That is peat, which mean there's definitely no way you'd bring your vehicles over this bit.
0:30:37 > 0:30:40There's an awful lot to do to cover this beach.
0:30:43 > 0:30:50These peat bogs are the remains of ancient forests submerged when the Channel flooded.
0:30:50 > 0:30:53From the air, it's possible to see them as dark patches.
0:30:53 > 0:30:57What you can't see are the ones underneath the sand.
0:30:57 > 0:31:02Trials on similar beaches in Norfolk had shown that peat had the potential
0:31:02 > 0:31:06to bring the invasion to a grinding halt.
0:31:06 > 0:31:09Allied intelligence had to identify these areas,
0:31:09 > 0:31:13and they had to do so without alerting the Germans.
0:31:14 > 0:31:17They used any information they could get their hands on -
0:31:17 > 0:31:21old holiday snaps, ancient maps, medieval accounts -
0:31:21 > 0:31:25to build a picture of the terrain that lay beneath the surface.
0:31:25 > 0:31:27This is what it was all about,
0:31:27 > 0:31:32a map of the potential hazards of this beach that was codenamed Gold by the Allies.
0:31:32 > 0:31:35Look here, it's dated March 1944.
0:31:35 > 0:31:40On the top it says "BIGOT", that's a classification beyond Top Secret used especially for D-Day.
0:31:40 > 0:31:45You can see areas here where there's possibly pools that are clay, and they move and change shape,
0:31:45 > 0:31:48but the details here, people have made this really accurately.
0:31:48 > 0:31:50If you're going to attack this beach,
0:31:50 > 0:31:52you need to understand where not to be.
0:31:52 > 0:31:56This sort of detail couldn't be gathered from a distance.
0:31:56 > 0:32:01Someone had to get onto the beach itself and take samples of the sand,
0:32:01 > 0:32:03right in front of the Germans.
0:32:03 > 0:32:11At just 23 years old, Major Logan Scott-Bowden found himself leading this vital mission.
0:32:11 > 0:32:15He and fellow Royal Engineer Sergeant Bruce Ogden-Smith would be
0:32:15 > 0:32:20the first troops to land here, unsupported and six months ahead of D-Day.
0:32:23 > 0:32:27These days, it's difficult for Major General Scott-Bowden to travel,
0:32:27 > 0:32:30so I've come to see him.
0:32:30 > 0:32:34- Sir, lovely to meet you. - Very nice to see you, Dick.
0:32:34 > 0:32:37But first, a small gift from the beaches of Normandy.
0:32:40 > 0:32:41What do you think of that?
0:32:41 > 0:32:44Ha! Well, I never!
0:32:44 > 0:32:46Sand, and the peat layer, just below the sand.
0:32:46 > 0:32:49- Yes.- Does that bring back memories?
0:32:49 > 0:32:52Yes, it does indeed.
0:32:52 > 0:32:57Major General Scott-Bowden collected his sand sample drilling with a metal auger like I did,
0:32:57 > 0:33:01but he had to swim ashore with his at night
0:33:01 > 0:33:04and take the samples from within feet of enemy patrols.
0:33:07 > 0:33:11The mission was timed for the stroke of midnight, New Year's Eve 1943,
0:33:11 > 0:33:14on orders from the highest authority.
0:33:14 > 0:33:18Churchill said, "Well, they'll all be celebrating on New Year's Eve,
0:33:18 > 0:33:20"they won't be patrolling very much.
0:33:20 > 0:33:22"It's a good opportunity."
0:33:22 > 0:33:25We were doing the job on a rising tide,
0:33:25 > 0:33:28which would obscure our tracks,
0:33:28 > 0:33:32but of course one thing we hadn't reckoned on was the time difference.
0:33:32 > 0:33:39They were an hour ahead of us and these Germans were clearly...
0:33:39 > 0:33:44well on in their New Year celebrations,
0:33:44 > 0:33:46so we didn't expect any trouble from them.
0:33:46 > 0:33:50But strong tides and unexpected gale force winds
0:33:50 > 0:33:56swept the two soldiers a mile from where they were supposed to land.
0:33:56 > 0:33:59There was a low search light. Every time the search light came down,
0:33:59 > 0:34:04came round, we had to flatten ourselves so it wouldn't pick us up.
0:34:04 > 0:34:09We gradually recovered the mile we'd lost.
0:34:09 > 0:34:15We loaded the samples into these containers, into each other's containers,
0:34:15 > 0:34:17and then we tried to swim out.
0:34:17 > 0:34:24And Bruce Ogden-Smith started yelling, so I had to swim slightly back to him.
0:34:24 > 0:34:30I said, "What's up?", and he was yelling, "Happy New Year!"
0:34:30 > 0:34:35I said, "Swim, you B, or we'll be back on the beach!"
0:34:38 > 0:34:42They were elated from the mission, but it was only the first.
0:34:42 > 0:34:47A fortnight later they risked it all again to collect more samples,
0:34:47 > 0:34:52which confirmed for the D-Day planners the safest places to land.
0:34:52 > 0:34:57The invasion was a huge gamble, but thanks to two Royal Engineers,
0:34:57 > 0:35:01the Allies knew they wouldn't be fighting the terrain when they hit the beach.
0:35:08 > 0:35:11The Germans had also been busy preparing for invasion.
0:35:12 > 0:35:17In 1942, Hitler commissioned around 15,000 concrete fortifications
0:35:17 > 0:35:24to guard the coast from Norway to Spain, the so-called Atlantic Wall.
0:35:24 > 0:35:28Ultimately, it offered little protection,
0:35:28 > 0:35:33but the Atlantic Wall remains the most visible reminder of Hitler's presence in this part of Europe.
0:35:35 > 0:35:39By contrast there's not so much to mark the Allies' impact on this coast,
0:35:39 > 0:35:43except here at Arromanches.
0:35:43 > 0:35:47These are the stranded pontoons of the Mulberry Harbour,
0:35:47 > 0:35:51the artificial port floated across the Channel by the Allies.
0:35:52 > 0:35:57Following D-Day, this is how they landed all the hardware needed
0:35:57 > 0:36:00to support the advance through France.
0:36:01 > 0:36:04Now the pieces are part of the landscape.
0:36:06 > 0:36:08On the beaches and dunes of coastal Normandy,
0:36:08 > 0:36:13the remnants of conflict are being colonised by nature.
0:36:13 > 0:36:18Miranda Krestovnikoff is looking for signs of life in the debris of war.
0:36:21 > 0:36:26They don't seem terribly hospitable, but these abandoned fortifications
0:36:26 > 0:36:30attract swarms of visitors each year - tiny, winged visitors.
0:36:33 > 0:36:36They're the favourite hang-out of what the locals here call
0:36:36 > 0:36:39chauve-souris - literally, bald mice.
0:36:39 > 0:36:40That's bats, to you and me.
0:36:44 > 0:36:51And this old munitions store has become a particularly popular party spot for the tiny creatures.
0:36:52 > 0:36:55So much so that naturalists from the group Mamalogique Normand
0:36:55 > 0:37:01are using the location to capture and record details of hundreds of bats.
0:37:01 > 0:37:07Working with the French scientists is Shirley Thompson from the UK Bat Conservation Trust.
0:37:07 > 0:37:11I have to say, if I was a bat it looks a good place to live, doesn't it?
0:37:11 > 0:37:13It certainly does, very out of the way.
0:37:13 > 0:37:16Why do they like it here? Why do they roost here?
0:37:16 > 0:37:17It's dark...
0:37:17 > 0:37:20it's cool because, of course, it goes right in,
0:37:20 > 0:37:22it's very stable and it's damp.
0:37:23 > 0:37:29It's such an attractive environment, that it's become the focus for a rarely seen event.
0:37:31 > 0:37:38Bats are notoriously shy and they hibernate during the winter, which makes them pretty difficult to see.
0:37:38 > 0:37:43But for a short time during the autumn they do something quite remarkable - they swarm.
0:37:44 > 0:37:50It's believed to be part of the mating behaviour and hundreds of bats can take part.
0:37:50 > 0:37:54For the French scientists, it's an opportunity to gather a huge amount
0:37:54 > 0:37:58of data on these secretive creatures to use in future conservation work.
0:38:01 > 0:38:06Now, it's going to be pretty tricky to spot bats approaching at night.
0:38:06 > 0:38:09Wow! That one nearly hit me, did you see?
0:38:09 > 0:38:13But Shirley has a secret weapon - a bat detector.
0:38:13 > 0:38:18We use a torch of light to go out in the dark, they use a torch of sound.
0:38:18 > 0:38:22They send out lots of little shouts, listen for the echoes that come back
0:38:22 > 0:38:26if those shouts hit anything, but they're very, very high shouts
0:38:26 > 0:38:30and a bat detector takes them in, makes the pitch lower,
0:38:30 > 0:38:32plays them out so that we can hear them.
0:38:32 > 0:38:34BAT DETECTOR CLICKS
0:38:34 > 0:38:37- Fantastic, because we can't see them at all, but we can...- No, no.
0:38:37 > 0:38:42So this is a really useful early warning device because even if we can't see them,
0:38:42 > 0:38:45- we can actually hear them. - That's right, yes.
0:38:45 > 0:38:47BAT DETECTOR CLICKS
0:38:50 > 0:38:57As we hear more and more bats arrive, it's possible for me to see them using an infrared camera.
0:38:59 > 0:39:05Fantastic, and with the echolocation they can detect the fact that there's a net there,
0:39:05 > 0:39:08and what's very interesting is that I've got quite a few flying in
0:39:08 > 0:39:11over the top of the arch, right over the top of the net.
0:39:13 > 0:39:16I think I've got two in the net,
0:39:16 > 0:39:18and the ones that are in the net seem to be...
0:39:18 > 0:39:21almost attracting other bats in.
0:39:21 > 0:39:24There's certainly quite a lot of activity now.
0:39:29 > 0:39:35Handling bats is highly specialised, and the naturalists have to be licensed to do it.
0:39:35 > 0:39:38But it's a chance to get up close to these remarkable animals.
0:39:41 > 0:39:46The Pipistrelle is native to Normandy as well as our own shores.
0:39:46 > 0:39:49I think if people actually got up close and personal with bats
0:39:49 > 0:39:52they wouldn't be scared of them, people are very scared of bats.
0:39:52 > 0:39:56And you see, another problem is that they always look as if they're cross
0:39:56 > 0:39:59with their mouths open, but that's because it's shouting.
0:39:59 > 0:40:03It's echolocating, it's looking at you with its ears as well as its eyes.
0:40:06 > 0:40:09Some bats will fly more than 30 miles to join a swarm,
0:40:09 > 0:40:13and the naturalists tonight have identified seven different species...
0:40:15 > 0:40:19..including the distinctive Natterer's bat.
0:40:19 > 0:40:21See its ears?
0:40:21 > 0:40:25It's got a little twist on the top,
0:40:25 > 0:40:29and these have such a fine wing membrane, can you see that?
0:40:29 > 0:40:32- Very fine.- Very fine membrane.
0:40:32 > 0:40:34It's beautiful. This is the best bit, isn't it?
0:40:34 > 0:40:39They've been processed, they're absolutely unharmed, unfazed by the whole thing.
0:40:39 > 0:40:41Five minutes later you're releasing them.
0:40:41 > 0:40:43They've gone to tell their friends.
0:40:43 > 0:40:46Let me just turn this on and see if we can hear him.
0:40:46 > 0:40:50Off he goes. Go on. Oh, magic!
0:40:59 > 0:41:02Out of the dark and into the light.
0:41:07 > 0:41:12The coast of France, like, Britain is ringed with lighthouses,
0:41:12 > 0:41:16their beams often crossing those of their counterparts across the Channel.
0:41:19 > 0:41:24The technology that made it possible came from Normandy,
0:41:24 > 0:41:27and it's lit up coasts around the world.
0:41:29 > 0:41:34At Gatteville, Dick is finding out how lighthouses were made...
0:41:34 > 0:41:36er, lighter!
0:41:38 > 0:41:44In the 1820s, the French government started to build lots of lighthouses,
0:41:44 > 0:41:47but it wasn't just to impress the neighbours.
0:41:48 > 0:41:51After years of war with Britain,
0:41:51 > 0:41:53the Channel was open for business again.
0:41:53 > 0:41:58It became an issue of national interest to keep shipping safe.
0:41:58 > 0:42:03The plan was to have every stretch of coast lit up by a lighthouse.
0:42:03 > 0:42:07It would have meant building hundreds of oil-burning beacons
0:42:07 > 0:42:10if it hadn't been for one local genius called Augustin Fresnel.
0:42:11 > 0:42:14He found a way of seriously stepping up their brightness
0:42:14 > 0:42:17by using a super efficient lens,
0:42:17 > 0:42:20the Fresnel lens.
0:42:20 > 0:42:27This one at Gatteville focuses the light so efficiently it can be seen 30 miles out to sea.
0:42:28 > 0:42:33It's a big torch, and all that's been done with a 1600 watt bulb.
0:42:33 > 0:42:37That's the equivalent of half the energy you use to boil a kettle.
0:42:37 > 0:42:41A mathematician and physicist, Fresnel came up with the idea
0:42:41 > 0:42:45of a lens made up of circular prisms of glass,
0:42:45 > 0:42:49but why didn't he just use a super-sized ordinary lens?
0:42:50 > 0:42:55Physicist Jonathan Hare has been looking into Fresnel's invention.
0:42:55 > 0:42:57Good to see you, mate. How you doing?
0:42:57 > 0:43:01OK, Jonathan, how can we don't use an ordinary shaped lens?
0:43:01 > 0:43:04The main problem is that they're so big and bulky.
0:43:04 > 0:43:06If you look at a standard lens,
0:43:06 > 0:43:10- and then scale this up... - It's going to get really fat and heavy, isn't it?
0:43:10 > 0:43:13It's going to weigh a ton, and be really thick,
0:43:13 > 0:43:16which will absorb a lot of the light.
0:43:16 > 0:43:17There's a better way of doing it.
0:43:17 > 0:43:21If you imagine this is a cross-section of a lens, what Fresnel did,
0:43:21 > 0:43:25which was very clever, he realised that it was this curved surface here
0:43:25 > 0:43:27which makes it act like a lens.
0:43:27 > 0:43:31So he thought, "I'll just take this curved part of the lens and cut that out."
0:43:31 > 0:43:35I can show you on here. You can see the bits that I've marked on here.
0:43:35 > 0:43:38So if we cut these out and bring them back, we get a very peculiar shape.
0:43:38 > 0:43:40- Did you make that yourself?- Yeah.
0:43:40 > 0:43:43- You've got your own Fresnel lens! - Yeah, out of plastic.
0:43:43 > 0:43:47I cut it up and polished it, and it is a peculiar looking shape, it's much lighter now.
0:43:47 > 0:43:50Oh, yeah, compare that. A significant difference there.
0:43:50 > 0:43:52But it is the same lens.
0:43:52 > 0:43:57We've taken take this bit here, and cut that off,
0:43:57 > 0:44:01and taken these bits here and put that on.
0:44:01 > 0:44:04We've taken these bits here and cut that off, and same again,
0:44:04 > 0:44:07same again there, and put them all on the one small lens.
0:44:07 > 0:44:11- All the important bits are there. - Yeah.- Does it work?- Yeah.
0:44:12 > 0:44:15OK, so here's a standard lens.
0:44:15 > 0:44:19The lens is basically focused to a point, and you can see
0:44:19 > 0:44:22that it bends the light, just like a lens.
0:44:22 > 0:44:25We know that works, cos it's the right shape.
0:44:25 > 0:44:27I'll show you how the Fresnel lens works.
0:44:27 > 0:44:32We hold that in place, and it should give exactly the same effect as the big one did.
0:44:32 > 0:44:34Exactly the same properties.
0:44:34 > 0:44:36It's got the same properties.
0:44:36 > 0:44:39- And it behaves the same way? - Exactly the same.
0:44:39 > 0:44:44So here's a commercial one, which is a much finer one, but basically it's made of rings.
0:44:44 > 0:44:46You can see the rings on it, can you see that?
0:44:46 > 0:44:49everybody thinks it's a magnifying glass for reading or
0:44:49 > 0:44:52looking at cars, but we know we can do something different.
0:44:52 > 0:44:57- If I hold that there, you can capture the rays of the sun. - That doesn't take very long.
0:44:57 > 0:45:03- It is actually a really efficient lens, but look it's as thick as a piece of card.- Brilliant.
0:45:03 > 0:45:07The focusing power of the lens means it has to be kept moving during
0:45:07 > 0:45:13the day to prevent the sun's rays burning out the bulb.
0:45:13 > 0:45:17- We can't go in, the mechanism floats on a bed of mercury.- And that's not nice.
0:45:17 > 0:45:20Mercury vapour is not on. But as you see, it must be really efficient.
0:45:20 > 0:45:24See that tiny nylon gear that's making it all move?
0:45:24 > 0:45:26- It's so perfectly balanced. - It's gorgeous.
0:45:26 > 0:45:31It raises the question, why aren't there more Fresnel lenses, because those are great?
0:45:31 > 0:45:34Well, the thing is, you wouldn't want them on a camera lens,
0:45:34 > 0:45:37because each of the rings of lenses distorts the image.
0:45:37 > 0:45:42They're absolutely great for shining out a beam of light, but if you try to use this in a camera...
0:45:42 > 0:45:47- It could be an interesting effect, the old Fresnel lens effect.- Maybe!
0:45:48 > 0:45:53This lightweight lens, invented in Normandy nearly 200 years ago,
0:45:53 > 0:45:56is still lighting the way for ships around the world.
0:46:05 > 0:46:11Coastal nations are united by the joy of being beside the sea.
0:46:12 > 0:46:18Some Brits, though, are so enamoured of the French and their coast, they've made their home here.
0:46:20 > 0:46:25For one English ex-pat, the wide open beaches of Normandy have an irresistible pull.
0:46:33 > 0:46:38My name's Sam Delorme, I moved over from England 11 years ago.
0:46:38 > 0:46:41I work with steeplechasers and cross-country horses,
0:46:41 > 0:46:44but today I've come down to the beach to see a good friend of mine,
0:46:44 > 0:46:47Franc de la Noe, train his trotters.
0:46:56 > 0:47:01The discipline is called harness racing, it's a very popular sport over here.
0:47:01 > 0:47:04In England, I think you're starting to get to know it,
0:47:04 > 0:47:06but over here it's very, very big,
0:47:06 > 0:47:08and he's very ready to go.
0:47:21 > 0:47:27He's gonna to be racing Sunday, so this is going to be one of his important work-outs for that race.
0:47:38 > 0:47:41To see a horse rolling after a work-out,
0:47:41 > 0:47:44it means he's calm, he's enjoyed himself.
0:47:44 > 0:47:49To get them away from the routine, they're like us, it's good for them.
0:47:49 > 0:47:52So if they're feeling good, it shows in their racing afterwards.
0:48:00 > 0:48:06At this point in our journey, the British Isles are once again within touching distance of France.
0:48:08 > 0:48:13At their closest the Channel Islands are only ten miles from the Normandy coast,
0:48:13 > 0:48:18but for 800 years they've been loyal to the Crown of England...
0:48:18 > 0:48:20well, most of them!
0:48:22 > 0:48:27Nick is on a voyage to the French Channel Islands.
0:48:29 > 0:48:32It's not often you get a chance to visit a land that magically
0:48:32 > 0:48:38emerges from the waves, but that's what Jersey skipper Chris Fairburn
0:48:38 > 0:48:42has promised I'll see at the Iles Chausey, the French-owned Channel Islands.
0:48:43 > 0:48:47He's made the trip many times, but before we arrive,
0:48:47 > 0:48:50there's a small ceremony to perform.
0:48:52 > 0:48:55We don't have to hum the Marseillaise if you don't want to.
0:48:55 > 0:48:59Would it be a problem for the French if you didn't raise the tricolour?
0:48:59 > 0:49:04They have been known to fine people if they don't have the courtesy flag flying.
0:49:04 > 0:49:06You mean, there's real tension on...
0:49:06 > 0:49:10No, that's just customs men in France finding something to do in a day!
0:49:10 > 0:49:15Or maybe they're just keen to remind foreign sailors that
0:49:15 > 0:49:19the Chausey Islands are part of France, albeit a very small part.
0:49:22 > 0:49:29Compared with the likes of Jersey and Guernsey, the Iles Chausey are tiny.
0:49:29 > 0:49:34But as you get closer, they begin to reveal their secrets.
0:49:43 > 0:49:45This is a nautical obstacle course.
0:49:45 > 0:49:49One wrong turn and you run onto the rocks.
0:49:49 > 0:49:52There are islands absolutely everywhere.
0:49:54 > 0:49:58The largest is also the only one that's inhabited.
0:49:58 > 0:50:05With a native population of about 30, this is the audaciously named Grande Isle, The Big Island.
0:50:10 > 0:50:13It's only a mile and a half long, there are no Tarmac roads,
0:50:13 > 0:50:17there are no cars or buses and even bikes are banned. Suits me.
0:50:30 > 0:50:34I've been told island life revolves around an old fort.
0:50:34 > 0:50:41It was built by Napoleon III to defend against a British invasion which never came.
0:50:43 > 0:50:47Chausey historian Gilbert Hurel has agreed to show me around.
0:50:48 > 0:50:52So, Napoleon built this enormous fort to keep out the English,
0:50:52 > 0:50:56but why didn't the English get their hands on the Chausey Islands in the first place?
0:50:56 > 0:50:58There was no strategic interest.
0:50:58 > 0:51:04It was too small, no shelter for boats, and too close to the French mainland.
0:51:04 > 0:51:06This fort was built for nothing,
0:51:06 > 0:51:11never been used for military reasons. Now fishermen live in it.
0:51:11 > 0:51:17It's quite a sight because you come in from the outside expecting a kind of sense of
0:51:17 > 0:51:23military order, and what we have is the most picturesque jumble of fishing paraphernalia everywhere.
0:51:23 > 0:51:25It's a wonderful sight.
0:51:25 > 0:51:29It's now home to most of the islanders,
0:51:29 > 0:51:33out at their day jobs fishing for lobster and shrimp.
0:51:33 > 0:51:37Gilbert has offered to help me catch up with one of them.
0:51:44 > 0:51:48I've noticed you never look at a map, you don't have any charts...
0:51:48 > 0:51:50No, but I know the place by heart.
0:51:51 > 0:51:53Here is Freddo coming.
0:51:53 > 0:51:56Oh, I see, a little dory like yours.
0:51:56 > 0:52:00Frederic LaGronde - Freddo, as everybody knows him -
0:52:00 > 0:52:04has been living and fishing on the island for almost 50 years.
0:52:07 > 0:52:13- So he's been fishing shrimps, which is a local speciality...- Good size.
0:52:13 > 0:52:15Freddo, is this a good catch?
0:52:15 > 0:52:18THEY SPEAK FRENCH
0:52:18 > 0:52:21"It's not bad at all."
0:52:21 > 0:52:24And when he says it's not bad, it means it's rather good.
0:52:24 > 0:52:26He is Norman, you know.
0:52:30 > 0:52:35It's a very Norman thing, Gilbert tells me, not to be overly enthusiastic,
0:52:35 > 0:52:39and it seems even the islands share this modesty,
0:52:39 > 0:52:41until the tide goes out.
0:52:52 > 0:52:57This part of France has one of the largest tidal ranges in the world.
0:52:57 > 0:53:02The water drops a staggering 14 metres to reveal miles of sandbanks.
0:53:06 > 0:53:09This is absolutely incredible, I had no idea
0:53:09 > 0:53:13that there was such a huge landmass lurking beneath the waves.
0:53:13 > 0:53:15That's where the heart of Chausey beats.
0:53:15 > 0:53:18You'd never think, as you come across the top of this bit of the ocean
0:53:18 > 0:53:23in a boat, that there's a secret world down here on the seabed
0:53:23 > 0:53:27- that you can walk on at low tide. - You can walk on the seabed, really.
0:53:28 > 0:53:34When the tide goes out, the Chausey Islands are an incredible 60 times bigger.
0:53:38 > 0:53:40And they still have one more surprise...
0:53:42 > 0:53:44..a deserted quarry.
0:53:50 > 0:53:53Here's a huge block that has been split,
0:53:54 > 0:53:56but they've just abandoned the stone.
0:53:57 > 0:54:05Islanders quarried granite here for generations, when the easiest way to transport the heavy stone was by sea.
0:54:07 > 0:54:13And it's the route those original quarry ships must have followed that leads us away from Chausey,
0:54:13 > 0:54:20because their precious stone cargo helped to build one of France's most distinctive landmarks...
0:54:22 > 0:54:26..the monastery at Mont-St-Michel.
0:54:31 > 0:54:36Benedictine monks started building here in the 8th Century.
0:54:38 > 0:54:40The mount itself was created by the tides,
0:54:40 > 0:54:45endlessly striping away the soft earth, leaving hard granite behind,
0:54:45 > 0:54:47and looking, for all the world,
0:54:47 > 0:54:50as if it was placed there by an unseen hand.
0:54:53 > 0:54:58The same tides that submerged the Chausey Islands daily flood through here.
0:54:58 > 0:55:02It's not surprising that the monks thought that something supernatural was going on.
0:55:05 > 0:55:10But I've more earthly concerns on my mind, like what I'm having for my tea.
0:55:11 > 0:55:17I'm on my way out to a farm, but it's a farm unlike any other.
0:55:17 > 0:55:21For a start, you can only get to it in amphibious craft.
0:55:25 > 0:55:31Here they grow a famous French foodstuff - moules - mussels.
0:55:36 > 0:55:42These wooden stakes, called bouchots, are seeded with coiled ropes of young mussels,
0:55:42 > 0:55:44and then they're simply left out here to grow.
0:55:44 > 0:55:49Mussels wouldn't live long exposed to the air like this,
0:55:49 > 0:55:54but the farmers here have learnt to exploit the huge rise and fall of the tide.
0:55:54 > 0:55:57When the sea is out they're easy to pick off.
0:55:57 > 0:56:01In a few hours they'll all be submerged, so they have to work quickly.
0:56:03 > 0:56:05This is just astonishing.
0:56:05 > 0:56:09For some reason, I'd imagined that French mussel harvesting would
0:56:09 > 0:56:13involved women with wicker baskets wading into the sea with rakes,
0:56:13 > 0:56:16but it's anything but.
0:56:16 > 0:56:21It's this hydraulic hand that just goes down over the wooden stake
0:56:21 > 0:56:25and so easily scoops up the rope of mussels.
0:56:25 > 0:56:29It's brilliant, but it's not quite as romantic as I'd hoped.
0:56:29 > 0:56:34Alain Chevalier's family have been growing mussels for generations.
0:56:40 > 0:56:42OK, give me one.
0:56:48 > 0:56:50You watching?
0:56:55 > 0:56:59There's a reason why they cook these things, you know?
0:57:04 > 0:57:08Every stretch of coast is unique, like a personality.
0:57:08 > 0:57:13But like people, coastlines can have a great deal in common.
0:57:13 > 0:57:19In some ways, it feels as if we and the French share the same shore.
0:57:27 > 0:57:30And here, at the end of our journey, is one more thing we share with
0:57:30 > 0:57:35the French - the monks who built this also did a spot of construction work
0:57:35 > 0:57:36on the English coast.
0:57:38 > 0:57:43And this is where they built a church - St Michael's Mount, on the Cornish coast.
0:57:45 > 0:57:49Next time, we travel from the granite of Cornwall
0:57:49 > 0:57:52to the sand of South Wales.
0:57:52 > 0:57:53There's a sword...
0:57:53 > 0:57:57Wow! Look at that.
0:57:59 > 0:58:00..seals...
0:58:03 > 0:58:05..and scares.
0:58:05 > 0:58:06I'm clinging onto everything.
0:58:08 > 0:58:12If you want to know more about our coast, the Open University
0:58:12 > 0:58:16has produced a booklet with ideas and information to inspire you.
0:58:16 > 0:58:20For a free copy or to find out more about Open University programmes
0:58:20 > 0:58:21on the BBC...
0:58:36 > 0:58:39Subtitles by Red Bee Media Ltd
0:58:39 > 0:58:43E-mail subtitling@bbc.co.uk