Original subtitles

Scotland is a breathtakingly beautiful country.

And no more so from the air.

It boasts one of the most photogenic landscapes in the world.

No wonder it's one of the most photographed.

Ever since the invention of flight,

aerial photographers have taken to the skies and taken thousands of

photographs. They are a record of how our countryside, our cities,

even our way of life are constantly shifting and changing.

These photographs are an extraordinary window into our past.

They can take us back in time and show us how our great cities have

dramatically changed with the ebb and flow of history...

..while whole communities have vanished in the name of progress.

They can reveal treasures from the past...

..without even lifting a spade.

And they can uncover secrets buried right beneath our feet.

Did you realise that where you are standing was once a massive Roman

military camp? Never imagined that.

From Roman camps,

to lost ornamental gardens,

to a field where the very concept of time emerged.

Without that photograph, we wouldn't be here today, no.

This is the fascinating and untold story

of those pioneering photographic

detectives and the extraordinary mysteries they have uncovered.

This is the story of Scotland From The Sky.

INDISTINCT FORECAST ON RADIO

The skies are clear and the wind is light.

Perfect conditions for today's task.

I've come to Cumbernauld Airport for a flight with a difference.

What are you shooting with today, Bob?

Bob Adam is a photographer with Scotland's National Collection of

Aerial Photography. And this little Cessna is the team's workhorse.

Tight fit in here.

It's not the most comfortable flight I've ever taken,

but it beats most people's commute to work.

Spring, summer, autumn or winter,

the survey team from the National Collection

take to Scotland's skies.

SHUTTER CLICKS They are photographing change...

..fields...

..roads...

..cities...

..how we are constantly transforming our landscape.

SHUTTER CLICKS

The National Collection has been photographing us from the skies for

over 40 years and if you know what to look for,

you'd be astonished just how far back in time you can see.

The annual survey started in the scorching summer of '76 -

an extraordinary year to begin.

Britain was baking in a long, stifling heatwave

and suffering one of the most severe droughts ever recorded.

But what was torture for office workers

proved perfect for aerial photographers.

Under the relentless sun,

the landscape became like a litmus paper for the past.

As the dry spell took hold, crops turned pale and parched.

But the crops that grew above ancient earthworks remained healthy

and dark as the roots found moisture deep underground.

Like ghostly outlines,

crop marks of prehistoric structures began to emerge from fields

across the country.

On one particularly scorching day,

an aerial archaeologist was flying above this field near Crathes Castle

just to the east of Banchory in Aberdeenshire -

this is what he was looking for.

The crop mark of an ancient great hall, built nearly 6,000 years ago.

But later, he noticed this.

A series of dark, regularly spaced dots running in a straight line.

So what were these strange, mysterious circles?

I've come to Crathes Castle to take a look for myself.

You can barely spot them in the photograph, but here on the ground,

I've no chance.

There is nothing to be seen at all.

Although photographers came back year after year,

the crop marks were never seen again.

But the archaeologists had their glimpse -

they knew where to look and when they came to excavate the site

they found something that defied explanation.

It would completely overturn our understanding of the past.

The chief archaeologist, Shannon Fraser,

has joined me at the site to tell me what she discovered.

They were a whole long line of quite big pits,

really quite deep and quite broad,

running along the landscape in a more or less straight line,

with kind of a kink at one end.

Different sizes, different shapes, but all really quite, quite big.

And how old were they? Well, they were very,

very much older than any of us possibly expected.

It was a real sit-down-in-your-seat moment when we got the radiocarbon

dates back, because there were a range of them starting, really,

about 10,000 years ago and running through the next thousand years or

so, which put that right in, really,

the beginning of the period when people are coming back into Scotland

after the retreat of the ice.

So that was really surprising and exciting.

And what do you think these pits were for?

Well, looking at the dating evidence and the archaeological evidence,

what we could see was happening was that people over an incredibly long

period of time were coming and digging these big pits.

In most of them they were then placing the ashes of fires,

very carefully in the bottom, and then they were moving around them

and the soil starts to just come back in and then nothing,

then they go away and vegetation starts to grow and then they come

back and they do similar things and this process is going on,

for, literally, 1,500 years. So, thinking about that,

we came to the conclusion that what's probably happening here is a

ceremonial site that people are coming to, meeting,

reaffirming bonds of friendship, that sort of thing, probably

tying the communities into the land and belonging and well-being,

at those specific times of year - that's what we think may be

happening. And you never would have found it, if it had not been for

this photograph. If it had not been for that photograph,

that was the only time that the site ever showed up, yeah,

so without that photograph, we wouldn't be here today, no.

But the story doesn't stop there.

The mystery of the Warren Field Pits has caught the imagination of many

academics and a number of intriguing theories have been proposed.

One team has come up with a tantalising possibility.

That here, what is now an empty field in Aberdeenshire,

the very concept of time was invented.

News of the excavation reached Professor Vince Gaffney,

who, at the time, was working at Stonehenge.

When he discovered that the central pit lined up with sunrise on the

Midwinter Solstice, he put together a team to find out more.

We realised that it was pointing towards the slope of the pass and,

10,000 years ago, this pass would have had the sun rising through it

on the Midwinter Solstice,

so it suggested straightaway that we were looking at a monument with

some sort of astronomic alignment and this is very, very, very rare,

for hunter-gatherers to have

that sort of concern with astronomic events.

While the central pit lined up with the midwinter sun,

what did the other 11 do?

Vince had a theory.

The pits themselves may be associated with a reflection of the

phases of the moon, going through from waxing, gibbous,

full and into the waning cycle.

Vince believes these 12 pits might symbolise the 12 lunar months.

While their varying sizes - from small to large, and back to small -

represent the waxing and waning of the moon.

They were inscribing their notion of the passage of the moon in the land,

in order to have some form of tracking time.

There is nothing comparable in north-west Europe that we can see at

the moment, so in some senses,

a concept of time emerged here.

Vince's theory remains open to fierce debate.

But what we do know is that, for 10,000 years,

this area has always been a magnet for people.

And for the last 700, it has been home to the Burnett family.

Every summer, hundreds of Burnett descendants from around the world

return to Scotland to celebrate the sense of belonging that all

of them share.

Events like these clan gatherings,

with all their celebration and sentimentality,

are still just about a simple communion with place.

They are about understanding who you are and where you're from and they

are about why, perhaps without knowing,

you always feel compelled to keep coming back.

The accidental discovery of the mysterious pits at Crathes Castle

showed us just how much we can learn about our ancient past from the air.

Thanks to that drought of 1976 and a camera poking out of an aeroplane

window, we were briefly, fleetingly, able to see further back

in time that we had ever seen before.

So much more of ancient Scotland was just waiting to be uncovered.

The precious photographs of the Crathes Castle pits is stored here

in the vaults of Historic Environment Scotland in Edinburgh.

It's where the National Collection of Aerial Photography is held and

it's where I work, researching and uncovering its secrets.

Millions of aerial images can be found here and every one a potential

clue to our rich history.

It seems extraordinary, looking back now, but until recently,

Scotland's past was largely neglected.

In the late 19th century,

there were only 21 legally protected ancient sites and monuments in

Scotland. It was a tiny list, made up of a few stone circles,

some carved stones,

a handful of ruined towers and a couple of prehistoric tombs.

There wasn't even a castle.

That tiny list has grown to nearly 10,000 protected sites today.

And that's thanks to the father of aerial archaeology who kick-started

the quest to uncover Scotland's lost history.

Osbert Guy Stanhope Crawford was an observer for the Royal Flying Corps

during the First World War.

As the battles raged in the trenches below,

he saw through the bloody present to the ancient past,

saw how the battlefields beneath had once been shaped by prehistoric

farmers and Roman settlements.

In 1920, Crawford became

the Ordnance Survey's first-ever archaeologist.

Here he is, dressed in the suit and waistcoat, trousers rolled up,

sporting his old flying helmet and furry mittens.

His only mode of transport, his trusty bike.

It's a strong look.

Throughout the 1930s, he pedalled around Scotland,

bags hanging from the handlebars, maps wrapped around the crossbar

and I suspect he had shorter legs than me!

He worked and lived like this, riding from site to site,

sometimes on the road for a month or more at a time.

He brought the same urgency to his job as he had to his wartime

observation work. He saw it as equally important.

He once boasted he cycled 72 miles - from Stonehaven to Blairgowrie -

in a single day.

But Crawford's bike and his short legs had their limitations.

He wanted to explore more.

To see more.

And Crawford knew the only way to do this was from the air.

In the summer of 1939,

he requested permission to conduct an aerial survey.

His bosses refused and suggested he take a taxi instead.

But Crawford was stubborn and paid for the aeroplane himself.

The owner of this beautiful vintage Tiger Moth is William McCaness.

And he has offered to fly part

of the route that Crawford flew in 1939.

So, overalls will stop you from snagging anything and then this is a

nice warm urban jacket,

which right now will make you feel really hot and warm,

but once you're in the air, you will be really grateful for it.

When does this jacket date from?

World War II.

It is a genuine article.

Now, the helmet or the cloth helmet here,

you just sort of duck your head forward...

That's it.

And it does restrict your view a bit, so if you want to,

you can always then just put it back on top of your head. Perfect.

Shall we go? Yes.

This isn't really for nervous flyers.

There's not even a door.

At least there is a seat belt and I get to sit in the front.

The starting method looks... interesting.

But I've got every confidence in William.

At least, I think I do.

And if you're thinking this looks precarious, it feels it.

OK. Here we go.

There's no turning back now.

Well, we're up now, and do you know what?

I'm actually starting to enjoy myself.

In fact, this is amazing.

The original trip above the Scottish lowlands cost Crawford £27.

That is around £1,000 in today's money.

But it was worth every penny.

Crawford became the Sherlock Holmes of the skies.

It felt like the future.

Technology revealing how the living shared the land with the dead.

How ghosts are, in a sense, all around us, all of the time.

But of all the peoples that haunted this landscape,

it was the Romans that fascinated Crawford the most.

Crawford's route took him over the faint remains of one of the great

frontiers of the world.

The Antonine Wall was built in the mid-2nd century AD.

Named after the Emperor Antoninus Pius,

it snaked between the Clyde and Forth estuaries.

North of the wall, the territories of the barbarous Caledonians began.

This section just west of Falkirk is a fractured line of humps and

ditches, running around housing estates,

through back gardens and under power lines.

Back in the 1930s, historians thought that Highland Scotland

had remained mostly unconquered,

that the Romans hardly set foot beyond the central belt.

The only discoveries beyond it had been a handful of impressive

outposts like Ardoch Fort, near Braco,

built to secure the lowland conquest.

But during the summer of 1939, as Crawford flew north into Perthshire,

he discovered dramatic new evidence of Roman sites, including roads,

forts and camps.

A discovery that would rewrite

our understanding of the Romans in Scotland.

How many more camps and forts lay hidden?

And how far north did the Romans actually go?

These questions would have to wait.

One month later, Britain declared war on Germany.

In 1946, Crawford retired.

Into the driving seat stepped this man.

John Kenneth Sinclair St Joseph spent his war as a spy in the sky,

interpreting aerial images from military intelligence.

St Joseph proved to be a genius at detecting enemy movements from

photographs - skills he would use after the war to study great

military campaigns, not of the present, but of the past.

He was obsessed by the unanswered questions about Roman Scotland.

St Joseph doggedly set out on the trail of the Imperial Army,

chasing the crop marks of military camps

further and further northwards.

What he discovered astounded him.

His aerial photographs showed up lines and geometric shapes in field

after field, like giant footprints of a brutal ancient war machine

that scarred the landscape - Roman marching camps.

St Joseph discovered a staggering 130 of them.

He had revealed the scale of the Roman invasion and proved that the

Roman campaign went further north of the Antonine Wall than anyone had

previously thought.

These were temporary marching camps for an army of thousands of soldiers

on the move...

..running from Perthshire through Angus to Aberdeenshire and Moray,

strung out in a line,

the camps appeared like a giant signpost in the landscape.

St Joseph knew he was onto something.

There was a fabled story of a titanic Roman victory over

the Caledonian tribes. The Battle of Mons Graupius.

It is one of the great mysteries of history,

because no-one knew where the battle had taken place.

Could this line of camps lead St Joseph to the biggest prize of all -

the fabled battlefield itself?

One camp in particular caught St Joseph's eye.

It was hard to miss.

The camp was one of the biggest ever found in Britain.

It lies under the small, quiet town of Kintore,

on the main road between Aberdeen and Inverness.

St Joseph believed the camp might hold the key to Mons Graupius and

was the base of the Roman legions that fought the epic battle.

Sprawling housing estates now cover the site, and standing on the

southern entrance gate is Kintore School.

It's hard to believe that where I'm standing was

once a Roman military camp.

When St Joseph photographed this site in 1949,

his pictures showed the sheer enormous scale of it.

It was a sort of Caledonian Camp Bastian.

Temporary home to thousands of men and the front line in a war against

marauding Picts.

Hi, Murray. Yeah, hi, how are you doing? Good to see you.

Lovely. What a lovely day. Yeah.

Dr Murray Cook led the archaeological dig of the camp

back in 2002.

So, Murray, you have brought a map with you which shows how the

enormous scale of the Roman camp

overlapped onto the modern town of Kintore.

Yeah. The camp, which is a fairly standard one,

is 44 hectares in size.

We are standing just here.

There is an entrance here just under the motorway.

There is an unexcavated entrance here.

The whole camp is orientated north, because that is the attack.

It's massive, it's 44 hectares.

We are on a football pitch,

imagine at least 60 of these and you begin to come close to the scale.

60 times this area, completely taken over by marching camps, by soldiers,

by equipment, by horses and - don't forget -

a big area in the middle for slaves.

This is invasion.

This is making Kintore, Scotland, part of the Empire,

ruled from Rome.

They are here to go as far, probably as Elgin, as far as the Moray Firth,

to basically conquer, to secure, to form treaties with the local

tribes and to make sure that they bow the knee to Rome.

Although large, the layout of the camp was fairly standardised.

On the perimeter, under Kintore school, were dug the outer ditches.

On top of the earthen ramparts, a palisade was constructed

by binding together wooden stakes that were carried by each legionary.

There were three entrance gates and, just by the side of what is now the

A96, a large watchtower.

The area within the camp was subdivided into streets,

along which soldiers pitched their tents and dug latrines.

And in the centre of the camp, an area where slaves were held,

occupied today by the houses on Henderson Drive.

When Murray Cook excavated Kintore,

the team made some surprising discoveries.

When we dug here, we found more bread ovens than had ever been found

in Roman Britain. These ovens, they are all different sizes,

different techniques, they reflect their traditions,

the ethnicity of this army that's coming on foot,

step-by-step-by-step, day after day, from the south, to conquest.

So all these traditions, all these international voices, different

skin hues, different religions, all descending on this location.

Different pizza toppings?

Yeah! Syrian, Iranian, Italian, you name it, they were here.

No Hawaiian, though. No Hawaiian.

And could these ovens have been the ones that fed the men who marched to

Mons Graupius?

Well, I would say, the people that ate that bread fought at

Mons Graupius, but I think Mons Graupius is that way.

Murray thinks St Joseph got it wrong,

and that Mons Graupius lies 100 miles south.

That is because a Roman source

described a Fort near Dunning in Perthshire

called Victoria, in honour of the decisive Roman victory.

We may never know the actual location of Mons Graupius,

but it is extraordinary to think that the vast camp that once stood

here was home to the Roman legions who fought this legendary battle.

I'm curious to find out if the local people of Kintore are aware

of their Roman roots.

Do you realise that the village of Kintore sits on the site of a

2000-year-old Roman camp?

No. No.

I would never have known that.

Beneath your feet were a huge collection of pizza ovens.

Wow!

Do you realise that where you have just been riding your bike across

was once a massive Roman military camp? No.

You can't blame them for not knowing.

When the Romans retreated south in the second half of the second

century, they took anything of value with them,

leaving only their bread ovens.

The people of Kintore would have to wait a long,

long time before pizza was back on the menu.

About 1,800 years, to be exact.

With his aerial photographs,

Kenneth St Joseph had revealed hundreds of lost ancient structures

buried beneath the landscape.

But in the early 1950s,

these sites came very close to being bulldozed from history.

After the experience of wartime rationing,

the government became obsessed with achieving self-sufficiency

and Scotland looked like the place to do it.

Huge areas of the country were to go under the plough.

Massive forests were to be planted.

And valleys flooded for hydroelectric power.

The pace and scale of change spurred one man into action.

Kenneth Steer had returned from the war to his post as archaeologist for

Scotland's National Collection.

He was convinced that there were thousands of monuments,

even tens of thousands that were still unknown,

but how was this poorly funded team of four men and one woman possibly

going to save them?

Steer knew he had to persuade the government that these ancient

monuments were worth preserving and he knew just where to start looking.

The plane takes off on a mission that is part of a vast programme of

photomapping. This plane, the aerial surveillance task is to

help record the changed face of Britain.

Between 1944 and 1950, the RAF had carried out an aerial

photographic survey of all of Britain.

Called Operation Review, it saw some 500 flights above Scotland,

taking nearly 300,000 pictures.

The photographs are now stored here,

at Scotland's National Collection of Aerial Photography.

What is remarkable about these images is that they are photographed

in 3D, to help map-makers identify contours in the land.

But to see them in 3D, you need a stereoscopic viewer.

This is a stereoscope.

It is a device that is used to turn 2D into 3D.

What you need are two images of the same thing,

but taken from slightly different angles.

I look through the stereoscope viewer and I try to make the

features on the images overlap.

It's weird at first.

Then all of a sudden, two becomes one.

Your brain is tricked into seeing three dimensions.

By viewing the landscape in 3D from above,

Steer's team spotted hundreds of possible undiscovered ancient sites.

The sheer volume of finds sparked Steer into announcing an emergency

survey, a rapid and systematic attempt to map and measure

Scotland's threatened heritage.

Sites only seen in photographs would now have to be investigated

in person. Driving an ex-army jeep,

the team headed out into the Scottish countryside.

By the summer of 1950, the emergency survey was well under way.

Sites were visited in small teams and work that would normally take

days was undertaken in hours.

Think speed-dating for ancient monuments.

But sometimes they were already too late.

An ancient fort at Dalks Law in Lammermuir Hills,

photographed in 1928, was gone.

Completely ploughed out by farming.

Elsewhere, archaeology was quite literally in the firing line.

Chambered cairns made top targets for artillery practice.

It was a race against time, but in the remoter places, on lonely

hilltops, earmarked by the government as marginal land,

sites had been spared the plough or the bulldozer.

This is one of them.

A great Iron Age hill fort near Duns, built 3,000 years ago.

I've come here with archaeologists George Geddis and Adam Welfare to

recreate the survey, using the very same equipment from the 1950s.

Well, the first part of that is just a sheet of cartridge paper,

which is what they would have used at the time.

Not very weatherproof.

Then the next crucial thing we need is a little pin.

Everything we measure on the drawing

will be done in relation to that pin.

So now in order to actually make our drawing,

we use two items of equipment -

the first one is this thing called an alidade.

This is from about 1950 and the second thing is our tape.

That's it.

Tape measures, pencils, rulers, rods

were all used to measure the ancient structure.

It might not look much,

but sites like this are often the only physical evidence of our

prehistoric past.

Old stones, humps and bumps in the landscape

were the crumbling clues to who we once were.

Kenneth Steer filled his notebooks with handwritten

detailed descriptions of what the team found.

And they produced meticulously measured drawings like this one.

You can see the detail here.

The wonderful sense you get of both accuracy and artistry.

These were fast-paced, functional drawings - but to me, anyway,

they retain a unique sense of skill and beauty.

They're a tiny bridge between the present and the past -

a kind of conversation with our ancestors.

But while the drawings were incredibly detailed,

they are no substitute for viewing this place from above.

It's only when you look down at the scale of this earthwork and imagine

houses that once stood here, the tendrils of wood smoke

drifting into the air and the high timber walls and the earthen

ramparts that you realise...

..forts like these were all about demonstrating power,

about holding dominion over the surrounding countryside.

These hill forts were, in a sense,

sowing the seeds of their own destruction.

They were the ones that first stamped the land with ownership,

overseeing the parcelling up of people, fields, livestock...

They began the creation of the modern world,

a world where everywhere is owned by someone.

Far from the past being an empty and mysterious place,

the emergency survey began to reveal a landscape bustling with people,

living, working and defending their way of life.

Without the work of Steer and his team,

the post-war drive for self-sufficiency would have erased

the lives and homes of our ancient ancestors from history.

60 years on,

the National Collection of Aerial Photography uses a plane,

rather than an ex-army jeep.

The tools and transport have changed,

but the job remains the same.

I am heading out to sea with the aerial survey team.

They are on the lookout for the indelible marks left on Scotland's

coasts by our ancestors.

Since the National Collection started flying, thousands

of new coastal archaeological sites have been discovered.

The reason there are so many is because in the Scotland of old,

it wasn't roads that linked communities,

it was the wide-open superhighway of the sea.

Overshadowed by the brooding and dramatic Cuillin Mountains,

the Southern tip of the Isle of Skye is incredibly beautiful.

It's one of my favourite spots.

This is the Rubha an Dunain peninsula, with its tiny loch.

To most visitors, it looks remote and lonely.

Home only to sea birds and seals.

But from above, it's revealed a landscape with an intriguing past.

Tumbledown walls...

..ancient dwellings...

..and up on the outcrop, a hillfort.

All clues to a time when the peninsula

was a vibrant hub of human activity.

So who were the people who lived here and what brought them to this

remote place?

Around 20 years ago,

Rubha an Dunain's mysterious past began to be uncovered when an

extraordinary piece of evidence came to light.

OK, I know it doesn't look much, but to people who build boats,

this is a crossbeam.

And it connects the hull to the floor timbers.

What makes this one so special is that it once belonged to a nearly

1,000-year-old forward seagoing boat.

It was discovered in shallow waters

in a little loch at the Rubha an Dunain Peninsula.

What got archaeologists excited

were the intriguing questions this bit of wood posed.

Who built it, and why was a seagoing boat abandoned

in a landlocked shallow loch?

The best way to find out was to take a trip there myself.

My guide is maritime archaeologist Dr Colin Martin.

Following the discovery of the wooden crossbeam,

he brought a team of experts to carry out a survey of the peninsula.

So, Colin, roughly where was the fragment of the boat discovered?

Well, it was found right over on the other side of the loch there,

by a local man.

The timber was actually sticking out and he raised it.

How old was it? Well, some time later it was radiocarbon

tested and it came to around 1100 AD,

smack in the middle of the Norse period.

So nearly a thousand years old. Nearly a thousand years old, yes.

Let's go see more. Let's do that.

For centuries,

tales from local folklore told how the peninsula was once home to the

Vikings. These tales had been dismissed by historians,

but when the team arrived,

they were excited to find some intriguing man-made features.

The most obvious feature is this structure,

which links the approach to the dun and the fort on the headland and the

loch that we see out here.

This obviously was our first focus of interest.

You later found that the view from above was instrumental to your

interpretation of this site. Absolutely it was.

We used a drone to get much more detailed information and accurate

surveys of the very complex rubble

of stones that are lying all over the place,

which from ground level appear really beyond interpretation.

While times and technology have changed,

the job of surveying is the same.

The drone took hundreds of pictures and then a computer worked out the

measurements, right down to the size of individual stones.

The pictures were processed to create a top-down,

vertical image of the entire site.

What was revealed exceeded everyone's expectations.

An engineering marvel that had been lost for centuries.

A Viking dockyard.

Colin, how did it feel to work on a site like this?

It was very exciting,

because as we gradually pieced together the information -

actually the hard evidence of what was there -

we began to see how this whole place functioned and we began to get a

feel for the people who were part of it.

From above, the layout of the dockyard became clear.

The natural stream that ran from the loch to the sea was widened and

stone walls built to form a canal.

At the harbour entrance,

two noosts - or dry docks - were built where boats were pulled up

and repaired.

Servicing the dry docks were some small buildings,

probably storehouses, or living quarters.

Halfway along the canal, a sluice gate - used to control

the water levels between the loch and the sea.

Then at the end of the canal,

there were two quays and a large turf-covered building.

For centuries, the Vikings who built the dockyard dominated this region,

controlled the local seaways, lords of all they surveyed.

It's the sort of place that brings the past really to life, isn't it?

Absolutely. And could you imagine what it must have been like for them

to live and work here?

I think it would have been a hard life.

A life that demanded a lot of skill in various ways and also

the knowledge that if you didn't apply your skill properly,

you were probably going to be dead.

It was much more extreme and the prices for failure were much greater

and I think that probably had an effect on the character of the

people. Would you have liked to have worked here?

No. I'm too soft and modern!

The Viking dockyard has long since been abandoned,

and nature has reclaimed it.

Rather than take the motor launch we arrived in,

Colin and I are taking a more authentic form of transport home.

A wooden rowing boat,

similar to the one recovered from the loch 1,000 years ago.

I suspect the Viking workers who once laboured here would approve.

Every year since 1976,

Scotland's National Collection of Aerial Photography has been flying

all over the country in search of our history.

And as the years passed, much more has been discovered than

the activities of Roman legions or Viking raiders.

Entirely new aspects of Scotland's history began to appear in the most

unexpected of places.

Places such as Castle Kennedy in Dumfries & Galloway.

A romantic crumbling ruin today, but once home to Sir John Dalrymple,

the second Earl of Stair, a military man with a passion for gardening.

In 1984, a National Collection archaeologist

was flying above the picturesque ruin of the former Earl's home.

And in the flat empty lawns in front of the old castle,

she photographed a series of puzzling patterns and lines,

like an old plan etched into the modern landscape.

Pathways, steps and a mysterious circular feature set at one end.

The archaeologist was Marilyn Brown and the discovery would come to

dominate her work for the next 30 years.

It was remarkably dry in 1984 in Galloway and I had been carrying out

aerial survey, looking for the remains of Neolithic, Bronze Age,

Roman, Iron Age and later settlement in this area.

But coming across Castle Kennedy I saw, to my surprise...

..lines, terraces, possibly the remains of staircases.

So, in effect, this was a ghost garden

emerging out of the landscape. Yes, it was.

What Marilyn Brown had photographed were the fading skeletal bones of a

beautiful ornamental garden,

typical of the Stewart period.

There is very little evidence of what it used to look like.

But there are living clues, if you know what to look for.

It's a herb, called a greater celandine.

And what was so special about it was that its seed is over 300 years old.

It was buried deep and dug up by Castle Kennedy's head gardener.

It is related - if plants can be related -

to the old plants that grew here over three centuries ago.

A living ghost.

Another clue was left by General William Roy, who made maps of

Scotland in the aftermath of the second Jacobite rebellion.

His drawing of Castle Kennedy was so detailed that it revealed the layout

of pathways, borders,

plants and the clear outline of a fish pond at the end of the garden.

The ghostly crop marks photographed by Marilyn had revealed a moment in

time when gardens were planned along formal lines.

Regimented, in strict geometric shapes.

Gardens like this were very fashionable in the 17th century.

They give us an insight into the mind-set of the past.

Nature wasn't there to be enjoyed, but controlled and ordered.

The garden was Dalrymple's pride and joy,

but then he did something rather unexpected.

He destroyed it.

The reason for this rash decision is to be found in the crumbling ruins

of Castle Kennedy.

In 1716,

Sir John returned from Paris where he had been working as Britain's

ambassador to the court of Louis XV.

He found a smouldering shell.

One of his maids had set the building alight,

trying to dry bedding too close to an open hearth, and the fire

had gutted the place.

But Dalrymple didn't see a disaster - rather an opportunity.

In the age of Georgian Britain, tastes were changing.

Nature was now a thing to be celebrated, and formal gardens

were becoming old-fashioned.

Instead, landowners began to create gardens

that romanticised wilderness.

So Dalrymple created a magnificent new garden,

with the ruined castle as its centrepiece.

Right, here we are. So, where are we now?

We are in the central part of the building,

where all the main living areas would have been.

Lady Emily Stair has researched the history of Dalrymple's garden and

she and her husband are the current custodians.

He was a very creative individual.

He had an extraordinary career as a soldier, as a politician,

but had a fallow period, and in those years

he devoted himself to improving this place.

He was very much inspired by Versailles and the other gardens

he'd seen in France and he devoted

his time and energy to creating the landscape as it is.

He made use of the troops that were stationed nearby and they

created the extraordinary earthworks,

created the walled gardens and all that they could produce.

In the days of picks, shovels, horses and carts,

the new garden was a massive undertaking.

Two whole regiments were enlisted for the backbreaking task.

The work took around 15 years and involved the movement of huge

amounts of earth to create these banks and terraces.

Terraces that were designed specifically to view the new gardens

from above.

From up here, visitors could admire the new perfectly circular

fish pond, substantially bigger than the last one.

Behind the ruins of the castle, they could stroll through a walled

garden, planted with exotic flowers, herbs and fruit trees.

Either side of the gardens,

they could gaze across two huge bodies of water,

the White Loch and the Black Loch.

The two joined together by a new canal.

The Castle Kennedy makeover was a triumph, but in the process,

the old formal gardens had been consigned to history.

And it's only on hot summer days that its bones can occasionally be

glimpsed, like the ghost of gardens past.

Since aerial archaeologists first took to the skies, while

the planes and lenses have improved, the simple technique of pointing

the camera out of an open window hasn't changed.

But now, they are armed with a new device. Above the Isle of Arran,

state-of-the-art technology is probing the landscape in much

greater detail than ever before.

By criss-crossing an area of land and firing laser beams down at the

Earth, echoes are captured to produce a picture of the ground

that's accurate almost to the millimetre.

Trees, bushes, even forests are no barrier to receiving measurements.

Branches and undergrowth are stripped away

to reveal the naked earth.

Airborne laser scanning has revolutionised the job of aerial

archaeologists like Dave Cowley of the National Collection.

So, Dave, can you tell me what it is we are seeing here?

What we are seeing, Jamie, is a digital terrain model of the whole

of Arran. It's captured the surface topography, the goat fell,

the craggy north end, the much lower-lying south end,

as a digital surface. What does this show us that perhaps

we have never been able to see before?

Well, where do I start?

If we have a look at some of the existing aerial photography,

immediately we are seeing a couple of prehistoric roundhouses.

There's a couple of those fairly clearly,

but when we switch off the photographs and start to move

towards the airborne laser scanning-based visualisations,

we can see the two hut circles we have looked at earlier,

the two roundhouses. What we are seeing immediately is

that there are lots and lots of other

examples. Straightaway, I can see ten or 20 new sites, potentially.

Oh, absolutely.

These little small agricultural clearance cairns,

bits of field boundaries and so on.

This must be tremendously exciting to you as an archaeologist.

Yeah, this is absolutely the business.

This really is the stuff of dreams and it is an absolute game-changer

in terms of being able to cover something like the whole land mass

of Scotland within my lifetime.

Stand on Arran, even in its remotest parts, and the chances are that you

cannot move for tripping over some trace of human activity.

When lasers strip the landscape bare,

you can see just how much our interventions have,

from the earliest times,

marked, changed and scarred our world.

At the end of the 19th century, we thought there were only 21

important ancient sites across the whole of Scotland,

but thanks to the work of pioneering aerial archaeologists,

that list has grown into hundreds of thousands.

And we care more about protecting them than ever before.

And we keep on building them.

Here is an aerial photograph of Edinburgh and Arthur's Seat,

taken in 1951.

The Palace of Holyrood stands to this day,

but the gasworks, two breweries and much of the housing have all gone.

Standing in their place,

modern apartments and a new Scottish Parliament.

A statement built in steel, glass and stone.

It demonstrates our ability to rewrite our landscape.

Over the past century, the pace of change has been incredible.

We can see our homes, our cityscapes,

our landscapes, change around us.

We keep rewriting our landscapes, we can't stop it, it's in our nature.

Aerial photography allows us to follow the clues back into the past,

to see who we once were, and also asks the question,

what other secrets are out there waiting to be discovered?