Drain the Oceans

The wild seas of Europe's far north.

For centuries, a global centre of trade.

And home to wealthy, powerful nations.

Their success relies on one thing above all others:

Mastery of these storm-tossed waters.

Through astonishing seamanship,

and groundbreaking design,

It begins with a people

whose name strikes terror across all Europe:

The vikings.

From their heartlands in Scandinavia, the vikings build extraordinary

sailing ships and use them to raid and conquer,

reaching even the shores of north America.

So revered were these ships that the vikings buried their great kings inside them.

What was the secret of their success?

This quiet field in Southern Norway may provide an answer.

A huge burial mound, hinting at a deeper history.

It's so exciting.

It's one of the biggest we have in Scandinavia.

And that's why we wanted to go into this area.

Previous excavations here have found little.

Now, armed with the latest scanning technology, archaeologist Knut Paasche,

and his team, probe the site.

As the ground starts giving up its secrets, they identify 11 more burial mounds.

And then the motherlode.

But there's no doubt what it is.

We have the shape.

It's definitely a ship.

Very little is known about the viking longships

of the eighth and ninth centuries.

Just a few images past down, and a handful of archaeological relicts.

Our main problem today is that we have so few left,

so we don't know what did they actually look like.

Of the thousands of viking ships that once sailed the oceans,

just four have been found in Norway.

Knute hopes this could be another.

Well you don't find things like that every day.

When we recognised, whoa, this is actually a ship, then it was wow!

And now armed with his scanning data, we can remove the soil,

peel back the sediments of time and reveal what lies beneath.

Hidden one and a half feet below ground, an unmistakable outline.

Almost 65 feet long.

Large enough for a crew of 30 men.

Made up overlapping oak timbers, joined by nails.

And this a flat, rectangular structure towards the centre of the ship.

The burial mounds are in the south east of Norway,

close to where other buried viking ships have been found.

Those are roughly the same size and design.

It's very comparable to the others.

Then you have the length, the width and the depth of the ship as well.

For Knut, it can mean only one thing.

There's no doubt, it is a viking ship.

Knut wants to learn more about this 1,000 year old vessel,

to understand the secrets of viking ship design,

and learn how this race of seafarers mastered the wild seas of Scandinavia.

First, he recognises the overlapping plant construction.

It's a style known as clinker built.

Oak planks fastened together with iron rivets.

A design that's water proof, and gives viking ships the flexibility they need

to stand up to the power of the northern seas.

This construction, first of all it's flexible.

That's very, very important.

It's not as stiff as you can see at other wooden boats or ships further south.

Not fighting the weather, but actually go with it.

Knut turns his attention to the flat rectangular structure,

sitting in the heart of the vessel.

Its location at the centre of the ship is a clue.

It must have once supported a large mast and sail

key breakthroughs in ship design.

A simple rowing boat could never traverse these seas.

Knut also notes the shape and position of the flat structure,

cleverly placed to distribute the huge forces on the sail

down into the frame of the ship,

allowing viking expeditions to withstand even Gale force winds.

They have all these details in the ship that they have used hundreds

of years to learn how to build them,

and that's why they actually could survive out there.

But these details alone can't explain the vikings legendary ability

to navigate the stormiest oceans and even the wild Atlantic.

A piece of the puzzle is missing.

And to find what that is, Knut's come here

to study the most beautifully preserved viking ship ever found.

Discovered close to the Oslo fjord, at 70 feet long,

it's similar in size and construction to his own discovery.

You have these beautiful lines going downwards.

They're not only beautiful.

This is actually really important.

And beyond the strength and flexibility of the ship's unique

wooden construction, there's something else.

Its hydrodynamic profile.

The vikings were centuries ahead of their time

in understanding the principles of streamlining

and how to keep a ship riding on top of the waves.

When you meet the waves,

the ship should actually swallow the waves with it.

The water should go underneath and lift the ship in the middle and the water

should be pushed out in the back.

The design that lies behind the viking legend is now clear.

Brilliantly engineered to skim across the most violent waters.

A sleek, ocean raider built for exploration and conquest.

Capable of taming the wild oceans, wherever they may be.

Knut has cracked the DNA of his buried ship's design,

but there is still one final puzzle.

Like the ancient Egyptians before them, ship burial was an old viking custom.

Sending a dead king along with all his most treasured possessions

on a final journey to the afterlife.

Other burial ships have been found close to the sea, but this one is different.

I mean we are more than a kilometre away the sea here.

Why on earth have they brought the ship all the way in here?

Marine archaeologist Knut Passche wants to find out

why a buried viking ship has been found so far from the coast.

That has been a mystery.

It's not easy to carry more than 2 tons maybe of oak in here.

Norway's coastline of small inlets and deep fjords is the result

of millions of years of geological change,

especially the long ice age, when glaciers covered this land.

As Knut studies the pattern of that geological change,

he makes a surprising discovery.

During the viking era, the coastline here looked very different,

with the sea much higher than it is today.

And that means these fields were part of the fjord,

and this narrow stream running all the way up

towards the burial site,

was a river.

Norway's changing geology explains why Knut's vessel lies so far inland.

You could actually row it into the river and up the creek.

It's now possible to understand exactly

what happened here 1,000 years ago, as the vikings

bring their most hallowed possession to be buried along with their fallen king.

With their longships designed for raiding and crossing oceans,

the vikings reach ever further.

Could the discovery of these circular stones hold the key to the next chapter

in the evolution of viking society, and of their ships?

Here close to the Southern tip of Norway is an ancient shipping route

used for centuries by seafarers to travel along the coast

protected from the worst of the weather.

This landscape is quite dramatic.

Something could have happened while they came in,

because it's very narrow through this sounds here.

It's here that the chance discovery of some strange looking stones

could help explain how the viking way of life began to change.

A diver called and said yes, seen a lot of rounded stones with a hole in it.

Yes, I think that we have to check this.

With the stones just a short distance from the harbour,

the archaeological team sets out to make a thorough investigation of the channel.

We are going to a really advanced scanning of the sea floor

to look at the stones in more detail today.

Now, with those high resolution scans,

we can drain the shore of Southern Norway

to discover for the first time what lies beneath these waters.

A cluster of at least 26 stones, each one is made of hard rock,

is almost a foot in diameter and weighs around 75 pounds

perfectly round and with a hole drilled in the middle.

The team soon realizes they must be grindstones.

They came in pairs. You have one on the bottom

and you rotate the other one and you then can make flour.

Studying the site, the team notices something important.

The stones are strewn in a definite pattern, lying the length of a narrow ditch

at the bottom of the channel.

The way it looks is it tells us quite obviously that this has to be a wrecked ship.

A wreck whose wooden remains have completely rotted away.

The total extent of the site is about 18 meters,

probably something has shifted so but it indicates

that this has been a fairly large ship.

The team now wants to discover what kind of ship it was.

With the hull missing, that's going to be difficult.

Then, they find something.

A reindeer antler, often traded from Norway and used to make combs or needles.

To the scientists, it's an important clue.

This is the antler that we managed to pull out from the wreck site.

As we can see, it's the thickets part of the reindeer antler

and this is chopped off in both ends.

By carbon dating the marrow inside the bone, they're able to date it

to the final decades of the viking golden age.

You don't need grindstones for raiding and pillaging.

Why so many?

The team realizes they had to be some form of valuable cargo.

This was definitely a part of the cargo and probably an item

that was for sale, that they were going to deliver to somewhere.

Using the footprints of the stones,

as they reconstruct the shape of the vessel,

it becomes clear this was wider than the traditional viking longship and deeper.

Large enough to carry those stones.

A new direction in viking design: A viking cargo ship.

So what can this cargo reveal about how the vikings built

and secured their long term success?

He bottom of a channel in Southern Norway,

this cargo of grindstones could reveal something new about viking trade.

I find this site really exciting

because it's the first sort of ocean going trade vessel

that we have found in Norway underwater.

So I'm really hoping to see where it had been, where it came from, where it was going.

Careful examination of the grindstones reveals they had been deliberately

hewn from a very particular type of rock.

A kind of schist that carries a unique geological signature,

and using that signature, the team is able to trace it back

Hyllestad, in western Norway.

By sea, a journey of over 300 miles

a distance that only reinforces the theory

that these had to be valuable items for trade