Horizon

London's Natural History Museum

is one of the world's most prestigious institutions.

Since it opened in 1881,

over 600 million visitors have passed through its doors.

It's a spectacular monument to Earth's biodiversity.

And since 1979, a dinosaur, Dippy the diplodocus,

has welcomed everyone as they enter the main hall.

He's one of the museum's most adored attractions.

I'm very closely attached to him.

But in 2015,

the museum took the controversial decision to call time on Dippy.

It announced that the hall was going to be given a new star attraction,

one that has been here, gathering dust, for over 100 years.

The skeleton of a huge blue whale.

Wow. I know! It's amazing, isn't it?

It's remarkable.

The museum wants to change its image

and has decided on a very ambitious way of doing so.

This is basically where the action's going to be. Yep.

But getting it there will be a truly extraordinary

engineering challenge. Er... You're tilting now.

And these are the people who have to make it happen.

Oops. That's it. The skull coming off, that's my worst nightmare.

Horizon has been watching behind-the-scenes

in the Natural History Museum for over two years...

Whoa, whoa, whoa! Whoa, whoa, whoa!

The skull is currently 14 centimetres too large

to fit in this door, as it currently stands.

...following two giants of natural history,

a dinosaur and a blue whale...

And we're on the beach that the blue whale beached on, back in 1891.

...and one audacious dream.

Why are we doing this again?

The Natural History Museum

is renowned for its scientific research

and world-class collections.

And for the last 38 years,

Dippy the dinosaur has been standing centre stage.

Lorraine Cornish, the museum's head of conservation,

has been responsible for looking after him for all that time.

What we're doing today is cleaning Dippy,

which is a regular process,

takes place every six months or so.

Lorraine has been caring for the museum's exhibits for over 30 years.

I initially started working in a laboratory downstairs,

but soon I was allowed to come up and work in the galleries,

on the objects on display, and that was always deeply satisfying,

because you knew any work that you were going to be doing,

the public would see.

And she has a special place in her heart for Dippy.

I'm very closely attached to him,

because he was put into this gallery just the year before I joined

the museum, so we've had a similar amount of time together here.

What many people don't realise is that Dippy is not a real fossil,

he's a plaster replica.

However, this hasn't stopped him

amazing visitors ever since he arrived.

Let's see if we can find out how long it is.

Look up at its head there.

John, would you like to take a walk?

When you come to the end of his tail, you wave to us.

The plan to move Dippy hasn't gone down well with the public.

It's just, it's always the first thing you expect to see when you walk in.

I mean, we'd rather the dinosaur stay there.

But the museum is hoping that its new major exhibit

will eventually be as much-loved as Dippy.

Richard Sabin has been the curator of the museum's marine mammal

collection for the past 24 years

and is one of the world's experts on whales.

It was he who championed the idea to have a whale replace Dippy.

Hintze Hall has always been

a dynamic space. Over the life of the Natural History Museum,

from 1881, the central displays have changed.

When I first visited the museum in 1976, before Dippy was in place,

there were other specimens in there, elephants...

Erm, there'd been a sperm whale skeleton in Hintze Hall in the past.

Hintze Hall is the grand entrance of the museum

and was designed to dazzle the visitor

with the beauty and complexity of the natural world.

I think with the blue whale, when people see this enormous skeleton

in that wonderful architectural space,

I think very quickly, any critics that we have will be silenced,

and, you know, children and their children over the next 20-30 years

will come to accept the blue whale skeleton

as the new iconic central specimen for the museum.

As the skeleton of the world's biggest animal,

and one of its most endangered,

the museum wants the whale to be a reminder of humanity's delicate

relationship with the natural world

and our responsibility to care for all life on Earth.

Jennifer Flippance is the project manager in charge

of the whale's move into this historic space.

It looks like a really big hall.

The entrances are actually very small,

and it's going to be quite tight on the day that we bring it in.

It's Jen's job to fulfil Richard's ambitious dream

and hang the whale from the girders in a new, exciting way.

This is basically where the action's going to be. Yep.

I mean, the idea is that we give the skeleton a lot more dynamism

than it has currently, cos at the moment, it's kind of, you know,

stamp collector's pose. Yeah, yeah.

Very horizontal. Very Victorian, actually.

We need to build in as much kind of movement,

implied movement as possible. Yeah.

I'm just imagining that specimen kind of swimming through the space

and imagining it diving down towards the visitors as they come in through

the entrance. That will look really dramatic, too. Exactly.

Mouth wide open, you know?

People walking in have this great spectacle, oohs and ahs.

Suspending the bones of the whale will be a truly unique challenge.

It's going to be a feat, I think, of engineering... Mm.

...to be given a frame that's going to allow us to do the things

that we want to do.

And certainly, if we put the degree of dynamism into the specimen

that I'm hoping we can, it's going to include things like, you know,

a lot of curvature in the vertical column,

the tail sort of flexing up, the flippers out. OK, so...

All the things that we don't have currently, basically.

But it's going to be incredible, I think, absolutely incredible.

Inspire a new generation of marine biologists.

Yeah. That's we want.

Yeah, we want the same kind of kick for the new marine biologists

that I had as a kid.

Jen is in charge of overseeing all the staff

and ensuring everything is completed in time for the grand opening.

The pressure is certainly on.

We're doing a lot things we haven't done before, and I'm doing

a lot of things I haven't done before as a project manager.

It does give you some nervousness doing things,

and there's a big health and safety element, obviously,

which is probably my biggest concern overall,

getting it down safely and putting it back up so it's safe.

So that's certainly a thing that would keep me awake at night.

The first thing Jen needs to do is to get Richard's skeleton down

in one piece.

Not an easy job, considering it hasn't been moved for over 70 years.

Richard and Lorraine are anxious to see what state the whale is in.

This is the first time they've been able to get an idea

of the condition of her bones.

Dust. Wow! I know!

It's amazing, isn't it?

It's remarkable. I know.

You've just got this fantastic, thick carpet going all the way.

Due to the proximity of other exhibits in the hall,

and the delicate nature of the ever-ageing bones,

this skeleton will have to be painstakingly dismantled

piece by piece.

This is just going to be great.

The team can't wait to start.

Before it can be brought down...

That will disappear, that will look so much more beautiful.

Don't worry.

...Lorraine has been joined by conservator Ari

to help with the cleaning and tagging

of every one of the 220 bones.

They will then have to reinforce the weaker bones

before the dismantling can even begin.

Um, it's very unique,

so you do want to make sure that you are doing everything properly.

You want to make sure you catch every single sign of weakness,

so that you can stabilise it,

so that it can come down safely and it isn't damaged.

With the skull now free of dust,

Richard is able to examine it in detail.

The one thing that you need to remember

when you look at this lower jawbone

of this beautiful blue whale specimen

is that this is the largest single bone to be grown

by any organism on the planet that we know of.

I find that quite remarkable.

This is an incredibly special experience,

I think for me or anyone,

because I'm seeing things that I've never seen before.

The lead members of the team who put this skeleton together

actually left their signatures.

When they finished their work in February 1934,

they decided, like a great work of art, to leave their signatures.

And they're under...

...the skull, on the inside, by this metal strap.

You can see the signatures of four of the men who worked.

It's quite a nice little dedication, I think.

It took 20 men six months to hang the whale,

without today's strict health and safety regulations.

Looking at some of the photographs, those men took incredible chances.

They were working off long ladders, wooden ladders, using ropes,

standing on the specimen.

You know, they didn't have safety gear.

They wore flat caps and leather aprons.

They really were different times.

It was sort of before health and safety existed.

But they did a great job. We can't criticise them for that.

Back in the 1930s, it would have been a huge challenge

to hang this 4.5-tonne whale in a flat pose.

But Richard wants something even more difficult.

He wants the new exhibit to amaze visitors

by capturing how these animals behave in the wild.

Blue whales can weigh up to 200 tonnes

and measure up to 30 metres in length.

They're not only the biggest animal on Earth today,

they are, as far as we know, the biggest ever to have existed,