St Paul's Cathedral Climbing Great Buildings

I'm close up and personal with one of Britain's most iconic landmarks -

St Paul's Cathedral.

The masterpiece of Sir Christopher Wren, a marriage of engineering and religion like no other,

which epitomises the age in which it was built,

a time that many have called the Age of Enlightenment.

This is Climbing Great Buildings. Throughout this series,

I'll be scaling our most iconic structures, from the Normans to the present day.

I'll be revealing the buildings' secrets and telling the story

of how British architecture and construction developed over a thousand years.

The next step on my journey

through the evolution of British architecture brings me here, to St Paul's Cathedral.

If one structure captures the spirit of London, this is it.

Beautifully crafted and designed, it's simply stunning in its grandeur.

St Paul's is one of Britain's most recognisable buildings,

but its familiar exterior disguises a series of architectural illusions, which I'm going to expose.

In order to reveal the secrets and technological advances

that famous architect Sir Christopher Wren made in constructing this masterpiece,

I've been given unprecedented access to get a perspective of the building never seen before.

The painting up here! Look at it!

I'll be scaling over 300 feet up this vast cathedral

to reveal the secrets of how Wren built this magnificent structure with its iconic dome.

And that will test the limits of my courage.

Oh, my gosh! I have now re-learned fear.

I'll be abseiling down 225ft to gain a unique perspective of Wren's masterpiece.

That's amazing, the way that opens up.

But I won't be going it alone.

One of Britain's top climbers, Lucy Creamer...

and a team of riggers, along with fearless cameraman Ian Burton,

will be joining me on my vertical adventure.

That is probably the maddest thing I've done in my life.

I'm hoping to get an insight into the parts of the cathedral

we don't normally see. Behind that elegant and familiar facade

there's a lot of hidden history and some real architectural and engineering trickery.

St Paul's origins lie in the devastation caused by the Great Fire of London in 1666.

Over 13,000 homes and nearly 100 churches,

including the original St Paul's Cathedral, were burnt to the ground.

To create a fitting symbol of the resurrection of London,

King Charles II turned to bright young architect Christopher Wren.

The population of the city saw this massive cathedral rising from the ashes, bringing London back to life.

Well, it's not every day you get to climb an international icon, is it?

Wren is a man of legendary genius, an engineer, astronomer, mathematician and architect.

And so the way he used all of that knowledge and skill, I want to see up close.

Wren created a masterpiece of classical design, drawing on the elegant proportions of Ancient Rome.

But Wren was also an architectural illusionist

and St Paul's conceals an array of tricks that enabled him to build this wonderful monument to God.

In order to reveal the secrets, I need to get climbing.

My journey begins on the south wall of the cathedral,

where construction began nearly a decade after the Great Fire.

-Here we go.

-Yeah.

I've been really looking forward to climbing this building.

The outer walls are constructed of white Portland stone and rise nearly 100ft into the air,

the perfect place to start.

St Paul's is a relatively new building, compared to some of the buildings we've been on.

But the stone, it just looks so well preserved.

It looks really clean and there's nothing sort of flaking off.

Well, in the 17th century, we start to have Portland stone

being quarried from Dorset and then carried around the English Channel.

It's a Jurassic limestone, about 200 million years old.

-But it has such a fine grain that it's excellent for carving.

-Yeah.

One reason you'd use it in London is it takes pollution quite well.

Portland stone became the favourite stone for London. So Wren chose Portland every time, if he could.

The bright white stone of St Paul's radiates across the London skyline.

But getting it to the capital was a logistical challenge for Wren and his masons.

Brought in by boat up the Thames, it was unloaded at St Paul's Wharf.

Although that's only 200 yards away, it could take up to a week to lug the larger stones up to the site.

But the effort was worth it.

Over 300 years later, St Paul's is still a defining landmark of London.

Gosh, every move you make, something else comes into view, doesn't it?

The stonework is amazing. It's like wood carving that just happens to be in stone.

What I can't get over, though, is the size. From the ground,

-you just don't get an idea of the scale.

-You don't get it at all.

The cherub, he's just massive!

From the ground, he looks perfectly in proportion, doesn't he?

And his eyeballs are rolling as if he's in ecstasy, one would have thought, in the presence of God.

But up here, he looks rather chubby and drunk and the worse for wear!

Yeah!

-Nearly there.

-That's a heck of a ledge that, isn't it?

In the climbing world, this would be known as a sting in the tail.

A sting in the tail?

St Paul's is built on such a huge scale, even the ledge I have to negotiate my way over is 4ft wide.

-That's not a bad view already, is it?

-It's great!

-Right, where are we going?

-We're going this way.

The building of St Paul's stood as a symbol of hope for London and Wren commissioned beautiful sculptures

all over the cathedral, which depict stories and allegories.

You might expect the main western facade of St Paul's

to have an image of St Paul himself, and you wouldn't be disappointed.

In the pediment above me is a beautiful sculpture

which shows the moment of St Paul's conversion on the road to Damascus.

There's modern history as well.

On the south front is a giant phoenix and, of course, that's all about the Great Fire of London,

which destroyed the old medieval cathedral and left it, really,

a broken shell, full of ashes, from which Wren's masterpiece arose.

On the top, you'll see gilded flames, and the flames are shown

blowing in the direction the wind was blowing on that fateful September, 1666.

Messages everywhere.

Christopher Wren wanted this cathedral to be a showcase

for the ideas and exquisite crafts of the new Age of Enlightenment.

Wren searched in England and abroad for the finest artists and craftsmen to work on his masterpiece.

Detailed drawings of Wren's architecture are housed at the cathedral.

Sir Christopher Wren is the name associated with St Paul's,

-but this building is a testament to very many craftsmen.

-That's right.

Wren picked out the best people in their fields for the work.

-Who were they?

-Well, for woodwork, Grinling Gibbons was the man for the really high quality carving.

This shows the north side of the choir, in which is some of Grinling Gibbons' carving work.

It shows the Archbishop's chair in the middle, which has the phoenix emblem.

The phoenix became something of a symbol for the cathedral,

rising again after the Great Fire of London.

But it shows just how complicated some of the carving work was.

But in terms of the stonework, we're now looking at an elevation of the Dean's door.

Quite ornate in its details.

Yes, it's one of the finest pieces of carving on the exterior of the cathedral.

On this triangular pediment, the cherubs and the hanging foliage

was carved by William Kempster, who was one of Wren's master masons.

Kempster also designed the geometric stair from the cathedral floor...

-That's an enormous helter-skelter of a staircase.

-An amazing architectural space.

After negotiating my way along the 4ft ledge,

I'm about to ascend the second stage of St Paul's 93ft high outer wall.

Wren was the master of architectural trickery and looking at St Paul's from the ground,

you don't realise that everything is not quite as it seems.

-Shall we? Stage two?

-Shall we?

I'm climbing to the roof to reveal some of Wren's architectural secrets.

Upwards we go.

St Paul's is built on a colossal scale.

The bottom of the outer walls are 16ft thick and from the outside,

the cathedral looks like it's built of solid stone.

But in fact, it's a trick used by Wren to save money

as only the outer skin is made of the expensive Portland stone.

If you were to take away some of these Portland stones, you would find the blasted, charred remains

of the medieval cathedral from the Great Fire of London.

So they were recycling, even then?

Recycling, which is doing pretty much what the medieval builders did

when they had a fair skin inside and outside and put any old rubbish, mortar, old stone in the middle.

But there's a puzzle. The top 30ft of this classically designed wall

is only 4ft thick, nowhere near as thick as the bottom.

The answer to why lies on the other side of the wall.

Excellent, there's a hand hold.

Well, it's just another of Wren's architectural illusions.

The top of the wall is a screen to hide what lies behind.

Oh, wow! This isn't what I was expecting at all!

-There's nothing here.

-It's funny, isn't it?

You can't tell outside or inside the cathedral that this giant void exists

between the outside wall and the high vaults.

The front walls need to be massive, because they bear

the weight of the cathedral's vaults via flying buttresses.

The reason that Wren has this canyon on either side of the vaults

is because he's essentially using a medieval technique of structural support.

Those flying buttresses are the kind of things we saw in Durham and Lincoln.

But in the 17th century, in an age when you're supposed to build a classical looking cathedral,

what do you do? Look at St Peter's in Rome, you don't see any flying buttresses there.

Wren was building a traditional, in a sense, a medieval form

with aisles and high vaults, and yet he wants classical style.

So he builds this screen to pretend that those flying buttresses don't exist.

It was criticised at the time. You can't help but think he's being just a bit of a cheat. A clever one.

Let's get on, because the dome looks good from here, doesn't it?

Yes, let's check it out.

But before I climb up the dome of St Paul's,

I want to have a closer look at the material that Wren used to cover it, and the cathedral's other roofs.

Up on the roof, you can't help but be struck by the sheer acreage of the lead.

It's quite heavy stuff, but there's no real alternative.

What else are you going to cover a roof of this size with?

Copper might have been an option, and in fact, the copper lobby fought

to have the dome itself covered in copper.

And that would have gone that green colour. It is one of the defining colours of London.

But you can't help but look at that and be glad that lead was used.

This is soft oxide, which gives it that lovely blue, silver colour that works so well with the stone.

The lead workers who restore the roofs today use similar techniques to Wren's original craftsmen.

Are your tools similar to the ones that Wren's plumbers used?

Yeah, they'd have had exactly the same thing. It's the same process.

What are your tools called?

-That's my bossing mallet. That's my setting-in stick.

-Setting-in stick?

Yes. This outlines the corner.

I put the creases in where I'm going to boss up and form that corner.

OK. You're going to "boss up"? I love all these words!

It just put a crease in the lead,

which...makes it easier to bring up.

So why choose lead? Why is it better than other metals?

It might be possibly more expensive, but it is so versatile.

You can literally form any shape you want out of it, and it lasts for hundreds of years.

The wonderful lead-covered dome is St Paul's most iconic feature.

It's dominated London's skyline for over 300 years.

But its secret isn't obvious.

The only way to reveal Wren's ingenuity is by climbing up the dome to get inside.

The overall height of this thing is 365 feet. We're not going to go right to the top, are we?

It's going to take us to where the lead roof of the dome starts.

We can't actually climb that because it's probably a bit too fragile.

Well, we'll get inside and have a look. But it's an amazing scale.

If you think about Lincoln Cathedral, which we climbed,

and you could see into neighbouring counties from Lincoln.

Lincoln, you could fit the whole thing, the whole central tower, inside this dome.

That's pretty crazy because that felt big.

Come on, let's do it.

BELL CHIMES

Very lovely to hear the bells ring over London.

All of the noise and the din of the city is lost in that sweet sound.

Nice to think of how those bells have regulated the life of Londoners

for three centuries.

The dome is the crowning glory of St Paul's Cathedral.

It's a fantastic example of Wren's engineering skills.

Wren created something unique, which is why St Paul's looks, ultimately, like no other -

to his and London's eternal credit.

OK, good to go, Luce. I just need to make it over the top.

Yeah, and then we're there.

That not chewing-gum, is it?

There's quite a lot of it, yeah. I've noticed that.

You mean someone sits up here with chewing-gum? They're maniacs.

That's not what you expect to find!

The pinnacle of architectural civilisation in London - you find chewing-gum.

Where's the justice?

When Wren came to build the dome several decades after construction began at St Paul's,

he was confronted by a problem.

He'd noticed that the parts of the cathedral which support the dome had started to subside

because the foundations were set on uneven geology, with clay, gravel and brick earth.

Wren, therefore, had to rethink the construction of his dome.

It couldn't be too heavy or it would collapse under its own weight.

Unwilling to compromise on the dome, he instead came up with a solution

that would become his greatest architectural trick.

Wren designed a unique triple-layered dome

which made it lighter without compromising its look and shape.

It was the first of its kind anywhere in the world.

Wren had to achieve two things with his dome -

to make it look round like a Roman dome

and to make it light so it doesn't continue to sink into the ground.

And that's where the three-layered dome comes in.

The first dome he built was the one that no-one really sees.

It's a conical one like a witch's hat, because pointed arches,

as Gothic builders knew very well, are nice and strong.

And the second one is the external one, the big dome, covered in lead,

supported internally by a forest of timber.

But a witch's hat from the inside would look ridiculous - far too pointy.

And so this is where real genius comes in.

Wren put inside a third dome, another hemisphere, but smaller than the exterior one.

This you would see from the cathedral floor.

When you walk in the cathedral, you would never know any different.

What a master of disguise!

The workings of all this engineering brilliance can be seen in the space

between the outer dome and the conical inner dome, a part of the cathedral no-one usually sees.

This is the interior of the dome of St Paul's.

It's an amazing space.

You look down there about 30 or 40 feet and you can see the fins which prop the whole thing at its base.

And just to have sat down and worked it out on paper and then to have been convinced that it would stand.

If we build it, it's not going to be a waste of time, money and materials

and potentially kill people if it collapses. I mean, that's such a...

stage to have found yourself in, to commit to build this thing.

And that's the outer wall of timber which carries the lead.

And then this oak frame

goes right up to this second dome of brickwork.

The cone which supports the lantern right on the top, 365 feet up.

And then inside that is a shallower saucer dome with paintings on.

That's what you see from inside the cathedral.

It's a masterpiece of illusion.

And to see behind the theatre set, to see the machinery itself, is quite phenomenal.

So now for the third, the innermost of Wren's three concentric domes.

Now it may be the smallest of them, but it ain't tiny.

It's actually of phenomenal scale.

I'm about 230ft above the cathedral floor.

Getting to see the sheer size of the interior from here brings home its sheer audacity.

He built it because this second dome, the brick witch's hat,

sails at such a steep pitch that, if you looked at it from the cathedral floor,

it would be too much in perspective. It would be receding too fast.

You have to build a gentler dome so that it seems the right proportion,

like a hemisphere from the inside.

Oh, my gosh!

I have now relearned fear.

I thought Lucy had taught me to get rid of all my climbing nerves,

but that's something.

I'm back to square one, I think.

Without doubt, this is my biggest challenge yet - abseiling down that canyon to the cathedral floor.

That is ridiculous.

I had no idea.

By abseiling down, I am following in Wren's path.

Toward the end of St Paul's construction he was in his 80s

and the only way for him to reach the dome to inspect it was to be winched up and down in a basket.

I can't help but wonder if he was petrified as I am.

-I've got to overcome that.

-It's really high.

-I know.

Luce, I'll tell you this, I'm a bit scared, really.

But we're on ropes.

The laws of physics might realise that this isn't possible.

This is the most frightening thing I've ever done.

The thought of getting a unique view of Wren's masterpiece spurs me on.

If you could get your foot down...

I feel like I'm a bit snagged.

Jonathan, this is crazy.

This whole thing is crazy.

Oh, boy! Don't even start looking down there, Luce.

No, no, I'm not. Don't worry.

This is ridiculous.

I don't like that at all.

Come in close to the wall.

Well done.

Brilliant. Good effort.

That's awful. That's really awful.

That's the worst bit.

Oh boy! It's a long way down there, Luce. Look at that.

You keep saying that and I'm trying not to.

'And now there's no going back.

'It's time for the descent.'

I hate this bit.

It lurches because the rope's so heavy.

Oh, my gosh! The way that opens up.

That's amazing.

That is probably the maddest thing I've done in my life.

But the painting up here... Look at it.

OK, we are moving.

We're doing it, man.

We're abseiling down the middle of St Paul's Cathedral.

Seeing the vast artwork in this magnificent dome has somehow calmed my nerves.

And suddenly I find I'm actually enjoying myself.

What Wren wanted here was something much more generic as a decorative scheme.

He wanted to see flora and fauna.

But instead the cathedral commissioners gave the commission

to Sir James Thornhill, the king's sergeant painter.

And in 1715, Wren, aged 83, had little strength left to argue.

It took Thornhill until 1721 to finish this scheme.

It's in remarkably good condition.

-Do you see the windows at the top?

-Yeah.

Because you get more light up there, there's a blueness to the light

and it makes it look much higher than it is.

-It's about 40 feet, I guess.

-Yeah, it does.

-Where we stepped off into the abyss.

-There's a weird sort of perspective.

But it does give you that sense of other-worldliness.

If you're building a place that cultivates a sense of heaven

and the world beyond, just that little glimpse does that.

I wonder if that's accident or design.

It's the kind of thing you can't tell from a model, isn't it?

You need the effect of space.

-I'm sure Mr Wren said he did it on purpose.

-Do you think?

-Oh yes.

-Yeah.

We must be about halfway now, Lucy, between top and bottom?

It's hard to tell. Those chairs, those people still look pretty small.

They do look tiny.

Let's not focus on that. Let's look up.

This level's the famous Whispering Gallery.

If you walk out through one of those tiny doors

and speak against the wall, then people around the perimeter can hear what you're saying.

-(It also works in the middle.

-Yeah, I'm definitely whispering.

(Scientifically proven.)

-Right, down we go, madam.

-Let's head off-ski.

-For a very brief time only, lap it up, Luce.

-I know.

Christopher Wren intended St Paul's to have a plain stone interior

decorated with carvings in keeping with the classical style.

But the Victorians added much more colourful and ornate decoration

which can be seen in the eastern end of the cathedral.

You really appreciate the architecture from this position

because you get a bird's-eye view of the whole of the cathedral floor.

You see Victorian mosaic work in the spandrels, between the arches.

Quite painterly in style. And the bits of gold work,

angled so that they catch the light. It's a very exotic, Eastern take.

It's being able to see the vaults at the same time and the dome.

You seem to be in close proximity to everything.

Yeah, you've sort of got a perspective on the whole building.

Wren lived just about long enough to see his monument finished. The sculpture wasn't all completed.

It was 1723 when he died. He was aged 91, a grand man who contributed

so much to science as well as to architecture.

He was really the person who brought in the Georgian age and England would never look the same again.

He was buried here at St Paul's,

right beneath our feet.

And you can read that inscription.

"Christopher Wren.

"Lector, si monumentum requiris circumspice."

"Reader, if it's a monument you want, look around you."

And this is the place to look from.

-That was...

-It was extraordinary, wasn't it?

Yeah. I'm almost speechless.

I'm really chuffed with that.

I wish I could commit that to memory for all time.

A true one-off experience. You know, it's a familiar landmark.

You think you know St Paul's because you've seen the dome from the outside. It's that iconic shape.

But the irony is there's so much more to it.

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