0:00:02 > 0:00:04I'm close up and personal with one of Britain's most iconic landmarks -
0:00:04 > 0:00:06St Paul's Cathedral.
0:00:06 > 0:00:11The masterpiece of Sir Christopher Wren, a marriage of engineering and religion like no other,
0:00:11 > 0:00:14which epitomises the age in which it was built,
0:00:14 > 0:00:17a time that many have called the Age of Enlightenment.
0:00:19 > 0:00:22This is Climbing Great Buildings. Throughout this series,
0:00:22 > 0:00:27I'll be scaling our most iconic structures, from the Normans to the present day.
0:00:28 > 0:00:32I'll be revealing the buildings' secrets and telling the story
0:00:32 > 0:00:37of how British architecture and construction developed over a thousand years.
0:00:43 > 0:00:46The next step on my journey
0:00:46 > 0:00:51through the evolution of British architecture brings me here, to St Paul's Cathedral.
0:00:52 > 0:00:57If one structure captures the spirit of London, this is it.
0:00:57 > 0:01:01Beautifully crafted and designed, it's simply stunning in its grandeur.
0:01:04 > 0:01:07St Paul's is one of Britain's most recognisable buildings,
0:01:07 > 0:01:13but its familiar exterior disguises a series of architectural illusions, which I'm going to expose.
0:01:16 > 0:01:20In order to reveal the secrets and technological advances
0:01:20 > 0:01:25that famous architect Sir Christopher Wren made in constructing this masterpiece,
0:01:25 > 0:01:30I've been given unprecedented access to get a perspective of the building never seen before.
0:01:30 > 0:01:33The painting up here! Look at it!
0:01:33 > 0:01:38I'll be scaling over 300 feet up this vast cathedral
0:01:38 > 0:01:44to reveal the secrets of how Wren built this magnificent structure with its iconic dome.
0:01:44 > 0:01:46And that will test the limits of my courage.
0:01:46 > 0:01:50Oh, my gosh! I have now re-learned fear.
0:01:50 > 0:01:57I'll be abseiling down 225ft to gain a unique perspective of Wren's masterpiece.
0:01:57 > 0:01:59That's amazing, the way that opens up.
0:02:02 > 0:02:04But I won't be going it alone.
0:02:04 > 0:02:07One of Britain's top climbers, Lucy Creamer...
0:02:07 > 0:02:12and a team of riggers, along with fearless cameraman Ian Burton,
0:02:12 > 0:02:16will be joining me on my vertical adventure.
0:02:16 > 0:02:20That is probably the maddest thing I've done in my life.
0:02:26 > 0:02:31I'm hoping to get an insight into the parts of the cathedral
0:02:31 > 0:02:35we don't normally see. Behind that elegant and familiar facade
0:02:35 > 0:02:40there's a lot of hidden history and some real architectural and engineering trickery.
0:02:43 > 0:02:49St Paul's origins lie in the devastation caused by the Great Fire of London in 1666.
0:02:51 > 0:02:54Over 13,000 homes and nearly 100 churches,
0:02:54 > 0:02:58including the original St Paul's Cathedral, were burnt to the ground.
0:03:00 > 0:03:04To create a fitting symbol of the resurrection of London,
0:03:04 > 0:03:07King Charles II turned to bright young architect Christopher Wren.
0:03:09 > 0:03:16The population of the city saw this massive cathedral rising from the ashes, bringing London back to life.
0:03:19 > 0:03:23Well, it's not every day you get to climb an international icon, is it?
0:03:23 > 0:03:29Wren is a man of legendary genius, an engineer, astronomer, mathematician and architect.
0:03:29 > 0:03:34And so the way he used all of that knowledge and skill, I want to see up close.
0:03:38 > 0:03:44Wren created a masterpiece of classical design, drawing on the elegant proportions of Ancient Rome.
0:03:47 > 0:03:51But Wren was also an architectural illusionist
0:03:51 > 0:03:57and St Paul's conceals an array of tricks that enabled him to build this wonderful monument to God.
0:04:01 > 0:04:05In order to reveal the secrets, I need to get climbing.
0:04:05 > 0:04:09My journey begins on the south wall of the cathedral,
0:04:09 > 0:04:13where construction began nearly a decade after the Great Fire.
0:04:13 > 0:04:15- Here we go.- Yeah.
0:04:15 > 0:04:18I've been really looking forward to climbing this building.
0:04:21 > 0:04:27The outer walls are constructed of white Portland stone and rise nearly 100ft into the air,
0:04:27 > 0:04:29the perfect place to start.
0:04:29 > 0:04:35St Paul's is a relatively new building, compared to some of the buildings we've been on.
0:04:35 > 0:04:38But the stone, it just looks so well preserved.
0:04:38 > 0:04:41It looks really clean and there's nothing sort of flaking off.
0:04:41 > 0:04:44Well, in the 17th century, we start to have Portland stone
0:04:44 > 0:04:48being quarried from Dorset and then carried around the English Channel.
0:04:48 > 0:04:52It's a Jurassic limestone, about 200 million years old.
0:04:52 > 0:04:57- But it has such a fine grain that it's excellent for carving.- Yeah.
0:04:57 > 0:05:00One reason you'd use it in London is it takes pollution quite well.
0:05:00 > 0:05:06Portland stone became the favourite stone for London. So Wren chose Portland every time, if he could.
0:05:10 > 0:05:14The bright white stone of St Paul's radiates across the London skyline.
0:05:14 > 0:05:19But getting it to the capital was a logistical challenge for Wren and his masons.
0:05:19 > 0:05:23Brought in by boat up the Thames, it was unloaded at St Paul's Wharf.
0:05:23 > 0:05:29Although that's only 200 yards away, it could take up to a week to lug the larger stones up to the site.
0:05:31 > 0:05:33But the effort was worth it.
0:05:33 > 0:05:39Over 300 years later, St Paul's is still a defining landmark of London.
0:05:39 > 0:05:43Gosh, every move you make, something else comes into view, doesn't it?
0:05:43 > 0:05:49The stonework is amazing. It's like wood carving that just happens to be in stone.
0:05:49 > 0:05:53What I can't get over, though, is the size. From the ground,
0:05:53 > 0:05:57- you just don't get an idea of the scale.- You don't get it at all.
0:05:57 > 0:06:00The cherub, he's just massive!
0:06:00 > 0:06:03From the ground, he looks perfectly in proportion, doesn't he?
0:06:03 > 0:06:08And his eyeballs are rolling as if he's in ecstasy, one would have thought, in the presence of God.
0:06:08 > 0:06:12But up here, he looks rather chubby and drunk and the worse for wear!
0:06:12 > 0:06:14Yeah!
0:06:16 > 0:06:20- Nearly there.- That's a heck of a ledge that, isn't it?
0:06:20 > 0:06:24In the climbing world, this would be known as a sting in the tail.
0:06:24 > 0:06:26A sting in the tail?
0:06:26 > 0:06:32St Paul's is built on such a huge scale, even the ledge I have to negotiate my way over is 4ft wide.
0:06:35 > 0:06:40- That's not a bad view already, is it?- It's great!
0:06:40 > 0:06:43- Right, where are we going? - We're going this way.
0:06:45 > 0:06:52The building of St Paul's stood as a symbol of hope for London and Wren commissioned beautiful sculptures
0:06:52 > 0:06:56all over the cathedral, which depict stories and allegories.
0:06:58 > 0:07:01You might expect the main western facade of St Paul's
0:07:01 > 0:07:05to have an image of St Paul himself, and you wouldn't be disappointed.
0:07:05 > 0:07:08In the pediment above me is a beautiful sculpture
0:07:08 > 0:07:14which shows the moment of St Paul's conversion on the road to Damascus.
0:07:14 > 0:07:16There's modern history as well.
0:07:16 > 0:07:22On the south front is a giant phoenix and, of course, that's all about the Great Fire of London,
0:07:22 > 0:07:27which destroyed the old medieval cathedral and left it, really,
0:07:27 > 0:07:32a broken shell, full of ashes, from which Wren's masterpiece arose.
0:07:32 > 0:07:36On the top, you'll see gilded flames, and the flames are shown
0:07:36 > 0:07:42blowing in the direction the wind was blowing on that fateful September, 1666.
0:07:42 > 0:07:44Messages everywhere.
0:07:49 > 0:07:53Christopher Wren wanted this cathedral to be a showcase
0:07:53 > 0:07:57for the ideas and exquisite crafts of the new Age of Enlightenment.
0:07:57 > 0:08:04Wren searched in England and abroad for the finest artists and craftsmen to work on his masterpiece.
0:08:04 > 0:08:07Detailed drawings of Wren's architecture are housed at the cathedral.
0:08:07 > 0:08:11Sir Christopher Wren is the name associated with St Paul's,
0:08:11 > 0:08:15- but this building is a testament to very many craftsmen.- That's right.
0:08:15 > 0:08:19Wren picked out the best people in their fields for the work.
0:08:19 > 0:08:26- Who were they?- Well, for woodwork, Grinling Gibbons was the man for the really high quality carving.
0:08:26 > 0:08:31This shows the north side of the choir, in which is some of Grinling Gibbons' carving work.
0:08:31 > 0:08:36It shows the Archbishop's chair in the middle, which has the phoenix emblem.
0:08:36 > 0:08:38The phoenix became something of a symbol for the cathedral,
0:08:38 > 0:08:41rising again after the Great Fire of London.
0:08:41 > 0:08:44But it shows just how complicated some of the carving work was.
0:08:44 > 0:08:48But in terms of the stonework, we're now looking at an elevation of the Dean's door.
0:08:48 > 0:08:50Quite ornate in its details.
0:08:50 > 0:08:54Yes, it's one of the finest pieces of carving on the exterior of the cathedral.
0:08:54 > 0:08:58On this triangular pediment, the cherubs and the hanging foliage
0:08:58 > 0:09:03was carved by William Kempster, who was one of Wren's master masons.
0:09:03 > 0:09:08Kempster also designed the geometric stair from the cathedral floor...
0:09:08 > 0:09:12- That's an enormous helter-skelter of a staircase. - An amazing architectural space.
0:09:16 > 0:09:19After negotiating my way along the 4ft ledge,
0:09:19 > 0:09:25I'm about to ascend the second stage of St Paul's 93ft high outer wall.
0:09:25 > 0:09:30Wren was the master of architectural trickery and looking at St Paul's from the ground,
0:09:30 > 0:09:32you don't realise that everything is not quite as it seems.
0:09:32 > 0:09:34- Shall we? Stage two?- Shall we?
0:09:36 > 0:09:41I'm climbing to the roof to reveal some of Wren's architectural secrets.
0:09:41 > 0:09:44Upwards we go.
0:09:46 > 0:09:50St Paul's is built on a colossal scale.
0:09:50 > 0:09:54The bottom of the outer walls are 16ft thick and from the outside,
0:09:54 > 0:09:59the cathedral looks like it's built of solid stone.
0:09:59 > 0:10:02But in fact, it's a trick used by Wren to save money
0:10:02 > 0:10:08as only the outer skin is made of the expensive Portland stone.
0:10:08 > 0:10:14If you were to take away some of these Portland stones, you would find the blasted, charred remains
0:10:14 > 0:10:16of the medieval cathedral from the Great Fire of London.
0:10:16 > 0:10:18So they were recycling, even then?
0:10:18 > 0:10:23Recycling, which is doing pretty much what the medieval builders did
0:10:23 > 0:10:28when they had a fair skin inside and outside and put any old rubbish, mortar, old stone in the middle.
0:10:31 > 0:10:35But there's a puzzle. The top 30ft of this classically designed wall
0:10:35 > 0:10:39is only 4ft thick, nowhere near as thick as the bottom.
0:10:39 > 0:10:43The answer to why lies on the other side of the wall.
0:10:43 > 0:10:45Excellent, there's a hand hold.
0:10:47 > 0:10:50Well, it's just another of Wren's architectural illusions.
0:10:50 > 0:10:56The top of the wall is a screen to hide what lies behind.
0:10:56 > 0:11:00Oh, wow! This isn't what I was expecting at all!
0:11:00 > 0:11:02- There's nothing here. - It's funny, isn't it?
0:11:02 > 0:11:07You can't tell outside or inside the cathedral that this giant void exists
0:11:07 > 0:11:10between the outside wall and the high vaults.
0:11:10 > 0:11:14The front walls need to be massive, because they bear
0:11:14 > 0:11:17the weight of the cathedral's vaults via flying buttresses.
0:11:17 > 0:11:22The reason that Wren has this canyon on either side of the vaults
0:11:22 > 0:11:28is because he's essentially using a medieval technique of structural support.
0:11:28 > 0:11:32Those flying buttresses are the kind of things we saw in Durham and Lincoln.
0:11:32 > 0:11:36But in the 17th century, in an age when you're supposed to build a classical looking cathedral,
0:11:36 > 0:11:41what do you do? Look at St Peter's in Rome, you don't see any flying buttresses there.
0:11:41 > 0:11:45Wren was building a traditional, in a sense, a medieval form
0:11:45 > 0:11:49with aisles and high vaults, and yet he wants classical style.
0:11:49 > 0:11:53So he builds this screen to pretend that those flying buttresses don't exist.
0:11:53 > 0:12:00It was criticised at the time. You can't help but think he's being just a bit of a cheat. A clever one.
0:12:00 > 0:12:05Let's get on, because the dome looks good from here, doesn't it?
0:12:05 > 0:12:08Yes, let's check it out.
0:12:08 > 0:12:11But before I climb up the dome of St Paul's,
0:12:11 > 0:12:16I want to have a closer look at the material that Wren used to cover it, and the cathedral's other roofs.
0:12:19 > 0:12:24Up on the roof, you can't help but be struck by the sheer acreage of the lead.
0:12:24 > 0:12:27It's quite heavy stuff, but there's no real alternative.
0:12:27 > 0:12:30What else are you going to cover a roof of this size with?
0:12:30 > 0:12:34Copper might have been an option, and in fact, the copper lobby fought
0:12:34 > 0:12:37to have the dome itself covered in copper.
0:12:37 > 0:12:41And that would have gone that green colour. It is one of the defining colours of London.
0:12:41 > 0:12:44But you can't help but look at that and be glad that lead was used.
0:12:44 > 0:12:51This is soft oxide, which gives it that lovely blue, silver colour that works so well with the stone.
0:12:55 > 0:13:00The lead workers who restore the roofs today use similar techniques to Wren's original craftsmen.
0:13:03 > 0:13:07Are your tools similar to the ones that Wren's plumbers used?
0:13:07 > 0:13:11Yeah, they'd have had exactly the same thing. It's the same process.
0:13:11 > 0:13:13What are your tools called?
0:13:13 > 0:13:18- That's my bossing mallet. That's my setting-in stick.- Setting-in stick?
0:13:18 > 0:13:21Yes. This outlines the corner.
0:13:21 > 0:13:26I put the creases in where I'm going to boss up and form that corner.
0:13:26 > 0:13:29OK. You're going to "boss up"? I love all these words!
0:13:32 > 0:13:36It just put a crease in the lead,
0:13:36 > 0:13:41which...makes it easier to bring up.
0:13:41 > 0:13:45So why choose lead? Why is it better than other metals?
0:13:45 > 0:13:50It might be possibly more expensive, but it is so versatile.
0:13:50 > 0:13:55You can literally form any shape you want out of it, and it lasts for hundreds of years.
0:14:00 > 0:14:05The wonderful lead-covered dome is St Paul's most iconic feature.
0:14:06 > 0:14:11It's dominated London's skyline for over 300 years.
0:14:11 > 0:14:14But its secret isn't obvious.
0:14:16 > 0:14:22The only way to reveal Wren's ingenuity is by climbing up the dome to get inside.
0:14:24 > 0:14:29The overall height of this thing is 365 feet. We're not going to go right to the top, are we?
0:14:29 > 0:14:34It's going to take us to where the lead roof of the dome starts.
0:14:34 > 0:14:38We can't actually climb that because it's probably a bit too fragile.
0:14:38 > 0:14:42Well, we'll get inside and have a look. But it's an amazing scale.
0:14:42 > 0:14:45If you think about Lincoln Cathedral, which we climbed,
0:14:45 > 0:14:50and you could see into neighbouring counties from Lincoln.
0:14:50 > 0:14:54Lincoln, you could fit the whole thing, the whole central tower, inside this dome.
0:14:54 > 0:14:58That's pretty crazy because that felt big.
0:14:58 > 0:15:00Come on, let's do it.
0:15:02 > 0:15:05BELL CHIMES
0:15:09 > 0:15:13Very lovely to hear the bells ring over London.
0:15:13 > 0:15:18All of the noise and the din of the city is lost in that sweet sound.
0:15:19 > 0:15:25Nice to think of how those bells have regulated the life of Londoners
0:15:25 > 0:15:27for three centuries.
0:15:28 > 0:15:32The dome is the crowning glory of St Paul's Cathedral.
0:15:32 > 0:15:36It's a fantastic example of Wren's engineering skills.
0:15:36 > 0:15:43Wren created something unique, which is why St Paul's looks, ultimately, like no other -
0:15:43 > 0:15:46to his and London's eternal credit.
0:15:49 > 0:15:52OK, good to go, Luce. I just need to make it over the top.
0:15:52 > 0:15:55Yeah, and then we're there.
0:15:57 > 0:15:59That not chewing-gum, is it?
0:15:59 > 0:16:02There's quite a lot of it, yeah. I've noticed that.
0:16:02 > 0:16:07You mean someone sits up here with chewing-gum? They're maniacs.
0:16:07 > 0:16:08That's not what you expect to find!
0:16:08 > 0:16:14The pinnacle of architectural civilisation in London - you find chewing-gum.
0:16:14 > 0:16:16Where's the justice?
0:16:20 > 0:16:24When Wren came to build the dome several decades after construction began at St Paul's,
0:16:24 > 0:16:26he was confronted by a problem.
0:16:26 > 0:16:31He'd noticed that the parts of the cathedral which support the dome had started to subside
0:16:31 > 0:16:39because the foundations were set on uneven geology, with clay, gravel and brick earth.
0:16:39 > 0:16:42Wren, therefore, had to rethink the construction of his dome.
0:16:42 > 0:16:46It couldn't be too heavy or it would collapse under its own weight.
0:16:46 > 0:16:50Unwilling to compromise on the dome, he instead came up with a solution
0:16:50 > 0:16:54that would become his greatest architectural trick.
0:16:54 > 0:16:58Wren designed a unique triple-layered dome
0:16:58 > 0:17:01which made it lighter without compromising its look and shape.
0:17:01 > 0:17:05It was the first of its kind anywhere in the world.
0:17:08 > 0:17:11Wren had to achieve two things with his dome -
0:17:11 > 0:17:14to make it look round like a Roman dome
0:17:14 > 0:17:19and to make it light so it doesn't continue to sink into the ground.
0:17:19 > 0:17:23And that's where the three-layered dome comes in.
0:17:23 > 0:17:27The first dome he built was the one that no-one really sees.
0:17:27 > 0:17:31It's a conical one like a witch's hat, because pointed arches,
0:17:31 > 0:17:34as Gothic builders knew very well, are nice and strong.
0:17:34 > 0:17:39And the second one is the external one, the big dome, covered in lead,
0:17:39 > 0:17:42supported internally by a forest of timber.
0:17:42 > 0:17:47But a witch's hat from the inside would look ridiculous - far too pointy.
0:17:47 > 0:17:50And so this is where real genius comes in.
0:17:50 > 0:17:55Wren put inside a third dome, another hemisphere, but smaller than the exterior one.
0:17:55 > 0:17:59This you would see from the cathedral floor.
0:18:02 > 0:18:05When you walk in the cathedral, you would never know any different.
0:18:05 > 0:18:08What a master of disguise!
0:18:11 > 0:18:15The workings of all this engineering brilliance can be seen in the space
0:18:15 > 0:18:23between the outer dome and the conical inner dome, a part of the cathedral no-one usually sees.
0:18:24 > 0:18:29This is the interior of the dome of St Paul's.
0:18:29 > 0:18:31It's an amazing space.
0:18:31 > 0:18:38You look down there about 30 or 40 feet and you can see the fins which prop the whole thing at its base.
0:18:38 > 0:18:43And just to have sat down and worked it out on paper and then to have been convinced that it would stand.
0:18:43 > 0:18:49If we build it, it's not going to be a waste of time, money and materials
0:18:49 > 0:18:53and potentially kill people if it collapses. I mean, that's such a...
0:18:53 > 0:18:58stage to have found yourself in, to commit to build this thing.
0:18:58 > 0:19:02And that's the outer wall of timber which carries the lead.
0:19:02 > 0:19:05And then this oak frame
0:19:05 > 0:19:09goes right up to this second dome of brickwork.
0:19:09 > 0:19:14The cone which supports the lantern right on the top, 365 feet up.
0:19:14 > 0:19:19And then inside that is a shallower saucer dome with paintings on.
0:19:19 > 0:19:22That's what you see from inside the cathedral.
0:19:22 > 0:19:24It's a masterpiece of illusion.
0:19:24 > 0:19:30And to see behind the theatre set, to see the machinery itself, is quite phenomenal.
0:19:34 > 0:19:37So now for the third, the innermost of Wren's three concentric domes.
0:19:37 > 0:19:44Now it may be the smallest of them, but it ain't tiny.
0:19:44 > 0:19:46It's actually of phenomenal scale.
0:19:47 > 0:19:50I'm about 230ft above the cathedral floor.
0:19:50 > 0:19:57Getting to see the sheer size of the interior from here brings home its sheer audacity.
0:19:57 > 0:20:02He built it because this second dome, the brick witch's hat,
0:20:02 > 0:20:08sails at such a steep pitch that, if you looked at it from the cathedral floor,
0:20:08 > 0:20:12it would be too much in perspective. It would be receding too fast.
0:20:12 > 0:20:16You have to build a gentler dome so that it seems the right proportion,
0:20:16 > 0:20:19like a hemisphere from the inside.
0:20:20 > 0:20:23Oh, my gosh!
0:20:23 > 0:20:26I have now relearned fear.
0:20:26 > 0:20:31I thought Lucy had taught me to get rid of all my climbing nerves,
0:20:31 > 0:20:34but that's something.
0:20:34 > 0:20:37I'm back to square one, I think.
0:20:37 > 0:20:43Without doubt, this is my biggest challenge yet - abseiling down that canyon to the cathedral floor.
0:20:47 > 0:20:49That is ridiculous.
0:20:51 > 0:20:53I had no idea.
0:20:55 > 0:20:58By abseiling down, I am following in Wren's path.
0:20:58 > 0:21:02Toward the end of St Paul's construction he was in his 80s
0:21:02 > 0:21:07and the only way for him to reach the dome to inspect it was to be winched up and down in a basket.
0:21:07 > 0:21:11I can't help but wonder if he was petrified as I am.
0:21:15 > 0:21:18- I've got to overcome that. - It's really high.- I know.
0:21:18 > 0:21:22Luce, I'll tell you this, I'm a bit scared, really.
0:21:23 > 0:21:25But we're on ropes.
0:21:25 > 0:21:29The laws of physics might realise that this isn't possible.
0:21:31 > 0:21:34This is the most frightening thing I've ever done.
0:21:39 > 0:21:43The thought of getting a unique view of Wren's masterpiece spurs me on.
0:21:47 > 0:21:49If you could get your foot down...
0:21:49 > 0:21:50I feel like I'm a bit snagged.
0:21:56 > 0:21:57Jonathan, this is crazy.
0:21:57 > 0:22:00This whole thing is crazy.
0:22:06 > 0:22:08Oh, boy! Don't even start looking down there, Luce.
0:22:08 > 0:22:11No, no, I'm not. Don't worry.
0:22:15 > 0:22:17This is ridiculous.
0:22:17 > 0:22:20I don't like that at all.
0:22:20 > 0:22:21Come in close to the wall.
0:22:31 > 0:22:33Well done.
0:22:38 > 0:22:40Brilliant. Good effort.
0:22:44 > 0:22:46That's awful. That's really awful.
0:22:46 > 0:22:48That's the worst bit.
0:22:48 > 0:22:51Oh boy! It's a long way down there, Luce. Look at that.
0:22:52 > 0:22:56You keep saying that and I'm trying not to.
0:22:56 > 0:22:58'And now there's no going back.
0:22:58 > 0:22:59'It's time for the descent.'
0:23:04 > 0:23:06I hate this bit.
0:23:06 > 0:23:09It lurches because the rope's so heavy.
0:23:15 > 0:23:18Oh, my gosh! The way that opens up.
0:23:18 > 0:23:19That's amazing.
0:23:22 > 0:23:27That is probably the maddest thing I've done in my life.
0:23:33 > 0:23:35But the painting up here... Look at it.
0:23:40 > 0:23:41OK, we are moving.
0:23:41 > 0:23:44We're doing it, man.
0:23:44 > 0:23:47We're abseiling down the middle of St Paul's Cathedral.
0:23:49 > 0:23:55Seeing the vast artwork in this magnificent dome has somehow calmed my nerves.
0:23:55 > 0:23:58And suddenly I find I'm actually enjoying myself.
0:24:00 > 0:24:05What Wren wanted here was something much more generic as a decorative scheme.
0:24:05 > 0:24:07He wanted to see flora and fauna.
0:24:07 > 0:24:10But instead the cathedral commissioners gave the commission
0:24:10 > 0:24:12to Sir James Thornhill, the king's sergeant painter.
0:24:12 > 0:24:18And in 1715, Wren, aged 83, had little strength left to argue.
0:24:18 > 0:24:22It took Thornhill until 1721 to finish this scheme.
0:24:22 > 0:24:25It's in remarkably good condition.
0:24:31 > 0:24:35- Do you see the windows at the top?- Yeah.
0:24:35 > 0:24:38Because you get more light up there, there's a blueness to the light
0:24:38 > 0:24:40and it makes it look much higher than it is.
0:24:40 > 0:24:42- It's about 40 feet, I guess. - Yeah, it does.
0:24:42 > 0:24:46- Where we stepped off into the abyss. - There's a weird sort of perspective.
0:24:46 > 0:24:49But it does give you that sense of other-worldliness.
0:24:49 > 0:24:53If you're building a place that cultivates a sense of heaven
0:24:53 > 0:24:57and the world beyond, just that little glimpse does that.
0:24:57 > 0:24:59I wonder if that's accident or design.
0:24:59 > 0:25:01It's the kind of thing you can't tell from a model, isn't it?
0:25:01 > 0:25:03You need the effect of space.
0:25:03 > 0:25:07- I'm sure Mr Wren said he did it on purpose.- Do you think?- Oh yes.- Yeah.
0:25:07 > 0:25:11We must be about halfway now, Lucy, between top and bottom?
0:25:11 > 0:25:15It's hard to tell. Those chairs, those people still look pretty small.
0:25:15 > 0:25:17They do look tiny.
0:25:17 > 0:25:20Let's not focus on that. Let's look up.
0:25:20 > 0:25:23This level's the famous Whispering Gallery.
0:25:23 > 0:25:27If you walk out through one of those tiny doors
0:25:27 > 0:25:33and speak against the wall, then people around the perimeter can hear what you're saying.
0:25:33 > 0:25:37- (It also works in the middle. - Yeah, I'm definitely whispering.
0:25:37 > 0:25:40(Scientifically proven.)
0:25:40 > 0:25:43- Right, down we go, madam. - Let's head off-ski.
0:25:48 > 0:25:53- For a very brief time only, lap it up, Luce.- I know.
0:25:59 > 0:26:04Christopher Wren intended St Paul's to have a plain stone interior
0:26:04 > 0:26:09decorated with carvings in keeping with the classical style.
0:26:09 > 0:26:13But the Victorians added much more colourful and ornate decoration
0:26:13 > 0:26:16which can be seen in the eastern end of the cathedral.
0:26:16 > 0:26:19You really appreciate the architecture from this position
0:26:19 > 0:26:25because you get a bird's-eye view of the whole of the cathedral floor.
0:26:27 > 0:26:32You see Victorian mosaic work in the spandrels, between the arches.
0:26:32 > 0:26:37Quite painterly in style. And the bits of gold work,
0:26:37 > 0:26:41angled so that they catch the light. It's a very exotic, Eastern take.
0:26:41 > 0:26:45It's being able to see the vaults at the same time and the dome.
0:26:45 > 0:26:47You seem to be in close proximity to everything.
0:26:47 > 0:26:50Yeah, you've sort of got a perspective on the whole building.
0:26:58 > 0:27:03Wren lived just about long enough to see his monument finished. The sculpture wasn't all completed.
0:27:03 > 0:27:08It was 1723 when he died. He was aged 91, a grand man who contributed
0:27:08 > 0:27:12so much to science as well as to architecture.
0:27:12 > 0:27:18He was really the person who brought in the Georgian age and England would never look the same again.
0:27:18 > 0:27:21He was buried here at St Paul's,
0:27:21 > 0:27:23right beneath our feet.
0:27:23 > 0:27:25And you can read that inscription.
0:27:25 > 0:27:29"Christopher Wren.
0:27:29 > 0:27:33"Lector, si monumentum requiris circumspice."
0:27:33 > 0:27:36"Reader, if it's a monument you want, look around you."
0:27:36 > 0:27:38And this is the place to look from.
0:27:47 > 0:27:50- That was... - It was extraordinary, wasn't it?
0:27:50 > 0:27:53Yeah. I'm almost speechless.
0:27:53 > 0:27:55I'm really chuffed with that.
0:27:55 > 0:27:58I wish I could commit that to memory for all time.
0:27:59 > 0:28:03A true one-off experience. You know, it's a familiar landmark.
0:28:03 > 0:28:09You think you know St Paul's because you've seen the dome from the outside. It's that iconic shape.
0:28:09 > 0:28:12But the irony is there's so much more to it.
0:28:29 > 0:28:32Subtitles by Red Bee Media Ltd
0:28:32 > 0:28:36Email subtitling@bbc.co.uk