London.
On the surface - it's a buzzing, modern metropolis.
But underneath lie secret, hidden worlds,
all but forgotten by the millions of people above.
This is the bit the general public don't usually see.
Digging down deep, we'll unearth some
of the most extraordinary stories
of London's subterranean history...
(Air raid siren and falling bombs)
..a world of ancient caves and preserved Roman ruins.
And we're now coming into the amphitheater itself.
We'll discover impenetrable vaults of treasure...
I have actually heard people gasp as they walk in for the first time.
..gruesome plague pits, and top secret bunkers.
The bunker was designed to be entirely self-sufficient.
For those in the know, there really is a darker side to this city.
This is the secret world underneath London.
This program like you
Modern London is built on layers of history.
All you have to do is dig down deep to discover:
secret hiding places used in World War II...
masterpieces of Victorian engineering...
remnants of the Industrial Revolution...
millions of medieval bones...
..even forgotten underground rivers.
The very first layer of the city was laid down as far back as 50 AD.
London was founded only six or seven years
after the Roman invasion of Britain.
It was founded on the River Thames.
This was a highway that connected
London and Britian to the continent.
A few clues to the original city can
still be found on the surface today...
like these remnants of Roman walls in the heart of London.
Other traces have survived which can
show us how powerful the city was.
But to see those, we need to go underground.
In 1987,
construction workers preparing the
foundation for the Guildhall Art Gallery
unexpectedly unearth a piece of London's past...
nearly 2,000 years old.
At first, architects have no idea what they've found.
Archaeologists are equally puzzled.
But when the full structure is exposed,
they realize the magnitude of the discovery.
This is London's long lost Roman amphitheater.
We're now 20 to 30 feet underground.
You can see the walls on either side.
And we're now coming into the amphitheater itself.
It is built for entertainment - Roman style.
Events are held within its huge circular arena,
200 feet across.
This wasn't the biggest amphitheater in the Roman Empire.
It held 5-6,000 people.
But that was a quarter of the population of London at the time.
That's the modern equivalent of the entire central London population
leaving the streets for one event.
Roman society was very brutal, you can't get away from that.
In the army, you were brutalized and you in turn were brutal.
It was part of everyday society.
But at the same time, you can relate to it.
The celebrities of the day are the gladiators.
Posters will have gone around, all round
the city up to two weeks beforehand.
The night before the shows themselves, there was a huge public meal,
at which the audience could come and
watch the gladiators taking part,
so they could see what was going to happen
and work out who they wanted to bet on.
For those about to come into the arena,
it was unimaginable how horrible that must have been.
Among the ruins,
archaeologists find a tiny clue that gives a stark insight
into the fears of the fighters:
a figurine of Minerva, the Goddess of defense.
This may well have been a lucky charm
carried by a gladiator as he entered into deadly combat.
But you still got people who wanted to do it.
It was a way to make a name for yourself.
Gladiators fight and die in this
amphitheater for more than 250 years.
When the Roman Empire falls,
the building is simply lost in time.
More than 1,000 years later,
everyone in London is at risk from a
killer far harder to avoid than a sword.
The city isn't just built on ruins.
It's also built on bones.
Over the centuries, millions of people have lived and died here.
Most visitors to the Museum of London
are completely unaware that thousands of those bones
are preserved right under their feet.
This is the most phenomenal collection of human remains
that have been excavated over many years
and reveal the history of London through the people.
Each of these boxes contains the bones of one person.
The numbers are astonishing -
there are close to 20,000 of them.
One collection that we have that's of particular significance
is an episode of a really terrifying time in London's history.
That time is 1348...
when the city is ravaged by a horrific plague...
the Black Death.
No one is safe.
This skeleton is a male
that was excavated from the East Smithfield Catastrophe Cemetery
and is a plague victim.
When you look at his skeleton,
he looks like a very nice robust, healthy individual.
But the plague killed him very quickly.
By the 14th century,
the center of London is an overcrowded jumble of streets.
Conditions are probably not as sanitary as we would hope today.
So you've got lots of dirt and filth accumulating on the streets.
The city is a melting pot for disease.
When the plague strikes, its effects are terrifying.
If you were, unfortunately, to be affected by the plague,
you would probably start off by developing a fever
because your body is trying to fight and cope with it.
And then a later stage would be that it affects the lymph nodes,
and you start to get the swellings,
so you might get those in the neck, the armpit or the groin.
They become these swellings that we know as buboes.
That's actually then poisoning your whole system.
You're eventually going to get septicemia, blood poisoning.
For most people, ultimately, it would be death.
As a disease process, it was very quick and
affecting lots of people all in one time.
As the death toll rises, local
cemeteries rapidly fill to overflowing.
Bodies are simply left to rot in the streets.
Authorities have to act fast.
The solution is the creation of London's plague pits.
Thousands of corpses are laid carefully side by side.
They were being placed there in a very neat way
and they were trying to follow that Christian burial process
so they weren't just being flung in haphazardly.
Over six centuries later, in 1986,
archeologists excavate the East Smithfields plague pit,
where 2,500 victims are buried.
Scattered between the countless rows of men and women
are the bodies of children, mercilessly
cut down by the unstoppable plague.
It didn't care really whether you were young or old,
if you were rich or poor.
It's a snapshot of all people of all different ages
being affected by one disease process.
Scientists are finally able to investigate this long-hiddte.
The way we were able to find out the cause of his death
was actually by taking a tooth
and then being able to sample that
to find the causative agent of the plague, the black death.
The results confirm what scientists long suspected.
The culprit is a deadly bacterium that is still alive today -
Yersinia pestis.
Recent outbreaks have been reported in Africa, Asia,
even in North America.
The bacteria live in fleas that are carried by rats.
Just one flea bite can infect a human.
Without these bones, we would never have known for certain
that a tiny microbe was the cause of such widespread destruction.
By 1350, when the plague finally loosens its grip on the country,
over 40 per cent of London's population -
30,000 people - have died.
300 years later, in 1666,
the city faces a very different kind of disaster.
The Great Fire of London tears through the city.
80 per cent of it is burned to ashes.
When the last embers die out, rebuilding is a priority.
Amazingly, the key to the city's future
is found deep underneath the sleepy London suburb of Chislehurst.
In this otherwise unremarkable place,
is a doorwaytoth world.
A dark and mysterious world.
It's a labyrinthine sprawl of endless, disorienting, tunnels.
Reaching down 230 feet below the surface,
there are more than 22 miles of them.
These are the Chislehurst Caves.
And for 17th-century architects, they
are a Mecca for one essential resource.
There we have it - chalk. Seaford chalk.
Chislehurst Cave is made up of nothing but chalk.
Bricks and mortar are the new construction standard for London,
and chalk is a vital ingredient.
You can't have roads, you can't have walls without chalk.
After the Great Fire of London,
chalk would have been removed from any available chalk mines,
Chislehurst Caves being the largest in the country.
The deeper you go down, the harder it is.
Hard chalk is notoriously brittle.
And that creates problems for miners.
Hit it in the wrong spot,
if there's a pocket behind it,
you'll end up with ten tons of chalk coming down right on top of you.
For miners, cave-ins are an ever present threat.
But London's building demands must be met.
So much chalk is extracted over the years
that the caves turn into a giant maze.
It's very easy to get lost down here.
If you were to turn all the lights off, it's pitch black.
In fact, I can show you.
Though there is a total absence of light,
the layout of the caves means that sounds are hugely exaggerated.
(Sound reverberates)
(Deep rumbling echo)
With 22 miles of tunnel,
who knows what might be listening?
Far into the mines, there is a natural pool.
Legend has it that a grim discovery was made here decades ago.
They found something at the bottom,
and that something happened to be the skeletal remains of a woman.
Disturbing her bones is thought to have woken her spirit.
A challenge is set for anyone who dares
to spend the night alone in the caves.
So come 1985,
Dave Duker and Chris Perry Manning
decided that they'd do the challenge for a charity.
- See you in the morning. - Yeah, I hope you will.
The rules of the challenge say they must sleep separately.
Thanks, mate.
So Dave was actually placed right here behind me,
Chris slept at the far end of the passage.
Deep in the darkness, the hours pass slowly.
- (Panicked shouting) - Chris!
Chris! Chris!
Chris!
Dave discovers Chris unconscious.
He's rushed to hospital where doctors
find his shoulder dislocated and broken.
Chris remembers nothing.
Because of that night, and him not knowing
anything about it even to this day,
the challenge was called off.
It's never happened again, and it never will.
The ghostly Chislehurst Caves were excavated
using primitive mining techniques.
But 200 years later,
the technical prowess of the Victorians
takes underground tunneling to a whole new level.
This is the Thames Tunnel.
This is the first tunnel under a river anywhere in the world
being used by the oldest underground system in the world.
During the 19th century,
the Thames is one of the busiest rivers in the world.
The port of London receives thousands of ships daily.
They needed to get stuff across the river as well as up and down it.
London bridge is the only way to cross.
It's constantly gridlocked.
They said, in these days, it took
longer to get stuff across the Thames
than it took to get stuff across the Atlantic.
Building another bridge would block ships' access to the docks.
Luckily, there is one man clever enough to solve the problem.
Marc Isambard Brunel is a Frenchman living in America.
His technical skill has raised him up to the office
of Chief Engineer of New York.
He was a prolific engineer.
He designed the defenses on Staten Island.
He made plans for the first canal in North America,
from Lake Champlain up to the River Hudson,
which is a bit of real prospecting.
In 1799, he arrives in England to face his greatest challenge:
the world's first tunnel under a river.
The big challenge for anyone building a tunnel under this river
is the composition of the soil.
South of the river and under the river,
it's sand and gravel and sludge.
It's the worst possible material to dig through.
The ever present danger was cave in and collapse.
Brunel's plan is audacious.
He designs what many believe is one of the
finest pieces of Victorian engineering.
This is Brunel's brilliant idea.
How do you dig tunnels under rivers through soft earth?
It's a cage.
Brunel plans to prop the cage up against the tunnel face,
giving support to the soft tunnel walls
while allowing workers to excavate earth from under the river bed.
As earth is removed,
the cage would be edged forwards on screw jacks.
As they push the cages forwards,
bricklayers working behind them build the walls of the tunnel.
In this painstaking manner,
the tunnel could be built, inch by inch.
But before they can start building it,
they have to get down below the river bed.
This is the bit the general public don't usually see.
This is the secret entrance to the underground chamber
which has been opened up again for the first time in 150 years.
In another of Brunel's engineering firsts,
he begins by building this 50-foot deep,
1,000-ton brick cylinder above ground.
Then, instead of lowering it into a pre-dug hole,
Brunel relies on the laws of gravity.
It's like a huge pastry-cutter.
Because it's sunk under its own weight into the soft earth.
This is the world's first caisson.
It's been done all over the world ever since.
If Brunel did nothing else,
this would have been significant enough.
Marc Brunel's son, Isambard, is enlisted to oversee the project.
With the cage in place, tunneling begins in 1825.
The challenge proves far greater than
the Brunels could ever have imagined.
The men working here worked in the most appalling conditions.
The tunnel is 14 feet below the river.
There are constant leaks.
They were showered in the small cages by Thames water.
In 1825, the Thames is the biggest open sewer in the world.
They're not just dodging sewage, they're dodging flames.
Because the methane in the tunnel is ignited
by the oil lamps that help them see to work.
They only work two-hour shifts, however.
After two hours, they collapse.
(Coughing)
And they're carried out and replaced by men who are still breathing.
This is the worst job in the world.
Before long, the inevitable happens.
In January, 1828, six men drowned in here.
The river broke into the workings,
filled the tunnel and filled this chamber.
Two men reached the staircase
but the force of the water was so great
it tore them off the stairs and sucked them down
below where we're standing,
inne and to their deaths.
The tragedy does not deter the Brunels.
Isambard devises an ingenious way to
restore public faith in the project.
In November, 1827, the great and the good
dined beneath the River Thames,
off silver platter and from crystal glass.
If it's safe enough to have a dinner party down there,
it's safe enough for potential investors
to take up a second subscription of shares
and give the Brunels the money to resume the work.
God save the King!
This is very classy fundraising.
In 1843, 18 years after building began,
the tunnel is complete.
It's a huge success.
Billed as the eighth wonder of the world,
50,000 people use the tunnel on the first day.
The Brunels went through hell and high water to build this tunnel.
It was a project that Brunel thought would
be finished in three years, that took 18.
Men grew old and died building this tunnel.
A lesser person would have given up.
This is not only a testament to Brunel's engineering skills,
it's a testament to his stubborn, gritty determination.
This is an act of will as well as an act of engineering.
Marc Brunel's incredible tunnel under the Thames
is used as a pedestrian crossing until 1865,
when it becomes part of London's railway network.
But it's by no means the last great challenge of the Victorian age.
In the old industrial district of Clerkenwell,
there is a tiny clue to one of London's biggest secrets.
In the busy city streets,
this simple drain cover is easy to miss.
If you listen closely, you can hear a rushing sound,
and that rushing sound is the sound of water.
And the water here offers a clue to London's past
and what lies underneath our streets.
There's only way to solve this mystery.
We need to go underground...
..20 feet down, below the busy streets...
..to the source of the rushing sound.
This is one of London's great lost rivers - the Fleet.
Okay, Tom, we're in the Fleet.
We're just going to go this way, upstream, follow me.
This river hasn't always been buried underground.
During the 19th century, it's a major highway for transporting goods.
The River Fleet used to be an important
part of the way London worked.
Boats would come up here,
barges would unload on this river.
They would unload things like the stones
that built the old St Paul's Cathedral,
they'd unload coal, they'd unload cheese,
they'd unload produce for the city.
The Fleet gives clear access from the north of London
all the way to the Thames.
But the city's use of the river takes its toll.
Slaughterhouses and tanneries along its route
are continually throwing their waste into the water, unchecked.
The River Fleet was notoriously polluted.
It was aedibly filthy river -
all of London's sewage, its waste was coming down here.
Even bodies were said to float down the Fleet every day.
The only way to make the river safe is to entomb it underground.
By 1870, it is completely covered over.
There's only a skin of brick and road surface
between us and hoards of people going about their everyday business,
doing the things that everyone does in the city.
And the Fleet is far from being London's only buried waterway.
The rivers that are out there have amazing evocative names.
They're called things like the Effra,
the Neckinger, the Falcon, the Ching,
the Moselle, the Mutton Brook.
But in most cases, they've been completely or partly lost
over the last 150 years.
And to find them, you have to go underground
and look inside the tunnels where they still flow.
As the great River Fleet is hidden away,
yet another piece of Victorian engineering
opens up a brand new world under London.
Commonly known as the tube,
the London Underground is the lifeblood of the capital,
transporting over a billion people every year.
It all starts with just one line - the Metropolitan.
During the 19th century,
railways bring nearly 30,000 workers
into London's stations every day.
But what's badly needed is a way to transport them quickly
into the very heart of the city.
One man started to come up with the idea
of actually putting the railway in a trench beneath the city streets.
Charles Pearson, a London lawyer,
is at first ridiculed for his proposal.
Pearson struggled for many years to convince people
of not only the need for the Metropolitan Railway
but then to give him the parliamentary power and finance to build it.
This was, after all, a private railway.
To the dismay of many,
his plans are finally granted in 1854,
as the only hope to ease congestion.
Building the world's first underground railway causes chaos.
The construction technique is called cut and cover.
The busy streets are blocked off and
trenches dug by armies of workers,
bringing the city to a standstill.
Train tracks are laid and the trenches covered over,
enclosing the railway below.
Slum properties in the way of the new line are ruthlessly demolished.
12,000 people are made homeless.
Wealthy residents are horrified by the
resulting unsightly gaps in streets,
so designers come up with some architectural trickery.
This seemingly normal town house is actually a facade
built to hide the gap and the railway behind.
In January, 1863, in spite of people who said it couldn't be done,
the Metropolitan Railway opens for business.
(Train's whistle)
It is powered by steam engines which fill the tunnels with smoke.
There were always issues about the atmosphere in the underground
being smoky, steamy, sulfurous...
Even on the opening week of service,
a couple of railway men had to be
taken to hospital with asphyxiation.
By the late 19th century,
580 trains a day are using the original section.
That's a steam engine every two or three minutes,
so you can imagine then it would've been pretty thick.
Despite the choking conditions,
people flock to the underground.
The Metropolitan Railway was really
a great success from the very start,
exceeding expectations in terms of the numbers of passengers.
Of course, it did important jobs.
It moved people from railway termini
such as here at Paddington into the city,
and it helped people move round London,
instead of using the congested
streets above ground.
By the early 20th century, several more lines are built.
This rapid growth makes navigating the tube very difficult -
and the Underground map has become a
complicated jumble of lines and stations.
Harry Beck, an engineering draftsman, has a genius idea.
Instead of being geographically accurate,
he takes inspiration from an electrical circuit drawing.
The map is laid out in simple, direct lines.
Using Beck's system, passengers only need to know three things:
the start point of their journey...
..where they have to change lines...
and their destination.
His design is so ground-breaking
that it becomes as famous as the city itself.
It just blew away all the other maps that
had ever been designed. It worked better.
Part of that pride about being a Londoner
is you know your way round the city
without actually having to look at the map
because it's just so well imprinted in your brain.
London relies on its underground to keep the city moving.
But there was a time when it was needed for much more.
In the heart of London sits one of the city's disused stations...
..Aldwych.
Opened in 1907 as a single station offshoot of the Piccadilly Line,
it was never particularly busy.
When the elevators broke down,
the cost to repair them was too great to justify.
The station is abandoned in 1994.
(Air-raid siren blares)
However, back in 1940,
this place plays a hugely important role for Londoners.
During the Blitz, the horrific Nazi bombing campaign of World War II,
Aldwych becomes one of London's great public air-raid shelters.
The tube station, of course, afforded the best and safest place
so people felt quite easy at leaving their home,
even if this was a very strange environment.
Each night, anxious Londoners descend 90 feet down to the platforms.
Every attempt is made to keep people's spirits up.
Singing and games are a regular pastime.
Christmas is celebrated wholeheartedly
There is even a refreshment special, a train that
runs selling cakes, pies, and of course tea.
As the last regular service passes through,
stations take on a very different atmosphere.
At that point, the station become a lot calmer and quieter.
That's when people really started to bed down for the night.
(Air-raid siren wails)
Every inch of the platform is used.
Makeshift hammocks are hung across the tracks.
(Bombs falling above)
But there's no escaping the horror of what is going on above.
Even deep underground, people can hear the bomb strikes.
Down here in the deep tube tunnel overnight,
you weren't certain what you were going back up to in the morning.
The landscape of London changed overnight.
You didn't know if your home was still going to be there.
So I think there was a great degree of tension.
(Bombs falling)
Terrified by the endless pounding of bombs,
no one pays attention to a door at the end of the platform.
On the other side is one of London's deepest secrets...
..a hidden tunnel.
It's the perfect place to hide something precious.
This area of the track that had been abandoned in 1915,
was used during the Second World War
for storage of famous artifacts from the British Museum.
Most valuable of all are the 2,500-year-old Parthenon Sculptures.
These priceless pieces are among the finest example
of Greek classical art in the world.
War meant that they couldn't continue here safely,
so they were dismantled,
and gradually were all transferred to the
deepest, ne est underground station -
the Aldwych Tube.
Moving 100 tons of ancient marble deep below ground
is a precarious operation.
It's very tricky because the condition
of the sculptures after 2,000-plus years
was already very volatile.
It was a real logistical feat, taking
very precious and delicate sculptures
and bringing them here to a safe resting
place deep under central London.
The sculptures remain underground for ten years -
untouched by the war above.
With German bombs laying waste to the city,
the British Prime Minister is holed up in Westminster.
Just 100 yards from his home in Downing Street,
Churchill has a top-secret bunker, 12 feet below ground.
These Churchill War Rooms
were designed as an emergency working refuge for the War Cabinet.
They have sat here, frozen in
time, since the end of WWII.
In the 1970s, they were entrusted to the care of the Imperial War Museum.
This is really what we found, when we came here in the late '70s.
These are the chairs, the tables, the maps...
The blotters, in a sense, are not original,
because they would burn the blotters at the end of each meeting,
in case you'd left an impression of something secret on them.
These are the blotters for the next meeting that never happened,
because there was no need to have it.
The Prime Minister's decision to
remain in the city is typically bold.
His enemies never guess that Churchill is so close to home.
If you were Hitler, you wouldn't think, 'Where's Churchill?
I don't know - 12 feet underground in a storage basement
100 yards from his house?'
No way.
You would think like Hitler, like Mussolini, like Stalin,
180 feet below ground under concrete and ballast.
Our man? A converted basement 12 feet below ground.
The site is a safely guarded secret.
Only staff and top government officials even know it exists.
Churchill would sit in this seat here,
and he would have on his left the leader of the opposition,
since it was a coalition.
And on his right, where I'm sitting, you
would have the War Cabinet Minister.
He's got the chiefs of staff opposite him,
who never seem to be going fast enough or
doing things the way he wants them done.
He's only down here because they're bombing the hell out of his city.
So it would've been fairly scary, I think.
Whatever you think of the apparent fortifications of this place,
it was very prone.
Any bombs landing nearby could easily
have come through here at any point.
With the fate of Europe hanging in the balance,
the tension is unrelenting.
It's a very cramped room, so you'd feel fairly claustrophobic.
And the intensity Churchill felt
is really exemplified by what you
see here when you look at the chair.
Here we have a dent in the chair where
he hammered it with his signet ring
that he wore on that finger.
On the other side, an even deeper dent,
incredibly made by his fingernails.
Churchill keeps an eagle eye on every aspect of the war -
up-to-date information is of vital importance.
This is where they would track all
military operations throughout the war.
Round this table, you'd have one each
of the Army, Navy and Air Force, 24/7.
These guys would've had it all absolutely
as Churchill would've wanted it.
This was his principle map room, this is where he would come in
and expect to see at a glance what was going on in the war.
(Telephones ringing)
Brightly-colored telephones sit waiting,
their ringers silent since 1945.
Maps line every wall.
Thousands of tiny holes detail the
precision with which the war is followed.
The most disturbing map in the room is this convey map.
Each one of those pin pricks basically represents a whole convoy.
Each convoy could be as much as 40 ships,
each convoy could be tens of thousands of men.
German U-boats prowl the Atlantic,
picking off Allied ships at will.
Your life expectancy on one of those ships was very low.
It's estimated that 35,000 mariners died at sea.
And that piece of water is one absolutely massive graveyard.
So great is the need for confidentiality during the war,
that some places are hidden from even the highest officials.
Cunningly disguised as a restroom,
this is a secret within a secret.
This is the original hotline,
the direct connection between the American
President and British Prime Minister.
The discussions held in this room are pivotal to winning the war -
but the Allied leaders still like to
assert their authority with one another.
Churchill wouldn't come on the line until Roosevelt was on the line,
Roosevelt wouldn't come on the line
until Churchill was on the line.
Churchill uses this bunker in central
London throughout the war years.
But this is not his only underground hiding place.
In the quiet suburb of Dollis Hill
hides one of London's
greatest World War II secrets.
Even today, the exact location of its entrance cannot be revealed.
Rusting equipment gives a clue to this place's original function.
This piece of old bent metal -
that's an original telephone exchange from 1939.
On the very back here, we've got all the wiring points.
ZDHDS teleprinter circuits.
Here we see a wiring frame.
And here we have the most important one of them all,
with a label marked CWR - Cabinet War Room,
the link to the main Cabinet War Rooms
down at Storey's Gate in London.
This site, codenamed Paddock,
is the Prime Minister's classified backup bunker.
If the main War Rooms are destroyed,
the free world is at grave risk.
Paddock is designed to rehouse Churchill'Cabinet
should the Luftwaffe land that grievous blow.
They started digging the hole in 1938 to build this bunker.
It took them just over 13 months.
It cost £250,000 - in those days, that's an enormous amount of money!
The bunker is covered with a giant concrete slab, five feet thick,
laid over with 17,000 tons of gravel.
The massive protection ensures that even
a direct hit from a German 500lb bomb
would not penetrate to the vital rooms 40 feet below the surface.
And it is built in complete secrecy.
Essentially what we've got is a two-story
office block sunk under the ground,
rooms off on either side, now totally dilapidated.
Paddock is state-of-the-art, fitted with the latest technology.
The bunker was designed to be entirely self-sufficient.
Had the worst come to the worst and the
power had been lost from the grid,
you just started the generator, had electricity in a few seconds.
Staffed 24/7, the bunker is ready to
spring into action at the drop of a hat...
..or a bomb.
It is laid out, of course, to the Prime Minister's specifications.
And it was in here, through this double
door arrangement, there was the map room.
There would've been maps across the wall
and a huge table here in the middle.
Here we have the three rooms for the armed forces -
one for the Army, one for the Admiralty
and a final one for the Air Force.
Each has their own unit, allowing them
to follow progress in the map room.
Privacy is vital in case there is a mole in the building.
And this is the most important room in the bunker, I suppose.
This is the Cabinet War Room.
Whilst Churchill held a War Cabinet meeting here in October, 1940,
he absolutely hated it.
'A most dismal place,' as he described it in his memoirs.
By the end of the war, cabinet has met here only twice.
With the cost of construction,
that's the modern equivalent of more than $20 million a meeting.
1945 signals the end for Nazi Germany,
and the need for the Allied secret bunkers.
Locked away from the world, Paddock falls into complete decay.
All these years on, this bunker is still here.
And it pays testament to the engineers that built it.
And it's such an important part of British history.
This is the secret world underneath London.
Despite the damage caused to the city during the war,
the Allied victory ushers in a time of great prosperity in London.
In 1953,
one of the most valuable properties in London is established -
a basement worth more than the most exclusive penthouse.
Onceide, it's a spectacular sight.
These are the London Silver Vaults.
Stashed away in these impenetrable vaults
is the largest collection of retail silver on earth.
In room after room, as far as the eye can see,
glittering, sparkling silver.
I have actually heard people gasp
as they walk in for the first time
and walk down the corridors and see the truly...
enormous expanse of silverware.
It is an amazing place.
The silver vaults were originally used for storage.
Then customers of ours began to come down here
and this whole place sort of evolved
into this huge shopping area for silverware.
This fully-subterranean site occupies
roughly the same size as a soccer field.
The collection's variety is truly astounding.
If you're looking for a silver item,
chances are you will find it here...
no matter how unusual.
The most outlandish thing I've ever seen...
was a solid silver four-poster bed and I couldn't believe my eyes.
The vaults are so remarkable that
they attract all sorts of clientele...
including the world of show business.
From the stars of yesterday...
Rock Hudson is a famous one.
The Dallas stars - they're still remembered,
Larry Hagman came down.
..to the prop buyers for popular television dramas of today.
Downton Abbey - they decided to actually buy silver from ourselves
rather than rent it.
Everything you see on the Downton set came from here,
came from us, our family.
For one virtuoso performer, this place was one giant candy store.
A particular purchase, from the Langford family vault,
was to become his signature piece.
Liberace came down and bought silver candelabra.
Every visit to London, he would come back
and visit Mrs. Langford and send her Christmas cards.
The flamboyant pianist was naturally charmed by the silver vaults.
Its location certainly makes it
one of London's most unusual shopping destinations.
The fact that the London Silver Vaults are two floors underground,
is quite an unusual and quirky idea.
I actually love it, this is more like a hobby for me.
And the fact that I'm earning money while
doing my hobby - it's a great experience.
20 years after the vaults were founded,
London's underground is excavated once again.
This time it's to store a very different collection of treasures.
In 1973, the British Library is established
as one of the largest libraries in the world.
Within its care are the private collections of King George III
and two of the four existing copies of the Magna Carta.
Hidden out of sight is the Library's full collection
of over 150 million items.
The visitors may be unaware they're
sitting on top of a giant book depository.
The collections are stored in five huge subterranean floors
extending over 80 feet underground.
We're in Basement 3 at the moment and it's about 60 foot deep.
In certain spots, you can actually hear the underground passing you.
I think the Circle Line is about six meters away at some point.
These basements are a book lover's idea of heaven.
If a person could read five books a day,
it would take 80,000 years to finish the collection.
KELVIN: The books are given a catalogue identification,
a unique alpha-numeric sequence where they're held on the shelf.
We then make those available to our customers,
be it readers in the reading room or external customers.
On an average, we're doing about 3,000
requests a day retrieving those books.
The operation is pretty massive.
When a reader wants a book, they can
get access to the collection online.
You go onto the online catalogue, find the item that you want,
submit the order for the date you actually want it.
That then generates an order in the
storage area where the book belongs.
The staff respond to that order by
going to get the book off the shelf.
Finding the right book can involve a lot of walking.
There are nearly 400 miles of shelves,
with seven more miles added every year.
If a book's put back in the wrong place,
it can take an incredibly long amount of time to find it.
When the correct book is found,
the last step is poetry in motion.
This is the mechanical book handling system
where we actually send the books up to the reading room.
The book's put in a box encrypted with the address it needs to go to.
It enables us to send books to the
reading rooms efficiently and quickly.
A book's journey from the storage basements
80 feet below takes five minutes.
If you are overseas, you can order a book to arrive
in a reading room in four, five, six weeks' time
and time your visit to coincide with
that book being available for you.
Another happy customer.
As the densely-packed capital city continues to grow and develop,
the world underneath it becomes more important than ever before.
For one of London's most established institutions,
the underground is absolutely vital for the future.
As the first national public museum in the world,
the British Museum now attracts over six million people every year.
They come to marvel at the wonders of human civilization.
But not all of the museum's items are on display.
Packed into storage areas below the museum
are over 200,000 artifacts from every corner of the globe.
As the collection is constantly growing,
so too must the museum.
In 2010, construction company Mace begins work
on the largest site development
in the museum's 260-year history.
To maximize the potential of this relatively small piece of land,
a radical plan is put in place.
The museum was running out of space to go sideways.
So going down was really the only option.
Work begins on building four new floors underground.
That means digging down to 120 feet.
The key challenge in going down into a deep basement
is obviously getting the spoil away.
We had to take out 4,369 lorries' worth.
That's the equivalent of removing 15
Olympic-sized swimming pools of mud.
Digging out and construction has to be done with the utmost care.
Many buildings surrounding the museum are more than 300 years old.
There are important buildings,
Georgian terraced houses that back onto the site.
They come within 15 meters of the building
and even closer in some parts of the excavation.
And in places, the original walls of the
museum itself are agonizingly close.
On the other side of them are some of the world's greatest treasures.
Many of the objects are very fragile.
We had to ensure that the methods of work
weren't creating large amounts of vibration
that were then going to put the objects at risk.
We basically monitored daily the elevations of the existing buildings
to alert us if there's any movement in them.
Their vigilance is paying off.
And most visitors to the museum are
completely unaware anything is being built.
We've been on site for three years
and to close the museum for that length of time
would've been pretty damaging for the museum.
And in fact, we haven't had to close any of the galleries.
Building down under London's surface,
will bring a new lease of life to the British Museum.
As soon as you walk through the gate
and start to walk round the building,
you suddenly realize just how big a site this is.
The new levels of extra research, exhibition and storage space
will be the foundation for the museum's next 260 years.
It's not often you get the chance to build something
for one of the oldest museums in the world.
We're leaving a legacy here that will be here for generations.
London has many well-kept secrets.
We're adding another one here by building this underground.
This ambitious construction project
is not just the next chapter in the museum's story.
It's also the newest of hundreds of underground layers
that make up the 2,000 years of this rich and vibrant city.
Over that time, London has been shaped by innovations...
..victories...
..and tragedies.
And each has left its own secret trace,
hidden deep underground.
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