Barney at the Bedlam Dig Blue Peter Bite

This is Blue Peter, but mini.

Expect epic adventures, makes, bakes, badges,

pets, presenters and your post.

We've only got five minutes, so get ready for your Blue Peter adventure.

I'm standing on one of the biggest construction sites in Europe.

Crossrail is running new train tunnels across the city

which in itself is pretty impressive,

but there is so much more to this story.

And to find out, I've got to go to down there.

Crossrail is a brand-new underground train line

being built beneath the streets of central London.

Look at this, look at the size of the place!

Costing over £14 billion to construct, this super-sized project

will tunnel 26 miles across the city at depths of up to 40 metres.

Now, if you're going to dig this deep and this far in a city this old,

you're going to find some pretty incredible stuff.

I don't know, like an ancient burial site, for example.

Lying directly in the path of the tunnels is a huge graveyard

near Liverpool Street station, known as the Bedlam Burial Ground.

This is the final resting place for thousands of Londoners, dating back

to the 16th century, and includes patients from the Bedlam Hospital.

So far over 3,000 skeletons have been found, turning this

building site into one of the UK's biggest archaeological digs.

What is archaeology? It's much more than just digging stuff up, isn't it?

Yeah, archaeology is the study of the entire history of humankind,

so from the very earliest days, when people were making

the first stone tools,

right up to a burial ground like this.

Can you talk me through HOW you dig up a skeleton? What's the process?

Initially all the modern soils can come off with a machine,

but once we get down to that level of the first burial

it's about taking over with very careful hand tools,

trowels and brushes,

to carefully pull the soil back away from every individual skeleton.

Well, obviously this is Blue Peter - I've got my gloves on

and I'd love to help out if I can.

Well, let's go and have a look at one of the burials we're excavating

at the back of the site there, and perhaps you can take

some of the soil away and put it in a barrow for us.

-If it's taking soil away, I'm your man. Let's do it.

-Let's do it.

What Jay didn't tell me was just how much earth needs clearing.

In total, over three million tonnes of the stuff is being removed

to make room for the new tunnels.

Yeah, it's a dirty job but someone's got to do it.

There we go.

One down, about four million to go.

Of the 3,000 skeletons the team have already uncovered,

many were victims of the infamous Plague, or Black Death, that swept

through London and in 1665 claimed the lives of around 100,000 people.

This is one of the individual graves that we're excavating.

Alexa's just cleaning off the final part of the top of the coffin.

And what is really exciting about it is we've got initials

appearing on top of the coffin lid.

What you can see, probably make out, is an R there,

possibly an O, a C or a G -

it's been disturbed - and then a number there.

So this would have recorded the initials of the person

and the date they were buried.

What an amazing discovery!

So while the team continue their work, I went to find out what

happens to the remains once they've been excavated from the site.

First of all, the bones need to be carefully cleaned

and dried, by a team from the Museum of London, before they're sorted

and prepared for further examination.

How do you actually go from having trays which are just jumbled up

pieces of bones and skeleton to putting them all together

and telling a story?

Basically you lay the individual out bone by bone

in anatomical position.

It's really incredible what an expert like Don

can tell from studying these bones.

Well, we can tell they lived

until they were probably between 20 and 30 years of age.

We can look at the spine - that tells us that

they basically walked with a bent back.

You can tell that they had

a reasonably soft diet - the teeth aren't that worn.

So this person didn't eat a lot of sweets?

Cos the teeth are actually in very good condition.

We know that most of these individuals weren't really

that rich, and although sugar HAD been introduced in this period,

it was quite expensive.

So whilst the wealthy could tuck into plenty of sugar,

the poor didn't have quite so much access to it.

Well, if we move on to our next guy over here.

That looks like an impact or some kind of injury.

Something has hit the skull in this area

and caused the bone to be depressed.

It's a very serious injury

and would have required quite extreme force.

However, we can tell from

the smooth edges of the bone that

actually this individual survived.

-Wow.

-It shows that even with quite nasty injuries you could survive,

even in those days.

It's quite amazing how you can tell so much from so little, isn't it?

These are just some of the amazing discoveries being made by the team,

and they give so many clues about life in London hundreds of years ago.

When this dig is complete,

some of their finds will be displayed in the Museum of London

and the Natural History Museum for everyone to come and see.

Isn't it fascinating to think that something as new as a modern

railway station can unearth so much about our past?

It makes you wonder, doesn't it -

what other secrets are hidden underneath our feet?

Join in every Thursday on CBBC.