Here's a piece of limestone.

After the limestone rocks, what?

Those white cliffs are a dense Cambrian limestone.

And it's just limestone, nothing really special about it.

Would it give this block of limestone new properties?

The core comes up as these cylindrical tubes of limestone.

And it's different than this limestone, you can see that.

And that's not snow that's what the white limestone looks like.

Now a block of limestone, in itself, isn't particularly that interesting.

We don't just want limestone dumped everywhere in all the pretty canals.

On the trail we took just before we reached the limestone rocks.

I headed up hill just past the big limestone rocks we saw that Sunday.

So it would all be built in stone, in French limestone, except for this metal piece.

And Lost City was characterized by these incredible limestone formations and upside down pools. Look at that.

And so here the protocells are depositing their limestone very specifically, around the foundations of Venice, effectively petrifying it.

But gradually, as the buildings are repaired, we will see the accretion of a limestone reef beneath the city.

But imagine what the properties of this limestone block might be if the surfaces were actually in conversation with the atmosphere.

Ray It was Crease Limestone, and that was produced by sea creatures 350 million years ago in a nice, warm, sunny atmosphere.

The Kalahari Desert in the east and north is characterised by thick layers of the terrestrial land and limestone and scarcity rainfall.

And if you look even closer, you'll see, in that limestone, there are little shells and little skeletons that are piled upon each other.

This is our protocell technology, effectively making a shell, like its limestone forefathers, and depositing it in a very complex environment, against natural materials.

And architect Christian Kerrigan has come up with a series of designs that show us how it may be possible to actually grow a limestone reef underneath the city.

I love how they were able to preserve most in everything that makes you feel close to nature butterflies, man made forests, limestone caves and hey, even a huge python.

Qasr Al Hayr East The Umayyad limestone castle of Qasr Al Hayr East is in an isolated location in the middle of the Syrian Badia, 100 kilometres northeast of Palmyra.

The drill perforated the limestone to a depth of two metres without the use of lubricants or cooling fluids that might have contaminated the environment of the pit, and successfully collected six samples.

The drill perforated the limestone to a depth of two metres without the use of lubricants or cooling fluids that might have contaminated the environment of the pit, and successfully collected six samples.

You put the stick in the powder to take the sacred ashes well, they're not ashes, they're burnt limestone to empower the coca leaf, to change the pH of the mouth to facilitate the absorption of cocaine hydrochloride.

Nelson Mandela I take a little piece of limestone from Robben Island Prison, where he labored for 27 years, and came out with so little bitterness, he could lead his people from the horror of apartheid without a bloodbath.

If you walk around the city of Oxford, where we are today, and have a look at the brickwork, which I've enjoyed doing in the last couple of days, you'll actually see that a lot of it is made of limestone.

It is made through two basic routes from raw materials (iron ore, limestone and coke) by the blast furnace or basic oxygen furnace route (this method is known as the integrated route), or from scrap via the electric arc furnace (EAF) method.

But it goes a mile and a half in a straight line, due east into the range, into very interesting territory except that, as you'll see when we go inside in a minute, we were hoping for limestone but in there is just shale.

They were consistently dug as limestone quarries and by the 18th century, the caving in of some of these quarries posed safety threats, so the government ordered reinforcing of the existing quarries and dug new observation tunnels in order to monitor and map the whole place.