Those white cliffs are a dense Cambrian limestone.

Here's a piece of 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.

I don't want him killed. I know he's going to love cliffs.

Now, at the base of the high cliffs there's this natural cave.

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.

BASE jumping is skydiving from fixed objects, like buildings, antennae, bridges and earth meaning mountains, cliffs.

This discovery changed everything about our sense of these cliffs and what to do with them.

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.

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.

Landscape ecology concerns itself with how the stream and the meadow and the forest and the cliffs make habitats for plants and animals.

This is all Forest Service land. If you go up on top of those cliffs, that's some of the Long Now land in those trees.

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.

And you can carry right on up through meadows and steepening forest to the high base of the cliffs at 10,500 feet, where there's a bit of a problem.

And as you come from the north, it is all masonry growing out of the sand cliffs as you come from the Himalayas and evoking the tradition of the fortress.

The terrain in Pitcairn is of rugged volcanic formation, with a rocky coastline and cliffs lining nearly the entire perimeter of the island, giving no easy access from the sea.

Start with borders. If you look on the left side of the cliffs here, that's national park. That's sacrosanct you can't do anything with that. To the right of it is national forest.

It's this beautiful world all of its own, surrounded by cliffs, and it's an easy hike to stroll up the canyon bottom, until you get to this barrier, and it actually presents a problem.

Bring me blocks of iron. So that, when he had leveled up between the two cliffs, he said, Blow. And having turned it into a fire, he said, Bring me tar to pour over it.

Bring me blocks of iron. So that, when he had leveled up between the two cliffs, he said, Blow. And having turned it into a fire, he said, Bring me tar to pour over it.

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.

Give me pieces of iron till, when he had levelled up (the gap) between the cliffs, he said Blow! till, when he had made it a fire, he said Bring me molten copper to pour thereon.

Give me pieces of iron till, when he had levelled up (the gap) between the cliffs, he said Blow! till, when he had made it a fire, he said Bring me molten copper to pour thereon.

Bring me ingots of iron' After he had leveled between the two cliffs, he said 'Blow' And when he made it a fire, he said 'Bring me molten copper so that I may pour over it'

Bring me ingots of iron' After he had leveled between the two cliffs, he said 'Blow' And when he made it a fire, he said 'Bring me molten copper so that I may pour over it'

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.

And the structures rise from the sand cliffs they're built in concrete and sandstones the roofs are stainless steel they are facing south and reflecting light towards the temple itself, pedestrians crisscross from one side to the other.

Now, I happened to be on the radio with Alexander when he got to this point at the base of the cliffs, and he said, quote, There's a hidden notch. I think I can get up a ways.

In this illuminating talk, Richard Pyle shows us thriving life on the cliffs of coral reefs and groundbreaking diving technologies he has pioneered to explore it. He and his team risk everything to reveal the secrets of undiscovered species.

Bring me ingots of iron!' Until, when he had made all level between the two cliffs, he said, 'Blow!' Until, when he had made it a fire, he said, 'Bring me, that I may pour molten brass on it.'

Bring me ingots of iron!' Until, when he had made all level between the two cliffs, he said, 'Blow!' Until, when he had made it a fire, he said, 'Bring me, that I may pour molten brass on it.'