Hello, I'm Justin Rowlatt.

Welcome to another chemistry special from Business Daily.

And today we turn our attentions to one of the most transformative chemical elements in the history of mankind.

To iron.

It's so important we've decided to split its story over three programs.

For millennia, it was nothing more than a handy but expensive craft material,

one that inspired this famous piece by Verdi.

Yet today, it is one of the basic substances with which our modern lives are built.

In this first programme, we explore the technological breakthroughs during the Industrial Revolution

that made all this possible.

And it began right here in the British Isles some three centuries ago.

Well, as you can probably hear, I've come out of the office, I'm in central London,

and I've got the privilege of coming to one of the finest buildings in the entire world.

I'm looking up at the wonderful structure of St. Paul's Cathedral with its magnificent dome.

But we've come here, bizarrely enough, to look at the railings. And I'm with Andrea Sala, Professor of Chemistry at University College London.

Why are we so interested in the railings? Because these are among the first iron structures. This is cast iron.

They were actually used for structural purposes. Before that, iron was really used in very small quantities.

And iron has ended up completely transforming the landscape around us. As we look at from here,

we're in the centre of London, one of the great financial centres of the world,

and we're surrounded by tower blocks, huge buildings, which presumably all have steel cores.

Yes, the entire development of the skyscraper is dependent on the unique properties that that element iron has,

particularly when we smelt it down and mix it with carbon.

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