I'm Rory Stewart and I grew up wanting to be a hero and I'm still fascinated by the ideas of heroism.

In my new series, I'm taking in the long sweep of history from Achilles to Zelensky and asking, what is a hero?

Simply doing your job, being a decent human being.

A true hero is someone who just kind of shines by their own light,

and that light is to be recognised by others.

The Long History of Heroism with me, Rory Stewart.

Listen on BBC Sounds.

Thank you for downloading from the BBC.

For details of our complete range of podcasts and our terms of use,

go to BBCworldservice.com slash podcasts.

BBC.

2011 has been declared International Year of Chemistry, a chance for scientists and manufacturers

to get us all thinking again about one of the major disciplines transforming the modern world.

For those engaged every day in the topic, chemistry has brought us medicines, materials, fertilisers

and a thousand other benefits. For outsiders, medicines, materials, fertilisers, and a thousand other benefits.

For outsiders, though, sometimes the results has looked more like pollution and contamination of the planet.

But that could all change.

I'm Roland Piz, and in this edition of Discovery on the BBC World Service, I'll be looking

into one of the key themes of the International Year of Chemistry, Green Chemistry.

Green chemistry is not really a field of chemistry, it's more like a philosophy of chemistry,

a new way of thinking about chemistry.

Professor Philip Jessup has long been a keen advocate of green chemistry. When you're looking at pollution coming out of an industrial process, for example,

...