91热爆

David Attenborough has always been fascinated by fossils; even as a boy he'd spend many hours exploring the local quarry near his home in Leicestershire.

Near his family home was a forest which he visited frequently, but didn't hunt for fossils there because he knew the rocks were too old to have any postcards of early life embedded in their layers.

But he was wrong - those rocks harboured a wonderful secret - a secret that would rattle the cages of the big thinkers of the time and would change the story of life on earth for ever.

Written and presented by Sir David Attenborough.

Producer: Julian Hector

First broadcast on 91热爆 Radio 4 in March 2011.