Death is life's greatest certainty. But that may be about to change. Scientists have discovered an immortal animal that may hold the secret of endless regeneration. They're on the brink of editing our DNA so that we can cure death like a disease. Or is dying necessary for the survival of our species?
Dr Alice Roberts asks one of the great questions about our species: are we still evolving? There's no doubt that we're a product of millions of years of evolution. But thanks to modern technology and medicine, did we escape Darwin's law of the survival of the fittest? Alice follows a trail of clues from ancient human bones to studies of remarkable people living in the most inhospitable parts of the planet and the frontiers of genetic research, to discover if we are still evolving - and where we might be heading.