Katrina was not a natural disaster but an engineering one, says the journalist and author. He chooses the best books on Hurricane Katrina, ranging from a novel to a geographical biography of New Orleans.

The historian explains how the power of technology has affected man’s relationship with the rest of nature, and tells us what determines why some civilisations succeed and others fail

One of the Natural History Museum’s experts in meteoritics, Dr Caroline Smith says the meteorites that land on earth predate our planet by about 150 million years and it’s not surprising that they land here

The respected author and veteran journalist gives illuminating interview on volcanic eruptions. Discusses wonderful literary works from authors including Jules Vernes, Edward Lytton and Paddy Leigh Fermor

Aid worker and consultant for Catholic Relief Services says working in tragic situations where victims have been traumatised is emotionally gruelling – but insists there are still opportunities to bring about change