From the moment of conception, every human embryo embarks on an incredible nine month journey of development. Now, cutting-edge technology makes it possible for National Geographics In the Womb to open a window into the hidden world of the fetus and explore each trimester in amazing new detail. Revolutionary imagery sheds light on the delicate, dark world of a fetus as never before.

Piers Gibbon travels to the Amazon to find out whether the macabre ritual of head shrinking, designed to stop a rivals evil spirit seeking revenge after death, is still practised

Asteroids and comets: Every year, millions of these stray bullets streak through the skies, and tons of small meteorites strike our planet! Some 65 million years ago, dinosaurs were wiped off the face of the earth - in what many believe was the aftermath of a massive cosmic collision. Could something like this happen again? Scientists believe that the impact of an asteroid only a mile wide would be globally catastrophic. Join extraordinary geologist Eugene Shoemaker and his wife Carolyn who have remapped the heavens with their discoveries of more than 30 comets and hundreds of asteroids. Now that we know whats out there, how can we defend ourselves?