National Geographic: Ancient Asteroid Apocalypse: We all know the story of how an asteroid hit the earth to wipe out the dinosaurs and clear the way for mammals to become the planetís dominant life form. But what we donít know is what was it like on that day. What the after effects of this giant collision were and why some animals survived whilst almost everything else was wiped from the face of the earth. In short, what it would have been like to have been there the day the world changed forever and all in a single day? Well thanks to this superb documentary from National Geographic we can get one step closer to the answers with an hour-long investigation into the day the dinosaurs were wiped out.