The long running, often bitter scientific debate over the origin of birds and the evolution of flight.

Dallas Campbell delves in to the Horizon archive to discover how our ideas about dinosaurs have changed over the past 40 years. From realising that lumbering swamp dwellers were really agile warm blooded killers, astonishing new finds, controversial theories and breakthrough technology have enabled scientists to rethink how they lived and solve the mystery of their disappearance. And they can even reveal whether dinosaurs might still be with us today.