Dallas Campbell delves in to the Horizon archive to discover how our ideas about dinosaurs have changed over the past 40 years.

The hunt for life within the long-dead bones of dinosaurs may sound like the stuff of Hollywood fantasy - but one woman has found traces of life within the fossilised bones of a T Rex.

Professor Richard Fortey travels across the globe to find the survivors of mass extinction events

In episode two, Fortey focuses on the 'KT boundary'. 65 million years ago, a 10 km diameter asteroid collided with the Earth and saw the end of the long reign of the dinosaurs.

The Day the Dinosaurs Died investigates the greatest vanishing act in the history of our planet - the sudden disappearance of the dinosaurs 66 million years ago.

About 20 million years before the appearance of the first dinosaurs, the biggest extinction the world had ever known had occurred. Towards the end of the Triassic, 220 million years ago, there was another extinction, which wiped out many of the non-dinosaurs including the dicynodonts such as Placerias and primitive archosaurs such as Postosuchus. It was after this that dinosaurs really started to radiate and diversify.

The earliest dinosaurs were pretty small. Eoraptor was only about 1 m long. However the plant-eating prosauropod, Plateosaurus, that appeared at the end of the Triassic period, was a harbinger of things to come.

While dinosaurs were ruling on land, the sea was the dominion of an entirely different group of animals: the marine reptiles. The programme concentrates on these amazing creatures that were every bit as awesome as their counterparts on land.

This episode is set in the early Cretaceous, a time when the world’s continents were breaking apart. It follows an enormous journey made by a giant pterosaur and many different geographical regions are covered in the programme.