Join Dr Philip Mannion and Dr Susannah Maidment at the Natural History Museum and meet creatures such as titanoboa, a 40 foot snake from prehistoric Columbia. A scientific rule called Cope's Law says that evolution always tends towards gigantism, but mass extinctions come along regularly enough to weed out most of the giant animals. Is this true? And what can the study of giant fossils tell us about the human driven extinction the world currently faces?