At first glance, dinosaurs seem like the product of a wild imagination - how could such weird and wonderful creatures ever have existed on our Earth? Before the extinction event that changed the world forever, dinosaurs and their reptilian relatives of the sea and sky ruled the prehistoric world. We've gathered together some of the largest, fiercest and the weirdest of these amazing creatures, from the Allosaurus to Zuniceratops. Did Velociraptors hunt in packs? Why did the herbivores grow so massive? Find out how the dinosaurs survived and thrived, about the mass extinction that ended it all and what these creatures left behind to make us wonder.