In the series opener Stephen is transported back 155 million years to the Jurassic age when the dinosaurs grew into monsters. He meets a huge diplodocus and a deadly predator, the allosaurus. He learns how the diplodocus was able to rear up on its hind legs to feed in the treetops and tests the allosaurus’ bite. He also discovers how its colourful tail was used to attract a mate and how its sheer size helped fend off predators. "A diplodocus is absolutely massive, five times the size of an elephant," says Stephen. "It’s 6m high, that’s like a two-storey house, and 26m from tail to nose, which is like three double decker buses only longer!" Stephen also also unearths the fossilised remains of a nyasasaurus, the earliest dinosaur yet discovered, and learns how an allosaurus could open its axe-like jaw to an incredible 79 degrees, which allowed it to inflict large wounds on its prey.