Amazing new discoveries in South America are revolutionising what we thought we knew about the dinosaur world. It now seems that South America was home to both the largest meat-eater - so new it's still without a name - and the largest herbivore - the enormous long-necked Argentinasaurus. And what's more, these dinosaurs lived at the same time in the same place. So it's possible that like in a science fiction movie, in this prehistoric world these two giants of their kind fought each other in a spectacular clash of the Titans. Horizon follows the scientists to Argentina as they unearth one of these giants - a brand new species of dinosaur; the biggest carnivore ever discovered. Not yet named, this new creature is even bigger than T. rex, the so-called 'king' of the carnivores. The new giant South American predator had a skull bigger than a man that was full of serrated, knife-like teeth and long powerful jaw muscles. They could dissect their prey with almost surgical precision. B