one of the largest animals to have walked on land and trying to imagine it as a living, breathing creature is, yeah, it�*s amazing. the bones were unearthed at a ranch in patagonia in argentina just over a decade ago. as scientists got to grips with the scale of their find, they were joined by sir david attenborough. he also got a chance to see what this titan of the cretaceous period might have looked like. now the exhibition is complete, the dinosaur is ready for its moment in the spotlight. patagotitan still holds some mysteries. no—one knows why these creatures grew so big or how they came to die out, but their size and their success for millions of years puts our own existence into sharp perspective. rebecca morelle, bbc news. this is outside source live from the bbc newsroom. our lead story is that the white house has condemned