Dreadnoughtus

Dreadnoughtus schrani is a massive herbivorous dinosaur from the Campanian period of the Late Cretacous period. Around 35 meters or more, this dinosaur was in the top ten biggest dinosaurs. This couldn't have been attacked by a predator. It was found in Argentina and another massive sauropod of the same size lives here. The Patagosaurus lived here; and Tyrannosaurus rex lived in Canada.Dreadnoughtus schrani has an unknown size because the skeleton that was found was a juvenile, at 26 meters. This could've been the longest dinosaur ever if we ever find an adult-sized skeleton.