Dreadnoughtus was a massive dinosaur that lived during the late Cretaceous period, around 77 million years ago. It belonged to the group of long-necked dinosaurs known as sauropods. Fossils of Dreadnoughtus were discovered in Argentina, and it is estimated to have weighed around 65 tons and measured about 85 feet long, making it one of the largest land animals ever. This dinosaur had a long neck and a large body, which helped it reach high vegetation for food. Its name means "fears nothing," reflecting its size and dominance in its environment. Dreadnoughtus likely lived in herds, providing safety in numbers against predators.