Most paleontologists believe that the Argentinosaurus was the largest dinosaur to have ever lived. It may have been the largest land animal to have ever existed.
Although a complete skeleton has not been found, researchers theorize that the animal could have measured up to 115 feet long and weighed up to 110 tons. This is based primarily on the large femur and backbone found by a rancher in 1987 in Argentina. Both fossil fragments were almost the size of a full-grown man. The specimen was described and announced in 1993, suggesting that the fossils dated back to the late Cenomanian faunal stage of the Cretaceous period, around 94 to 97 million years ago.