The largest land animal ever to have lived is the **Argentinosaurus**, a massive sauropod dinosaur. Spanning over 100 feet in length and weighing up to 100 tons, it roamed the Earth during the Late Cretaceous period, around 94 to 97 million years ago. This giant herbivore had a long neck and tail, which allowed it to reach high into trees for food. Fossils of Argentinosaurus have been found in Argentina, contributing to our understanding of the diversity and size of dinosaurs. Its sheer scale continues to capture the imagination of both scientists and the public alike.