Size and Weight:
As you may have guessed from its name, the remains of Argentinosaurus were dug up in present-day Argentina, in South America. To date, researchers haven't found an entire skeleton, but what they have found--four-foot long vertebrae and five-foot-long tibiae--indicate that Argentinosaurus was a truly titanic sauropod (hence its classification in some circles as a titanosaur). See more facts, figures and news about Argentinosaurus and a gallery of Argentinosaurus pictures
Interestingly, the remains of Argentinosaurus were dug up near the fossils of another huge dinosaur--the carnivorous theropod Giganotosaurus. This has led paleontologists (and TV producers) to speculate that packs of Giganotosaurus may have hunted down full-grown Argentinosaurus adults--a chase that would have been deadly for any smaller creatures that happened to get in the way. (See this article for an analysis of an encounter between Giganotosaurus and Argentinosaurus.)
By the way, paleontologists in India have uncovered the remains of another dinosaur, Bruhathkayosaurus, that may have been even bigger than Argentinosaurus; the trouble is, no one is exactly sure what type of dinosaur Bruhathkayosaurus was!