This month, the American Museum of Natural History is adding another must-see to its legendary Fossil Halls: a cast of a 122-foot-long sauropod dinosaur. Putting it together is a pretty tall order, too.
A tooth recently discovered in Argentina is an incredible 75 millimeters, or nearly 3 inches long. What's more, the tooth belonged to a member of the titanosaurs, a group of gigantic sauropods similar to brachiosaurus and apatosaurus. And it might just be the biggest of the bunch.