Paleontology Collections Manager Carl Mehling gives us a behind-the-scenes tour of the Big Bone Room, which houses some of the largest items in the Paleontology collection. Its holdings include one of the largest complete limb bones in the world: the 650-pound thigh bone of the long-necked, plant-eating dinosaur Camarasaurus.

Visitors will be able to see this spectacular specimen in the upcoming major exhibition The World's Largest Dinosaurs (April 16, 2011-January 2, 2012), which explores the amazing anatomy of a uniquely super-sized group of dinosaurs, the sauropods.

More than 3 million specimens make up the Museum's world-class paleontology collections, and only a small fraction can be displayed at any given time. In fact, only 0.02 percent of the Museum's vertebrate paleontology specimens are on view; the rest are stored behind the scenes, where they continue to be studied by Museum scientists and their colleagues.