Academy expertDr. Joseph Leidy, shown here with a leg bone from Hadrosaurus, was the museum's paleontologist in the mid 1800s. Dr. Leidy was one of the first to propose that some dinosaurs may have walked on two legs.

Famous dinosaur artistIn this illustration, British sculptor Benjamin Waterhouse Hawkins appears in front of the Hadrosaurus skeleton he created for the Academy of Natural Sciences in 1868. This was the world's first free-standing mount of a dinosaur. Hawkins first became known to dinosaur enthusiasts when he collaborated with Sir Richard Owen to create a display of prehistoric creatures for the Crystal Palace in London, England.

Tyrant lizards on displayTyrannosaurus rex means "tyrant lizard king." As you can see from this exhibit, the dominant feature of this dinosaur was its massive head and sharp teeth. Any plant-eater would have run when it saw this monster approaching!

Exotic expeditionsThrough the years, the museum has sponsored many expeditions, including those to the Gobi Desert in Mongolia in the 1920s. The explorers found a number of unique dinosaur skeletons, as well as fossilized nests and eggs. Here you can see the expedition's camel caravan.

Spectacular skeletonsThere are so many dinosaur skeletons in this hall that it looks like they could reach out and grab you. Watch your step in this place—dinosaurs are everywhere!

Famous fossil hunterMany of the exhibits in this museum were excavated by Earl Douglass, shown here with Apatosaurus fossils in the field. Douglass, funded by the museum in the early 1900s, found numerous dinosaur bones in the area now known as Dinosaur National Monument.

Model monsterEven the skeleton of Tyrannosaurus rex looks intimidating. For a view of what the complete dinosaur looked like, you can check the painting on the wall behind.

Field workBefore any dinosaur appears in a museum, its fossils must be excavated in the field. Here is a photograph of a famous discovery in 1916. The bones in the foreground belonged to Diplodocus, one of the largest sauropods. You can see that dinosaur skeletons don't come neatly put together!

Tough territoryMany fossils in Dinosaur National Monument were embedded in hillsides and had to be carried out by horse-drawn wagons.

Famous collector and climberEarl Douglass, shown here scaling a cliff in the park, found his first dinosaur here in 1909, and spent the next fifteen years digging up dinosaurs in the area.

In the fieldNo dinosaur skeleton ever walked on its own into a museum. All the bones start out all mixed up and buried in rock formations. This worker is shown next to a Brachiosaurus thigh bone. Imagine lifting a fossil this big!

"Illinois Jones"Paul Sereno has been in the spotlight several times for his incredible discoveries of dinosaurs. Most recently, Sereno made the front pages of newspapers around the world for his discovery of one of the most primitive dinosaurs known, Eoraptor. Sereno is a paleontologist at the University of Chicago.

One of the biggest yetHere Dr. James Jensen is shown with the leg bones of Ultrasauros, a sauropod whose fossils Jensen discovered. Imagine how huge the complete dinosaur was!

Upper shoulder boneThis is only a shoulder bone from a giant sauropod named Supersaurus. Paleontologist James Jensen, who found the fossils of the dinosaur, appears beside it.

Resident expertPaleontologist Jack Horner, renown for his studies of dinosaur eggs and nests, is the paleontology curator of the museum.

Eggy evidenceDinosaur eggs found in Montana actually contained fossilized dinosaur embryos! This model shows what they looked like.

Mother and baby MaiasauraThis dinosaur was named "good mother lizard" because fossils indicate that the adults may have cared for the babies instead of abandoning them.

Building the beastsHere, a worker reconstructs a dinosaur while an audience looks on.

Famous contributorIn the mid to late 1800s, Othniel Charles Marsh raced to beat rival American dinosaur hunter Edward Drinker Cope in finding the most dinosaurs. Although Marsh made some embarrassing mistakes along the way, at the end of the "dinosaur rush" he had described a greater number of dinosaurs than Cope. Marsh's work was funded by the Peabody Museum.

Diplodocus and RhamphorhynchusWhile sauropods like Diplodocus grazed below, pterosaurs like Rhamphorhynchus soared overhead.

Utah State paleontologistDr. David Gillette, shown here plastering a stegosaur fossil, oversees dinosaur research projects for the state of Utah. One of Gillette's most exciting discoveries is Seismosaurus, whose fossils have not yet been fully excavated. Seismosaurus may prove to be the largest dinosaur ever found!

Rugged territoryThe dinosaurs in the museum were excavated from Dinosaur Provincial Park, where the badlands are amazingly rich in dinosaur fossils.

TriceratopsImagine coming face to face with this huge, horned dinosaur! The Earth was a very different place when the dinosaurs ruled it than it is now.

A leader in his fieldA curator of the museum, Dr. Philip Currie, is well known for his studies of meat-eating dinosaurs, as well as his discoveries in Canada and in China.