The Monument's astoundingly large collection of fossils was discovered by Earl Douglass in 1909, when he stumbled upon eight enormous dinosaur tailbones exposed on a sandstone ridge. Although most of the park's acreage is in Colorado, the Utah side features its prime attraction: the Quarry Exhibit Hall. Here you can view some 1,500 genuine fossils, displayed in their original burial positions in an excavated river bed, several stories high, 150-feet long, and now enclosed by a large, airy museum. A "touch wall" allows you to run your hands over some of the ancient bones, and various displays and dinosaur replicas help you put the jumble of bones in their prehistorical context. Use one of the interactive kiosks to identify the massive bones imbedded in the wall, or, better yet, flag down a ranger, who can add interesting tidbits about the bones and their excavation. To reach the Exhibit Hall, first stop by the Quarry Visitor Center, near the Monument's west entrance. There you can view a 12-minute video and see displays that give an overview of the site and its paleontogical significance. Then hop a shuttle (in summer) or drive (in winter) up to the Exhibit Hall.