This is the skull of the most complete Tyrannosaurus rex ever found. The Black Hills Institute of Geological Research in Hill City, South Dakota excavated it. This picture was taken on Nov. 2003 at the Smithsonian National Museum of Natural History.
The controversial discovery of soft tissue preserved in the bones of dinosaurs for millions of years finally gets an explanation. According to new research, iron in the dinosaurs' blood acts as a preservative, keeping the tissues safe from decay.