"Allosaurus" was used as the starring dinosaur of the 1956 film "The Beast of Hollow Mountain", and the 1969 film "The Valley of Gwangi". Gwangi is billed as an "Allosaurus", though Ray Harryhausen based his model for the creature on Charles R. Knight's depiction of a "Tyrannosaurus". "Allosaurus" appeared in the second episode of the 1999 BBC television series "Walking with Dinosaurs" and the follow-up special "The Ballad of Big Al", which speculated on the life of the 'Big Al' specimen, as revealed by the numerous injuries and pathologies in its skeleton.