The well-preserved tracks were left in the silt by a species of bird that would have made even today's ostriches seem tame.
Palaeontologists have successfully unearthed the most complete skeleton of a terror bird ever found.
Once thought to have been a vicious predator, the 7ft terror bird was actually a harmless plant-eater.
These giant, flightless birds that roamed South America 50 million years ago would have been fearsome predators.