Scientists believe they have been given an amazing view of the last day of the dinosaurs after finding a fossil of an animal.
The perfectly preserved leg can be dated to the time when the asteroid that brought about the extinction of the dinosaurs hit Earth.
Phillip Manning is a professor of natural history at the University of Manchester. He told the Today programme that the thescelosaurus leg found at the Tanis dig site was the ultimate dinosaur drumstick.
The time resolution we can achieve at this site is beyond our wildest dreams. I never imagined that I would get to look at something that is time-constrained and beautiful, and also tell a wonderful story.
Sir David looked at the leg and smiled. Manning said that he agreed.
The remains of fish that breathed in impact debris from the asteroid strike were discovered by the team.
They were able to date the site much more accurately because of the debris that rained down immediately after the asteroid strike.
Robert DePalma, the University of Manchester graduate student who is leading the Tanis dig, said: "We have so many details with this site that tell us what happened moment by moment, it's almost like watching it." You look at the rock column and it brings you back to that day.
The remains of a turtle that was skewered by a wooden stake and small mammals and their burrows, as well as skin from a triceratops, a pterosaur embryo inside its egg, were found by the team.