#HellCreek is one of the world’s most famous paleontological sites. It is here that fossils of some of the last non-avian dinosaurs, which lived just before the asteroid impact 66 million years ago, have been discovered. 66 million years ago, this region was a vast subtropical landscape filled with forests, wetlands, and swamps. Among towering trees and dense vegetation lived some of the most iconic dinosaurs, including #Tyrannosaurus, #Triceratops, #Edmontosaurus, #Ankylosaurus, and Pachycephalosaurus.