The Korean National Research Institute of Cultural Heritage (NRICH) under the Cultural Heritage Administration revealed the world's first hard proof of dinosaur courtship in the Cretaceous period based on trace fossil evidence found in Colorado, the United States. This discovery is an achievement of joint research project between Korean NRICH and U.S. University of Colorado from 2011 through 2014 as part of international comparative study for the inscription of dinosaur fossil sites in southern coast of Korea onto the UNESCO World Heritage List. Over 50 fossils discovered in two Western Colorado and one Eastern Colorado provide the detailed description of not only male Cretaceous dinosaurs' courtship behaviors but also female dinosaurs' sexual selection. This remarkable research was published in Scientific Reports on January 7, 2016 titled as Theropod courtship - large scale physical evidence of display arenas and avian-like scrape ceremony behaviour by Cretaceous dinosaurs.