Scientists are piecing together remnants of the day the extinction of the dinosaurs began. According to The New York Times, scientists studying a site in North Dakota believe they have discovered pieces of an asteroid that slammed into Earth about 66 million years ago off the Yucatán Peninsula. It's believed the object caused widespread destruction and led to the eventual extinction of the dinosaurs, which paved the way for mammals to rule the planet. When the asteroid hit, it created a 20-mile-deep crater that sent molten debris into the air that later cooled into "spherules of glass," the newspaper explained. Experts say these objects are unmistakable signs that an asteroid impact occurred. Over millions of years, some of the spherules have been altered due to interactions with the environment. However, at the North Dakota site – called Tanis – some of the spherules have been preserved in amber, the Times reported. Robert DePalma, an adjunct professor and University of Manchester graduate student, said Tanis researchers have found spherules containing pieces of unmelted rock. When testing the fragments, they discovered that not only did they contain portions of limestone crust from the impact crater thousands of miles away, but some pieces included high amounts of iron, nickel, and chromium. These elements are consistent with asteroid material, and could possibly be from the one that collided with Earth that fateful day. Additionally, DePalma said a preserved leg of a dinosaur that may have died the day the asteroid hit has been found at the Tanis site.