21) Cretaceous mass extinction wipes out the dinosaurs

Artist impression of a major meteorite impact with Earth. image source https://www.universetoday.com/135604/dinosaur-killing-asteroid-hit-exactly-wrong-place/

65 million years ago – Shortly after primates appear on the scene, the Cretaceous period ends with the 6th mass extinction after an asteroid 6 miles in diameter hits the Yucatan peninsula. The atmosphere fills with dust and smoke leading to a severe drop in temperature. This marks the end of the age of dinosaurs and the beginning of the age of mammals, the Cenezoic era. With the dinosaurs gone, the once dark and sheltered small mammals stride into daylight moving quickly to occupy available ecological niches.