The Cretaceous-Paleogene extinction event, occurring around 66 million years ago, marks a significant turning point in Earth's history. This event led to the extinction of approximately 75% of all species, including the non-avian dinosaurs. Scientists believe a combination of factors, including a massive asteroid impact and volcanic activity, contributed to this dramatic loss of biodiversity. The impact of the asteroid created the Chicxulub crater in present-day Mexico, releasing energy equivalent to billions of atomic bombs. This catastrophic event caused widespread fires, tsunamis, and a "nuclear winter" effect, drastically altering the climate. The extinction paved the way for the rise of mammals and eventually the evolution of humans.