About 66 million years ago, an asteroid roughly 6 miles wide slammed into what is now the Yucatán Peninsula of Mexico. The crash blasted out a crater 110 miles across - bigger than many countries. It was the deadliest single event in Earth’s history. Around three-quarters of all species on the planet were gone soon after, including most dinosaurs.
The asteroid hit so hard that it sent burning rocks high into the sky and back down again, starting fires across continents. A thick cloud of dust and soot blanketed Earth, blocking sunlight for years. Without sunlight, plants died, plant-eaters starved, and the predators who hunted them followed. It was one bad day that lasted decades.
A few small animals survived because they could shelter underground, eat seeds, and live on very little. Some were the ancestors of birds. Others were the ancestors of every mammal alive today, including humans. Without the worst day in Earth’s history, you probably wouldn’t be reading this sentence.
