About 66 million years ago, a space rock about 6 miles across - roughly the size of Mount Everest - slammed into Earth at around 45,000 miles per hour. It came down in what’s now the Yucatán Peninsula in Mexico, leaving a crater about 110 miles wide.
The impact was unimaginable. It threw molten rock into the upper atmosphere, set forests on fire across continents, and kicked up so much dust that the entire Earth was blanketed in dark for years. Plants couldn’t photosynthesize. Plant-eaters starved. Meat-eaters starved soon after.
Within a few years, about 75% of all species on Earth - including every non-bird dinosaur - were gone forever. The ones that survived were mostly small: mammals living in burrows, freshwater animals, the smallest birds. From those survivors, eventually, came us.
