An asteroid or comet is thought to have impacted the Earth 66 million years ago, causing the extinction of the dinosaurs. The impact occurred in what is now the Yucatan Peninsula, leaving behind a crater 110 miles wide. The impact sent a massive amount of debris into the air, obscuring the sun and causing a global winter. This, combined with other effects such as wildfires, resulted in the extinction of many plants and animals, including the dinosaurs.