The Chicxulub crater is a large impact structure located on the Yucatán Peninsula in Mexico. It was formed about 66 million years ago when a massive asteroid, approximately 10 kilometers wide, struck the Earth. This event is widely believed to have contributed to the mass extinction of the dinosaurs and many other species at the end of the Cretaceous period. The crater measures about 150 kilometers in diameter and is buried beneath sediment. It was discovered in the late 1970s and has since been studied extensively by scientists. The impact created significant geological changes and left a lasting mark on Earth's history.