The dinosaurs went extinct about 66 million years ago during a sudden, catastrophic event known as the Cretaceous-Paleogene (K-Pg) extinction event. The most widely accepted cause of this mass extinction is the impact of a massive asteroid near the present-day Yucatán Peninsula, which created the Chicxulub crater. This asteroid hit the Earth with immense force, instantly vaporizing rock, triggering massive wildfires, tsunamis, and earthquakes. In the aftermath, debris and dust thrown into the atmosphere blocked sunlight, dramatically lowering temperatures and disrupting global climate. This led to a collapse of ecosystems and food chains. While some species died immediately, the environmental effects persisted for months or years, causing extensive extinction of about 75-80% of all species, including all non-avian dinosaurs. Some smaller animals that could seek refuge underground or underwater, such as small mammals and birds, survived and thrived after the event.