<human>:  I have a question about the epoch of the Mesozoic Era. When did the extinction of the dinosaurs occur?
<bot>: The extinction of the dinosaurs occurred 65 million years ago. The extinction of the dinosaurs is often referred to as the Cretaceous-Tertiary extinction event, and it is the most well-known mass extinction event in Earth's history. The extinction of the dinosaurs is thought to have been caused by a series of asteroid impacts that occurred 65 million years ago.