Before the dinosaurs, a million-year long volcanic eruption destroyed the ozone layer
It's known as the "Great Dying," an extinction event even more powerful than the one that killed the dinosaurs 65 million years ago. It's called the Permian-Triassic extinction event, and it took place 250 million years ago, before dinosaurs ruled the Earth. Scientists previously believed the Permian-Triassic extinction event happened because of a volcanic eruption. And not just any volcanic eruption... the volcanic eruption. Called the "Siberian Flood Basalts," this million-year-long volcanic eruption potentially caused the extinction of up to 96 percent of marine life, along with 70 percent of terrestrial vertebrate species.