Tyrannosaurus rex and Brachiosaurus. Their names sound familiar, yet we only know what their bones tell us about them. Why are we so fascinated by these giants and why does their mass extinction intrigue us so much? Paleontologist Melanie During MSc (PhD-candidate Uppsala University) discovered that the meteorite that caused the dinosaurs to go extinct must have struck in spring, 66 million years ago. How did she make this stunning discovery? During is author of the Dutch book De laatste lente van de dinosauriërs.