The first dinosaur remains, a mososaurian jaw more than a meter long, was unearthed near Maastricht, Holland, in 1770. As recounted by Desmond , it created a scientific sensation. With the discovery of a wealth of additional fossils during the 19th and 20th centuries, it became clear that the dinosaurs had evolved into a fantastic array of forms and sizes and were reigning supreme during the Mesozoic. It also became clear that they disappeared very abruptly near the peak of their success. What killed them remained a mystery that fascinated scientists for more than a century and generated a host of more or less implausible theories.