Roughly 66 million years ago our planet went through one of the most large-scale extinction events in the history of multicellular life forms. Entire classes of species were wiped off the face of the Earth. Others changed beyond all recognition in order to adapt to the new conditions and survive. The reasons for this tremendous event are still not known for certain. Still, there is no doubt that the Cretaceous-Paleogene Extinction made dramatic changes to what our planet looked like. The majestic and horrifying dinosaurs were succeeded by creatures not less impressive – mammals.