In Germany, just outside Frankfurt, is a place called the Messel Pit. Until 1971, the pit was used for quarrying iron ore and brown coal. But these were not all it contained: ever since the nineteenth century, a huge number of fossils have been dug up there. Although they are almost fifty million years old, they show the finest details of bird feathers, mammal fur, bat membranes and sometimes even the colours of insects. Fifty million years ago (fifteen million years after the disappearance of the dinosaurs), Europe had a tropical climate and was covered with tropical rainforest, like Brazil is today. In this new world, the mammals seized ‘power’ from the reptiles once and for all.