For the development of new medicinal agents, accurate knowledge of biological processes in the body is a prerequisite. Here proteins play a crucial role. At the Paul Scherrer Institute PSI, the X-ray free-electron laser SwissFEL has now, for the first time, directed its strong light onto protein crystals and made their structures visible. The special characteristics of the X-ray laser enable completely novel experiments in which scientists can watch how proteins move and change their shape. The new method, which in Switzerland is only possible at PSI, will aid in the future discovery of new drugs.