How fast can a magnet switch its orientation and what are the microscopic mechanisms at play? These questions are of first importance for the development of data storage and computer chips. Now, an HZB team at BESSY II has for the first time been able to experimentally assess the principal microscopic process of ultra-fast magnetism. The methodology developed for this purpose can also be used to investigate interactions between spins and lattice oscillations in graphene, superconductors or other (quantum) materials.