X-ray free electron lasers (XFELs) are particle accelerators that create pulses of light of extremely short duration, similar to that of some lasers used in eye surgery. Combined with the X-ray energy-domain, they enable a close examination of the shortest processes in nature – such as the way atoms move during a chemical reaction. Although Europe hosts some of the world-leading XFELs, the next generation may allow scientists to trace the motion of electrons in its entirety. This could make XFELs a poster case for investment in European research infrastructure or a moonshot project, with potential benefits for the European high-tech industrial sector.