Neutrons for research have been mainly produced in nuclear reactors until now, but we have come to realise that there are limits in using reactors to achieve higher intensities. That is why we turned to another technique, spallation. The spallation process First one accelerates protons to a high energy, and then one shoots them onto a target consisting of some heavy material in which there are many neutrons. The neutrons come out by a process that resembles evaporation. Spallation neutron sources provide these much sought-after particles in a more effective way. Also, when spallation takes place, there is no fission of atomic nuclei, and therefore no chain reaction. Neutrons are directed to a suite of neutron scattering instruments, each optimised to explore different properties of the microscopic structure of materials. ESS One step further Europe has the best spallation source there is at present, ISIS. Now we need to take the next step. In going from fission to spallation ESS will introduce a revolution in neutron science. Like a flash in photography allows to take photographs in the dark the very bright neutron flashes of ESS will very efficiently illuminate matter and will surpass the best existing neutron source, the reactor at the institute Laue-Langevin in Grenoble, by two orders of magnitude in intensity.