A decision to establish another European scientific facility, the long-awaited European Spallation Source (ESS), a next-generation, high-flux neutron source for Europe, is completed. There are three candidate sites to host the ESS, Bilbao in Spain, Debrecen in Hungary, and Lund in Sweden. The key advantage of the ESS for scientific research is that it uses a high power accelerator to propel protons at a target to produce well-defined pulses of neutrons. However, the decision to locate and build the ESS goes beyond national boundaries and requires the support of several European countries. The high neutron fluxes and the advanced neutron methods available at the ESS will allow scientists to look deep inside the structure of materials with unrivalled spatial and temporal resolution.