The European Spallation Source, or ESS, is state-of-the-art science facility being built in Lund, Sweden by a collaboration of 13 European nations. Almost like a giant microscope, ESS will allow scientists to use neutrons to look deep inside objects to see where the atoms are and what they are doing. This can help them design new materials which could lead to better batteries, greener plastics or stronger engineering materials. Or, it could help life science researchers develop new vaccines or more effective medicines. ESS is one of the largest science and technology infrastructure projects being built today. The facility design and construction includes the most powerful linear proton accelerator ever built, a 4-tonne, helium-cooled tungsten target wheel, 22 state-of-the-art neutron instruments, a suite of laboratories, and a supercomputing data management and software development centre. In the context of its history and future as a scientific organisation, however, it is more than the sum of its parts. It is a brand new organisation, being built from the ground up.