A specific uranium compound has puzzled researchers for thirty years. Although the crystal structure is simple, no one understands exactly what is happening once it is cooled below a certain temperature. Apparently, a ‘hidden order’ emerges, whose nature is completely unknown.Now physicists have characterised this hidden order state more precisely and studied it on a microscopic scale. To accomplish this, they utilised the High-Field Magnet at the HZB that permits neutron experiments to be conducted under conditions of extremely high magnetic fields.