An international team of researchers from the Fritz Haber Institute of the Max Planck Society and the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) directly observed how angular momentum is transferred and conserved within a crystal lattice. Using intense terahertz laser pulses, the researchers were able to selectively control these processes, which unveiled a surprising effect: during the angular momentum transfer, the direction of rotation reverses – caused by the rotational symmetry of the material. The results provide new insights into the foundation of magnetism and open up possibilities for tailored control of quantum materials.