Developments of new research areas and breakthroughs in science are often linked to the development of new instrumentation. Using superconducting accelerator technology, we propose to build the Ångström Laser (see Fig. 1): a source of high repetition rate femtosecond flashes of X-ray radiation that enable exploring materials on the ultimate quantum level of moving atoms and electrons. The Ångström Laser will be a discovery machine for new materials and novel sustainable technologies.