The Otto Hahn Peace Medal in Gold is named after the German nuclear chemist and 1944 Nobel Laureate Otto Hahn, an honorary citizen of Berlin. The medal is in memory of his worldwide involvement in the politics of peace and humanitarian causes, in particular since the dropping of the atomic bombs on Hiroshima and Nagasaki in August 1945 by the United States Army Air Forces. It was established by his grandson Dietrich Hahn in 1988 and is awarded by the United Nations Association of Germany (Deutsche Gesellschaft für die Vereinten Nationen, DGVN, Berlin-Brandenburg) to persons or institutions that have rendered "outstanding services to peace and international understanding". By tradition, the gold medal, together with a leather-bound diploma inlaid in gold, is presented in Berlin at a biennial ceremony on 17 December by the Governing Mayor of Berlin and the President of the DGVN. On 17 December 1938, in Berlin-Dahlem, Otto Hahn and his assistant Fritz Strassmann discovered a new reaction in uranium (which exiled Lise Meitner and her nephew Otto Frisch two weeks later correctly interpreted as "nuclear fission") thus laying the scientific and technical foundations of nuclear energy. This 17 December 1938 therefore marks the beginning of the Atomic age, which from the scientific, political, economic, social and philosophical point of view has fundamentally changed the world.