High Quality Content by WIKIPEDIA articles! Operation Alsos (or Alsos Mission) was an effort at the end of World War II by the Allies (principally Britain and the United States), branched off from the Manhattan Project, to investigate the German nuclear energy project, seize German nuclear resources, materials and personnel to further American research and to prevent their capture by the Soviets, and to discern how far the Germans had gone towards creating an atomic bomb. The personnel of the project followed close behind the front lines, first into Italy, and then into France and Germany, searching for personnel, records, material, and sites involved.