#7: Klaus Fuchs — Britain and Germany
Klaus Fuchs was a German-born physicist who worked on Britain’s wartime atomic program and the Manhattan Project. Motivated by communist conviction, he passed detailed nuclear information to the Soviet Union during and after World War II. British investigators arrested him in 1950 after he confessed. Fuchs received the maximum fourteen-year sentence under the Official Secrets Act, served nine years, then moved to East Germany, where he resumed a respected scientific career under the government there.
