The Rosenberg Executions

(Julius & Ethel Rosenberg during their trial)

Julius and Ethel Rosenberg were American Communists who were tried and convicted of conspiring to commit espionage by passing information about the atomic bomb to the Soviet Union. The Rosenbergs, as a result, were executed in Sing Sing Prison's electric chair on June 19, 1953. They became the first civilians to be executed for espionage in the history of the United States. 

(The Rosenbergs following their execution)

The Rosenberg execution remains controversial to this day. Ethel's involvement in the spy ring is believed by many to have been minimal at best, as supported by recently decoded Soviet cables codenamed VENONA.

Also in September, 2008, Morton Sobell, a co-defendant in the trial, admitted that he and Julius Rosenberg engaged in spying for the Soviets but that he believed that Ethel only knew of her husband's involvement and wasn't a participant.