A posthumous portrait of U.S. president John F. Kennedy, completed by Aaron Shikler in 1970. Kennedy was assassinated on November 22, 1963, in Dallas, Texas. Lee Harvey Oswald was arrested that evening for the crime, but was killed by Jack Ruby two days later, before a trial could take place. The FBI and the Warren Commission officially concluded that Oswald was the lone assassin, but conspiracy theories persisted. In 1978, a select committee concluded that both investigations were flawed and that the assassination was probably the result of a conspiracy.Painting: Aaron Shikler