Jacqueline Kennedy famously walked behind her husband's casket during his funeral procession in Washington ... the burial in November 1963. READ MORE: JFK files biggest bombshells from CIA ...

Billings was a former Choate classmate of JFK, who, as a younger man, served as something of a "go-between" for a young Jack Kennedy and the woman who would become Kennedy's wife, Jackie Bouvier ...

The limousine was used by Jackie Kennedy in the funeral procession for her husband, President John F. Kennedy in 1963. President Lyndon Johnson also used the limousine on many occasions.

Jackie Kennedy Was Advised to 'Ignore' Husband Aristotle Onassis' Romance with Maria Callas (Exclusive) Inside Jackie Kennedy and Maria Callas' Love Triangle with Aristotle Onassis from Someone ...