November 22, 1963: President Kennedy killed
Jacquelyn Kennedy walks with her children after her husband's death.
(CNN) -- On a sunny fall day in Dallas, Texas, President John F. Kennedy's motorcade rolled through Dealey Plaza. The youngest ever elected American president waved to the crowds around him from his convertible limousine, wife Jacquelyn at his side.
Then the shots rang out. Within hours, doctors pronounced Kennedy dead and Lyndon B. Johnson was sworn in as U.S. commander-in-chief. And a country mourned.
"No president had been assassinated in this country since 1901," said Jack Valenti, then a White House special assistant.
We may not know the whole story in our lifetime.
-- Supreme Court Chief Justice Earl Warren
A young, charismatic leader's death rocks the United States
"That this gallant, urbane, very witty and very popular president was [killed] in a senseless act of malice had an overpowering effect on the country."
A little more than an hour later, 24 year old Lee Harvey Oswald was arrested for shooting Dallas Police Officer J.D. Tippit. Authorities would come to believe it was Oswald who shot Kennedy with a rifle from the sixth floor of the Texas School Book Depository.
Two days later, Oswald was fatally shot by Jack Ruby, who himself died four years later in prison while awaiting a new trial.
The Warren Commission, which investigated the assassination, found no evidence that linked Oswald, a U.S. citizen who once defected to the Soviet Union and 1962, to a conspiracy to assassinate President Kennedy.
But that finding did not stop the growth of countless conspiracy theories, linking Kennedy's murder to everyone from Cuban leader Fidel Castro to the U.S. government.