Fifty years ago today, President John F. Kennedy died, a stunned nation grieved and a million conspiracy theories were born.

It was just after noon local time on Nov. 22, 1963, when the limousine carrying Kennedy entered Dealey Plaza in Dallas, its bubble top down so a smiling president, riding in the back seat with First lady Jackie Kennedy, could wave to an adoring crowd. The boyish president, a World War II Navy hero, author and former U.S. senator from Massachusetts, was just 46 and not quite three years into his first term as commander-in-chief.

"Kennedy had become a talented and incandescent politician. He had developed stage presence and star quality," wrote Thomas E. Cronin, author of "Leadership Matters," in a recent Denver Post editorial. "He served as president just as pride in America was at its peak."

A nation on the cusp of huge cultural shifts that would usher in civil rights for African Americans, the era of hippies, the Vietnam War and more heartbreaking assassinations, was still in an age of relative innocence. "The Andy Griffith Show" played on black and white televisions, a popular hit on solid state radios was "Blue Velvet" and the top movies included "The Great Escape."

Kennedy, in the home state of Vice President Lyndon Johnson, had a busy day lined up. He had spent the night at Hotel Texas in Fort Worth, read the Dallas Morning News — which on that day carried an ad accusing him of treason — and delivered two speeches before boarding Air Force One for a 15-minute flight to Dallas’ Love Field. The motorcade set off, via Main Street in downtown Dallas,  for the Trade Mart, where Kennedy was to deliver yet another speech. He and the first lady planned to spend the night at Johnson’s ranch near Austin.