Fifty-five years ago last weekend, John F. Kennedy, the president of the United States, was killed by a sniper’s bullet as he rode in an open car in Dallas.

For most old-timers, like me, it is a moment frozen in memory, like the end of World War II, the day Neil Armstrong walked upon the moon, or the day my first child was born.

If you don’t think so, ask any senior citizen.

I’ll bet he or she will tell you where they heard the news, and what it felt like to spend the next week glued to a fuzzy black and white TV set watching the national drama unfold.

In the next few years after President Kennedy died, we saw more political assassinations as gunmen killed Rev. Martin Luther King and Sen. Robert F. Kennedy. Another presidential candidate, Gov. George Wallace, was also shot but survived. Please, God, make sure that never happens again.

In 1963, President Kennedy was riding in a slowly rolling open limo amidst the usual cheers and jeers that a presidential visit draws even today.

As the Texas crowds waved, the presidential limo suddenly swerved out of line, racing towards Parkland Hospital’s emergency room.

Another car carrying Vice President Lyndon Johnson followed, as did another carrying the press pool reporters. Within a few moments, the president’s limo reached the hospital. The other cars were not far behind.

Merriman Smith, a legendary wire service reporter, was in the press pool car which slid into the hospital parking area not far from the presidential limo.

In his account of the incident, Smith said he ran to the side of the presidential car and saw the president face down on the back seat. Mrs. Kennedy was bent over him, cradling his head. Texas Gov. John Connolly, his chest stained with blood, was lying on his back on the floor next to his wife.

Smith, who was well known in the White House, saw Secret Service Agent Clint Hill, the head of the protection detail.

“How badly was he hit, Clint,” asked Smith.“He’s dead,” snapped Hill.

In the days before everyone had a cell phone, Smith ran down a hospital corridor and grabbed a phone and dictated these lines that were flashed around the world.

“Kennedy seriously wounded. Perhaps fatally by an assassin’s bullet.”

You know the rest of the story. The vice president was sworn into office and the president’s body was flown back to Washington, D.C. In the days to come, most of America put their lives on hold as our nation mourned.

As President Kennedy was rushed to the hospital, Lee Harvey Oswald walked out of the Texas Book Depository building. About 40 minutes later, he was confronted by a police officer and shot him dead. Oswald then slipped into a theater where he was spotted and arrested.

The next day, as TV cameras watched, Oswald was being transferred from his cell when Jack Ruby shoved a pistol in his chest and killed him.

The details of what happened next you can find online or in the history books.

That is where you will also find other takes on the Kennedy slaying. Conspiracy theorists have put out dozens of versions of what they believe happened and why. Some of them are, well, a little bit off the wall.

The Warren Report, the record of the official national inquest into the matter, concluded Oswald, a former U.S. Marine, was the shooter and that he acted alone. Some accounts doubt that Oswald could have aimed and fired three shots in the length of time the presidential motorcade passed the building where he was waiting.

But here is a part of the story few know.

A day or so after the slaying, CBS news, led by a young Dan Rather, convinced officials to let them reenact the shooting to see if someone could fire three shots from an Italian rifle of the same make and model used by Oswald.

Rather asked another young CBS reporter named Lew Wood, who had been a U.S. Marine, to play the role of the shooter.

Back in 1993, when I was a reporter in Indianapolis, I talked to Wood, who later became the news anchor on the Today Show.

Wood told me the details of the reenactment and how he stood in the sixth-floor window of the Texas Book Depository building holding the bolt action rifle. As the simulated presidential motorcade passed, he pretended to fire three shots.

For a trained rifleman, like Wood and Oswald, it was not a tough shot, Wood claimed. It was easy for him to fire, reload and fire two more times in the time it took for the president’s car to roll past his window.

Wood believed Oswald easily could have fired the shots that changed our history. So do I.