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The first shot sounded like a firecracker. The next two were unmistakably gunfire.

At the 40th anniversary of President John F. Kennedy's death, the moments remain frozen in the American psyche, the assassination still a source of fascination for historians, conspiracy theorists and an estimated 2.2 million people who visit Dealey Plaza each year.

"It's an age-old search for the truth," said Greg Silva, 39, a Hilmar, Calif., salesman who wasn't even born when Kennedy died but made it a point to visit The Sixth Floor Museum (search) at Dealey Plaza during a recent business trip to Dallas.

For others, the assassination endures as a deeply personal experience — a lingering mix of heartbreak, nostalgia and the lost promise of Camelot. Those emotions are clear at The Sixth Floor Museum.

"If you take people there that are old enough to remember the event, you lose them. They are back with their mother and father, sisters and brothers, aunts and uncles," said Greg Elam, spokesman for the Dallas Convention & Visitors Bureau.

"You can tiptoe away and they'll never know it because they are back in that experience."

Politics had brought the 46-year-old president to Texas, a pivotal and worrisome state in his 1964 re-election plans.

At the urging of local politicians, Kennedy ordered the reflective glass shield atop the presidential limousine removed for his visit to Dallas on Nov. 22, 1963. With first lady Jackie at his side, Kennedy smiled and waved at the crowds from the back seat. Up front, Gov. John Connally (search) and his wife, Nellie, beamed at the Texas welcome.

Just before 12:30 p.m., the motorcade slipped out of the glass and steel canyons of downtown and zigzagged toward Elm Street and a drab, seven-story brick building.

Then the shots rang out.

A half-hour later, Kennedy was declared dead at Parkland Memorial Hospital.

At 2:38 p.m., Vice President Lyndon B. Johnson was sworn in as president aboard Air Force One, with Jackie Kennedy at his side.

Forty years later, Kennedy remains an inspirational figure — a president more popular in death than in life.

"There's still so much sentiment for John F. Kennedy, and so much of it is colored by the assassination," said David Crockett, a political scientist at Trinity University (search) in San Antonio. "He's the young, attractive, tragic martyr figure assassinated on television, with a wife who's mourning."

When many Americans close their eyes, they can still see Kennedy's 3-year-old son, "John John," bravely saluting his father's flag-draped coffin.

After a 10-month investigation, the Warren Commission in 1964 concluded that Lee Harvey Oswald alone killed Kennedy, firing shots from the Texas School Book Depository's sixth floor.

Doubts lingered, however, and in 1978, Congress impaneled a committee to again investigate the assassination. The panel largely relied on the recording of a police motorcyclist's microphone.

The committee's conclusion: Four shots were fired, with one coming from a grassy knoll downtown. In other words, it concluded, Oswald didn't act alone.

But after further studies, the Justice Department in 1988 concluded there was no "persuasive evidence" of conspiracy, and formally closed the investigation.

Oswald was killed two days after Kennedy's assassination — gunned down by Dallas nightclub owner Jack Ruby as he was transferred from one jail to another.

A Dallas jury convicted Ruby of murder in 1964 and sentenced him to death. An appellate court ruling later set the verdict aside, and Ruby died of cancer in prison in 1967 before he could be retried.

Kennedy's daughter, Caroline Kennedy Schlossberg, who was four days shy of her 6th birthday when her father died, is the sole survivor of her immediate family.

Jacqueline Kennedy Onassis died of cancer in 1994 and John F. Kennedy Jr. died along with his wife and sister-in-law in the 1999 crash of a small plane he was piloting.

The crash brought still more pain to a family that dealt first with Kennedy's slaying, then with the assassination of his brother, Robert, during his 1968 presidential campaign.

All of which help explain the unending interest in all things Kennedy.

"They've just had great triumph and great tragedy," said Patrick Maney, a presidential historian at the University of South Carolina.

In Dallas itself, the anguish for some still seems as fresh as on that Friday afternoon 40 years ago.

"There are people who lived in Dallas in '63 who will never come to this site. It is too painful," said Jeff West, executive director of The Sixth Floor Museum, which chronicles Kennedy's life, death and the era in which he lived.

But for others, acknowledging Dallas' place in history helped the healing. "There are people who were here in '63 who are very proud and pleased that we did something to commemorate and mark the spot," West said.

Longtime residents recall how Dallas was labeled the city of hate — "Dallas was the only place ever blamed for killing a president," as historian Conover Hunt put it. Dallas residents talked about telephone operators disconnecting their calls and taxi drivers refusing to give them rides.

"People were spat upon, they were thrown out of restaurants all over the country and this went on for decades," said Hunt, original curator for The Sixth Floor Museum.

At the time, Dallas had a reputation as an ultraconservative city that didn't treat liberals kindly. The day before the assassination, handbills were distributed in Dallas with convict-style photographs of Kennedy and the caption: "Wanted for Treason."

The next day, a full-page ad appeared in The Dallas Morning News. The "American Fact-Finding Committee" demanded to know why the president had "ordered the Attorney General to go soft on communism."

So, when Kennedy was killed, the backlash was immediate.

"All of the nation experienced sadness. But I think the sadness that was experienced here in Dallas was of such great magnitude that it's almost hard to describe it," said Adelle Taylor, 72.

Taylor and her husband, Jim, work as tour guides at Southfork Ranch, made famous by the long-running hit television drama "Dallas," which, along with the emergence of the Dallas Cowboys as "America's Team," helped change the Big D's image.

"It's a little ironic that Dallas is known for the shooting of JFK and the shooting of J.R.," said Mark Thompson, sales and marketing director at Southfork Ranch, which draws more than 400,000 visitors a year.

For years after the assassination, many Dallas residents ignored sites connected with Kennedy's killing. Then the city tried to acknowledge the tragedy in 1970 by commissioning artist Philip Johnson to create a cenograph, or empty tomb, in a park two blocks from Dealey Plaza. An entire city block was renamed John F. Kennedy Memorial Plaza.

But the austere 30-foot blocks of white concrete that were meant to be a place for quiet reflection instead confused some visitors.

Eventually, Hunt and others raised $3.8 million in donations and loans to create The Sixth Floor Museum.

A few miles away, though, trash and pigeon droppings litter the front of the closed Texas Theatre, where police arrested Lee Harvey Oswald. The "E" has fallen off the makeshift "TEXAS" marquee that Oliver Stone put up for his 1991 movie, "JFK."

City voters have approved $500,000 of the $3 million needed to restore Dealey Plaza to its 1963 look. A group working to renovate the Texas Theatre has raised $2.4 million of the $3.5 million project cost.

The Oak Cliff Foundation envisions remaking the theater as a movie house and performing arts center with a lobby exhibit recounting the theater's role in history. Executive director Beverly Mendoza acknowledges surprise at the reactions she receives from some longtime residents asked to contribute.

"It just floored me," said Mendoza, who moved to Dallas in 1995, "for people to still be so ashamed of what happened here that they couldn't get beyond it to acknowledge it as a place of history."

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