DALLAS, Nov. 22 (UPI) -- Thousands of people gathered Friday in chilly rain under somber skies at Dealey Plaza, where President John F. Kennedy was assassinated 50 years ago.
There was a moment of silence at 12:30 p.m. CST -- the time three bullets cut short the life and promise of the youthful 46-year-old American president. Church bells rang and flags were flown at half-staff.
Security was tight for the 5,000 guests and news media at the ticketed event commemorating the 50th anniversary of the Kennedy assassination, with bomb-sniffing dogs and homeland security officers stationed near the former Texas School Book Depository Building, where a sixth floor museum now chronicles the assassination.
Some of those in attendance had vivid memories of that fateful day, Nov. 22, 1963.
"At first I could not believe it, then I went inside and watched the news on television for the rest of the day," Gary Chapman, who was 23 on that day a half century ago, told The Dallas Morning News.
Chapman, who brought his daughter to the Plaza, said it was her idea to attend the ceremony remembering the historic event.
"I remember there was a picture of Kennedy in our class," Wendell Pichon, who won his ticket in a lottery, told the newspaper. He was 5, just a first-grader, at the time of the assassination.
Former President George W. Bush did not attend and issued a written statement: "Today we remember a dark episode in our nation's history, and we remember the leader whose life was cut short 50 years ago. John F. Kennedy dedicated himself to public service, and his example moved Americans to do more for our country."
Every authorized attendee -- from the 5,000 members of the public who won tickets through a lottery to elected officials -- passed a police background check before getting permission to go to Dealey Plaza, authorities said.
Almost everyone, including elected officials, was brought to the memorial area by bus to control the pace of security checks for people entering the several-block-wide police perimeter.
Dallas police planned to use mobile surveillance cameras to monitor people's behavior and activities, Chief David Brown told City Council members before the event.
"It would be a profound embarrassment to the Dallas Police Department if anything were amiss that could be traceable to something that could have been prevented from planning better," security management Professor Robert McCrie of John Jay College of Criminal Justice in New York told the Morning News.
Dallas police were tight-lipped when United Press International sought additional information about security plans.
"We can't discuss any security measures that we're going to have," spokesman Officer Juan Fernandez told UPI.
The tribute -- the most prominent of scores of remembrances across the country -- "will reflect upon the president's life, legacy and leadership in a solemn and dignified commemorative event," the organizing President John F. Kennedy Commemorative Foundation said in a statement.
The Dealey Plaza event included speeches, hymns, patriotic musical performances, a Commemorative Air Force flyover salute and the unveiling of a monument to Kennedy.
The nation's 35th president was traveling with his wife Jacqueline, Texas Gov. John Connally and Connally's wife, Nellie, in a presidential motorcade.
A 10-month investigation in 1963 and 1964 by the Warren Commission concluded Kennedy was assassinated by Lee Harvey Oswald, acting alone, and Dallas nightclub owner Jack Ruby also acted alone when he killed Oswald before Oswald could stand trial.
The commission's findings are controversial and have been both challenged and supported by later studies.
The city restored the Dealey Plaza area for the commemoration. It replanted grass at the infamous grassy knoll, where Kennedy's presidential limousine was passing at the moment of the fatal head shot -- and where some witnesses said they saw what might have been a second gunman.
Period street lamps have been repaired.
The concrete pedestal where garment merchant Abraham Zapruder stood as he unexpectedly captured the assassination with his home movie camera has been freshly painted.