President John F. Kennedy greets supporters during his visit to Fort Worth, Texas, on Friday, November 22, 1963. This year marks 51 years since his assassination in Dallas, an event that jarred the nation and fueled a multitude of conspiracy theories about whether Kennedy was killed by a single gunman acting alone in the Texas School Book Depository. Here are some images from that fateful day as it unfolded. Houston Chronicle/AP

First lady Jacqueline Kennedy at a breakfast held by the Chamber of Commerce in Fort Worth with Vice President Lyndon B. Johnson, left, and Kennedy. Ferd Kaufman/AP

The Kennedys arrive at Love Field in Dallas on a trip to advance the upcoming 1964 campaign. Art Rickerby/Time Life Pictures/Getty Images

About 11:45 a.m., Texas Gov. John B. Connally Jr., waving to the crowd, and the Kennedys depart Love Field for a 10-mile tour of Dallas. The President asked about the weather earlier in the day and opted not to have a top on the limousine. Dallas Morning News

The Kennedys and Connallys leave Love Field with Secret Service Agent Bill Greer driving the presidential limousine. The motorcade is on the way to the Trade Mart, where Kennedy is to speak at a sold-out luncheon. Dallas Morning News

Crowds line the street as Kennedy's motorcade heads toward downtown Dallas. A group of White House staffers follows the motorcade in a bus several vehicles behind the presidential limousine. Dallas Morning News

Dallas Police Officer Bobby Hargis, background, is one of four motorcycle officers assigned to Kennedy's car, which reaches Houston Street shortly before 12:30 p.m. "I thought, 'Well, we've got it made now,' " Hargis said. "And then bam! It happens." Dallas Morning News

Kennedy is seen approximately one minute before he is shot. ap

Seen through the limousine's windshield as it proceeds along Elm Street past the Texas School Book Depository, Kennedy appears to raise his hand toward his head after being shot. The first lady holds Kennedy's forearm in an effort to aid him. James W. (Ike) Altgens/AP

Kennedy slumps against his wife as the bullet strikes him in the head. Connally, who is wounded in the attack, begins to turn around just to the left of Jackie Kennedy. Mary Ann Moorman/ap

Kennedy slumps in the back seat of the car and his wife leans over to him as Secret Service Agent Clinton Hill rides on the back of the car. Ike Altgens/AP

The limousine carrying the mortally wounded President races toward the hospital seconds after three shots are fired. Two bullets hit Kennedy and one hit Connally. Hill rides on the back of the car as the wives cover their stricken husbands. Justin Newman/ap

The limousine speeds along Elm Street toward the Stemmons Freeway overpass moments after shots are fired at Dealey Plaza. ap

Photographers are seen running shortly after the shooting. Art Rickerby/Time Life Pictures/Getty Images

Hurchel Jacks, Vice President Johnson's driver in the motorcade, listens with others to news accounts on the car radio outside the Parkland Hospital emergency entrance. After the shots were fired, Jacks had rerouted the vice president's car to safety. The ABC radio network broadcast the first nationwide news bulletin reporting that shots have been fired at the Kennedy motorcade. Dallas Morning News

Before 1 p.m., Dr. Tom Shires, with Parkland public relations director Steve Landregan, rear, describes the President's wounds to the press. Four doctors worked on the stricken Kennedy in the emergency room. Dallas Morning News

American broadcast journalist and anchorman Walter Cronkite removes his glasses and prepares to announce Kennedy's death. CBS broadcast the first nationwide TV news bulletin reporting on the shooting. CBS Photo Archive/Getty Images

A photographer captures a New Yorker's expression of shock upon hearing the news. At 1 p.m. the 46-year-old President of the United States is declared dead, becoming the fourth U.S. president killed in office. Stan Wayman/Time Life Pictures/Getty Images

After 2 p.m., Jacqueline Kennedy leaves Parkland Hospital with her slain husband's body. She would ride in the back with the bronze casket. "I had a feeling that if somebody had literally fired a pistol in front of her face that she would just have blinked," said Dallas Police Officer James Jennings, who helped put the casket in the hearse. Dallas Morning News

The hearse carrying Kennedy's body pulls away from Parkland Hospital en route to the airport. Ap

Lee Harvey Oswald, a 24-year-old ex-Marine, is arrested in the back of a movie theater where he fled after shooting Dallas Police Patrolman J.D. Tippit. That incident occurred approximately 45 minutes after the assassination. Archive Photos/Getty Images

Vice President Lyndon Johnson takes the oath of office to become the 36th president of the United States. He is sworn in by U.S. Federal Judge Sarah T. Hughes, left, with Jacqueline Kennedy by his side on Air Force One. Universal History Archive/Getty Images

The casket containing the body of President Kennedy is moved to a Navy ambulance from the presidential plane. Jacqueline Kennedy and Attorney General Robert Kennedy stand behind on the elevator. ap

Jacqueline and Robert Kennedy get into the Navy ambulance with the president's body at Andrews Air Force Base, just outside Washington. The body of the president is taken to Bethesda Naval Hospital for an immediate autopsy. AFP/Getty Images

Police mug shot of Lee Harvey Oswald. He is arraigned in the slaying of Officer Tippit on November 22 and/or the murder of the president the next day. As Oswald is being transferred from the Dallas city jail to the county jail, nightclub owner Jack Ruby shoots and kills him, an event captured live on TV. Ruby is arrested immediately. Donald Uhrbrock/Time Life Pictures/Getty Images