Question: The Zapruder film shows President John F. Kennedy's motorcade as it passed through a plaza that was named aNational Historic Landmark in what year? 

Context:
Umbrella man (JFK assassination)
The "umbrella man", identified by the United States House Select Committee on Assassinations in 1978 as Louie Steven Witt, is a name given to a figure who appears in the Zapruder film, and several other films and photographs, near the Stemmons Freeway sign within Dealey Plaza during the assassination of John F. Kennedy.
Warren Commission
The President's Commission on the Assassination of President Kennedy, known unofficially as the Warren Commission, was established by President Lyndon B. Johnson through Executive Order on November 29, 1963 to investigate the assassination of United States President John F. Kennedy that had taken place on November 22, 1963.
 The U.S. Congress passed Senate Joint Resolution 137 authorizing the Presidential appointed Commission to report on the assassination of President John F. Kennedy, mandating the attendance and testimony of witnesses and the production of evidence.
 Its 888-page final report was presented to President Johnson on September 24, 1964 and made public three days later.
 It concluded that President Kennedy was assassinated by Lee Harvey Oswald and that Oswald acted entirely alone.
 It also concluded that Jack Ruby also acted alone when he killed Oswald two days later.
 The Commission's findings have proven controversial and have been both challenged and supported by later studies.
Zapruder film
The Zapruder film is a silent, color motion picture sequence shot by private citizen Abraham Zapruder with a home-movie camera, as U.S. President John F. Kennedy's motorcade passed through Dealey Plaza in Dallas, Texas, on November 22, 1963, thereby unexpectedly capturing the President's assassination.
Orville Nix
Orville Orhel Nix (April 16, 1911 – January 17, 1972) was a witness to the assassination of U.S. President John F. Kennedy in Dallas, Texas, on November 22, 1963.
 His filming of the event, capturing only the last few seconds of the drama, is considered nearly as important as the Abraham Zapruder film.
Marilyn Sitzman
Marilyn Sitzman (December 14, 1939 – August 11, 1993) was an American receptionist and a witness to the assassination of U.S. President John F. Kennedy in Dallas, Texas on November 22, 1963.
 She was with her boss, Abraham Zapruder, as he made the Zapruder film, the most studied record of the assassination.
Abraham Zapruder
Abraham Zapruder (May 15, 1905 – August 30, 1970) was a Russian-born American clothing manufacturer who witnessed the assassination of President John F. Kennedy in Dallas, Texas, on November 22, 1963.
 Zapruder unexpectedly captured the event in a home movie while filming the presidential limousine and motorcade as it traveled through Dealey Plaza.
Lee Harvey Oswald
Lee Harvey Oswald (October 18, 1939 – November 24, 1963) was an American former U.S. Marine who assassinated United States President John F. Kennedy on November 22, 1963.
 According to four federal government investigations and one municipal investigation, Oswald shot and killed Kennedy as the President traveled by motorcade through Dealey Plaza in the city of Dallas, Texas.
William Greer
William Robert Greer (September 22, 1909 – February 23, 1985) was an agent of the U.S. Secret Service, best known for having driven President John F. Kennedy's presidential limousine in the motorcade through Dealey Plaza in Dallas on November 22, 1963, when the president was assassinated.
Assassination of John F. Kennedy
John F. Kennedy, the 35th President of the United States, was assassinated on Friday, November 22, 1963 at 12:30 p.m. Central Standard Time in Dallas, Texas while riding in a motorcade in Dealey Plaza.
 Kennedy was fatally shot by a former U.S Marine, Lee Harvey Oswald, while he was riding with his wife, Jacqueline, Texas Governor John Connally, and Connally's wife, Nellie, in a presidential motorcade.
 A ten-month investigation by the Warren Commission from November 1963 to September 1964 concluded that Oswald acted alone in shooting Kennedy, and that Jack Ruby also acted alone when he killed Oswald before he could stand trial.
 Kennedy's death marked the fourth (following Lincoln, Garfield, and McKinley) and most recent assassination of an American President.
 Vice President Lyndon B. Johnson became President upon Kennedy's death.
Dealey Plaza
Dealey Plaza , in the historic West End district of downtown Dallas, Texas (U.S.), is the location of the assassination of John F. Kennedy on November 22, 1963.
 The Dealey Plaza Historic District was named a National Historic Landmark in 1993 to preserve Dealey Plaza, street rights-of-way, and buildings and structures by the plaza visible from the assassination site, that have been identified as witness locations or as possible assassin locations.

Answer: 1993