President John F. Kennedy reaches out to the crowd gathered at the Hotel Texas Parking Lot Rally in Fort Worth,Texas, November 22, 1963.

President John F. Kennedy, his brother Senator Edward Kennedy and his daughter Caroline watch as President Kennedy's longtime friend Lem Billings (R) launches a toy sailboat given to Caroline by Italian president Antonio Sengi on the beach behind the family's home in Hyannis Port, Massachusetts, July 5, 1963. REUTERS/Cecil Stoughton/Office of the Military Aide to the President/John F. Kennedy Presidential Library

Then United States Congressman and future U.S. President John F. Kennedy (2nd L) walks in the Bunker Hill Day Parade in Charlestown, Massachusetts June 17, 1950.

President John F. Kennedy and first lady Jackie Kennedy watch the first of the 1962 America's Cup races aboard the USS Joseph P. Kennedy Jr., off Newport, Rhode Island, September 15, 1962.

President John F. Kennedy sits as his desk in the Oval Office while his son, John F. Kennedy Jr., looks out from underneath, at the White House, October 17, 1963.

President John F. Kennedy meets with Nikita Khrushchev, former chairman of the council of Ministers of the Soviet Union, at the U.S. Embassy residence in Vienna, Austria, June 1961.

President John F. Kennedy sits on a yacht with his daughter Caroline off Hyannis Port, Massachusetts, August 25, 1963.

President John F. Kennedy in an undated photograph courtesy of the John F. Kennedy Presidential Library and Museum.Reuters / JFK Presidential Library and Museum/Handout

John F. Kennedy and Jacqueline Kennedy arrive at the National Guard Armory for the inaugural ball in Washington, D.C., U.S. in January 1961. Ethel Frankau of Bergdorf Custom Salon designed the first lady's sleeveless gown and matching cape.

Former United States President John F. Kennedy (C) speaks during his inauguration ceremonies at the Capitol in Washington, in this handout photograph taken on January 20, 1961.

Former United States President John F. Kennedy and first lady Jackie Kennedy sit in a car in front of Blair House during the arrival ceremonies for Habib Bourguiba, president of Tunisia, in Washington, in this handout image taken on May 3, 1961. November 22, 2013 will mark the 50th anniversary of the assassination of President Kennedy.

Former U.S. President and then U.S. Navy Lt. John F. Kennedy is seen aboard the Patrol Torpedo boat PT-109 boat during World War II in the Pacific theatre, in this handout photograph taken on March 4, 1942. November 22, 2013 will mark the 50th anniversary of the assassination of President Kennedy. November 22, 2013 will mark the 50th anniversary of the assassination of President Kennedy.

President John F. Kennedy sits in a rowboat with his son John F. Kennedy Jr. on Bailey's Beach in Newport, Rhode Island, September 15, 1963.

President John F. Kennedy meets with his brother, former Attorney General Robert F. Kennedy, at the White House, October 3, 1962.

FILE PHOTO JUN53- Jacqueline Kennedy Onassis shown in this June 27, 1953 photograph with then Senator John F. Kennedy in Hyannisport, Massachuestts.

President John F. Kennedy signs a proclamation for the interdiction of the delivery of offensive weapons to Cuba during the Cuban missile crisis, at the White House, October 23, 1962.

President John F. Kennedy kisses his father Joseph P. Kennedy Sr. before boarding Marine One to depart Hyannis Port, Massachusetts, August 3, 1963.

President Kennedy meets with then Secretary of Defense Robert S. McNamara and Chairman of the Joint Chiefs of Staff General Maxwell D. Taylor in the Oval Office at the White House, October 2, 1963.

President John F. Kennedy sits onboard the U.S. Coast Guard yacht Manitou off the coast of Maine, August 12, 1962. REUTERS/Robert Knudsen/The White House/John F. Kennedy Presidential Library