UNDATED FILE PHOTO:  (EDITORIAL USE ONLY)  (FILE PHOTO)  U.S. President John Fitzgerald Kennedy is shown in this 1960 photograph. His presidential career spanned the Bay of Pigs invasion, the Cuban Missile Crisis and the building of the Berlin Wall. He was assassinated November 22, 1963 in Dallas, Texas. Former Russian and U.S. officials attending a conference commemorating the 40th anniversary of the missile crisis October 2002 in Cuba, said that the world was closer to a nuclear conflict during the 1962 standoff between Cuba and the U.S., than governments were aware of.  (Photo by Getty Images)