Cuba's leader Fidel Castro is helped into his chair by his brother Raul as he arrives to the National Assembly in Havana in 2004.

Fidel Castro stands with Soviet Premier Nikita Khrushchev, center left, in Harlem in 1960. Castro was in the U.S. during his first visit to the United Nations after coming to power.

Fidel Castro delivering a lengthy speech before the United Nations General Assembly in 1979.

Fidel Castro, bottom, looks out from a tank during the Bay of Pigs invasion in Cuba.

In this March 14, 1957 file photo, Fidel Castro, the young anti-Batista guerrilla leader, center, is seen with his brother Raul Castro, left, and Camilo Cienfuegos, right, while operating in the Mountains of Eastern Cuba.

Cuba's leader Fidel Castro, left, greets former Pope John Paul II in 1998.

In this Feb. 26, 1957 file photo, Cuba's leader Fidel Castro stands in an unknown location in Cuba.

Fidel Castro addresses a National Press Club luncheon in Washington, D.C. in 1959.

Cuban leaders walk arm-in-arm at the head of the funeral procession for the victims of the La Coubre explosion in 1960, blamed by the Cuban government on a U.S. bomb attack on the Cuban ship La Coubre in the harbor of Havana. From left to right are Cuba's leader Fidel Castro, Osvaldo Dorticos, Ernesto "Che" Guevara, Defense Minister Augusto Martinez-Sanchez, ecology minister Antonio Nunez-Jimenez, American William Morgan from Toledo, Ohio, and Spaniard Eloy Guttierez Menoyo.

Fidel Castro and Soviet Premier Nikita Khrushchev clasp hands at the Lenin mausoleum in Moscow's Red Square on May Day, 1963.