Fidel Alejandro Castro Ruz (; American Spanish: [fiel alexando kasto rus]; 13 August 1926 25 November 2016) was a Cuban revolutionary and politician who was the leader of Cuba from 1959 to 2008, serving as the prime minister of Cuba from 1959 to 1976 and president from 1976 to 2008. Ideologically a MarxistLeninist and Cuban nationalist, he also served as the first secretary of the Communist Party of Cuba from 1961 until 2011. Under his administration, Cuba became a one-party communist state; industry and business were nationalized, and state socialist reforms were implemented throughout society.

Born in Birn, Oriente, the son of a wealthy Spanish farmer, Castro adopted leftist and anti-imperialist ideas while studying law at the University of Havana. After participating in rebellions against right-wing governments in the Dominican Republic and Colombia, he planned the overthrow of Cuban President Fulgencio Batista, launching a failed attack on the Moncada Barracks in 1953. After a year's imprisonment, Castro traveled to Mexico where he formed a revolutionary group, the 26th of July Movement, with his brother Ral Castro and Ernesto "Che" Guevara. Returning to Cuba, Castro took a key role in the Cuban Revolution by leading the Movement in a guerrilla war against Batista's forces from the Sierra Maestra. After Batista's overthrow in 1959, Castro assumed military and political power as Cuba's prime minister. The United States came to oppose Castro's government and unsuccessfully attempted to remove him by assassination, economic embargo, and counter-revolution, including the Bay of Pigs Invasion of 1961. Countering these threats, Castro aligned with the Soviet Union and allowed the Soviets to place nuclear weapons in Cuba, resulting in the Cuban Missile Crisis a defining incident of the Cold War in 1962.

Adopting a MarxistLeninist model of development, Castro converted Cuba into a one-party, socialist state under Communist Party rule, the first in the Western Hemisphere. Policies introducing central economic planning and expanding healthcare and education were accompanied by state control of the press and the suppression of internal dissent. Abroad, Castro supported anti-imperialist revolutionary groups, backing the establishment of Marxist governments in Chile, Nicaragua, and Grenada, as well as sending troops to aid allies in the Yom Kippur, Ogaden, and Angolan Civil War. These actions, coupled with Castro's leadership of the Non-Aligned Movement from 1979 to 1983 and Cuba's medical internationalism, increased Cuba's profile on the world stage. Following the Dissolution of the Soviet Union in 1991, Castro led Cuba through the economic downturn of the "Special Period", embracing environmentalist and anti-globalization ideas. In the 2000s, Castro forged alliances in the Latin American "pink tide" namely with Hugo Chvez's Venezuela and formed the Bolivarian Alliance for the Americas. In 2006, Castro transferred his responsibilities to Vice President Ral Castro, who was elected to the presidency by the National Assembly in 2008.

The longest-serving non-royal head of state in the 20th and 21st centuries, Castro polarized opinion throughout the world. His supporters view him as a champion of socialism and anti-imperialism whose revolutionary government advanced economic and social justice while securing Cuba's independence from U.S. hegemony. Critics call him a dictator whose administration oversaw human rights abuses, the exodus of many Cubans, and the impoverishment of the country's economy.

Cuba ( (listen) KEW-bə, Spanish: [ˈkuβa] (listen)), officially the Republic of Cuba (Spanish: República de Cuba [reˈpuβlika ðe ˈkuβa] (listen)), is a country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribbean Sea, Gulf of Mexico, and Atlantic Ocean meet. Cuba is located at the east of the Yucatán Peninsula (Mexico), south of both the American state of Florida and the Bahamas, west of Hispaniola (Haiti/Dominican Republic), and north of both Jamaica and the Cayman Islands. Havana is the largest city and capital; other major cities include Santiago de Cuba and Camagüey. The official area of the Republic of Cuba is 109,884 km2 (42,426 sq mi) (without the territorial waters). The main island of Cuba is the largest island in Cuba and in the Caribbean, with an area of 104,556 km2 (40,369 sq mi). Cuba is the second-most populous country in the Caribbean after Haiti, with over 11 million inhabitants.The territory that is now Cuba was inhabited by the Ciboney Taíno people from the 4th millennium BC until Spanish colonization in the 15th century. From the 15th century, it was a colony of Spain until the Spanish–American War of 1898, when Cuba was occupied by the United States and gained nominal independence as a de facto United States protectorate in 1902. As a fragile republic, in 1940 Cuba attempted to strengthen its democratic system, but mounting political radicalization and social strife culminated in a coup and subsequent dictatorship under Fulgencio Batista in 1952. Open corruption and oppression under Batista's rule led to his ousting in January 1959 by the 26th of July Movement, which afterwards established communist rule under the leadership of Fidel Castro. Since 1965, the state has been governed by the Communist Party of Cuba. The country was a point of contention during the Cold War between the Soviet Union and the United States, and a nuclear war nearly broke out during the Cuban Missile Crisis of 1962. Cuba is one of a few extant Marxist–Leninist socialist states, where the role of the vanguard Communist Party is enshrined in the Constitution. Under Castro, Cuba was involved in a broad range of military and humanitarian activities throughout both Africa and Asia.Culturally, Cuba is considered part of Latin America. It is a multiethnic country whose people, culture and customs derive from diverse origins, including the Taíno Ciboney peoples, the long period of Spanish colonialism, the introduction of enslaved Africans and a close relationship with the Soviet Union in the Cold War.

Cuba is a founding member of the United Nations, the G77, the Non-Aligned Movement, the Organisation of African, Caribbean and Pacific States, ALBA and the Organization of American States. It has currently one of the world's only planned economies, and its economy is dominated by the tourism industry and the exports of skilled labor, sugar, tobacco, and coffee. Cuba has historically – both before and during Communist rule – performed better than other countries in the region on several socioeconomic indicators, such as literacy, infant mortality and life expectancy.Cuba has a single-party authoritarian regime where political opposition is not permitted. There are elections in Cuba, but they are not considered democratic. Censorship of information (including limits to internet access) is extensive, and independent journalism is repressed in Cuba; Reporters Without Borders has characterized Cuba as one of the worst countries in the world for press freedom.