Here are some key events in US-Cuba relations in the last half-century:
Jan. 1, 1959 - US-backed dictator Fulgencio Batista flees Cuba as Fidel Castro and his revolutionaries seize control.
April 19, 1959 - Fidel Castro, as prime minister, meets US Vice President Richard Nixon in what will become the highest-level talks between the two countries for decades.
Jan. 3, 1961 - The United States breaks off diplomatic relations with Cuba after the nationalization of US-owned properties.
April 16, 1961 - Castro declares his revolution is socialist. The next day, CIA-backed Cuban exiles try to invade Cuba at the Bay of Pigs, but are defeated.
Feb. 7, 1962 - The United States ramps up sanctions it has imposed since 1960, imposing a complete commercial embargo against Cuba that remains in place.
October 1962 - The United States discovers Soviet nuclear missiles on Cuba, leading to a showdown with the Soviet Union that almost leads to war. The confrontation ends with the Russians removing the missiles and the United States agreeing never to invade Cuba and, secretly, pulling its missiles from Turkey.
April-October 1980 - Cuba allows 125,000 people to travel to the United States from the port of Mariel in what becomes known as the Mariel Boatlift.
December 1991 - The Soviet Union, Cuba's biggest benefactor, collapses, touching off an economic crisis from which the island has not fully recovered.
August-September 1994 - More than 35,000 people leave Cuba in fragile boats, headed for the United States.
July 31, 2006 - Fidel Castro provisionally turns over power to his brother, Raul Castro, after undergoing emergency intestinal surgery.
Feb. 24, 2008 - The National Assembly elects Raul Castro to formally replace the ailing Fidel Castro.
December 2009 - Cuba arrests Alan Gross. It later sentences the US Agency for International Development subcontractor to 15 years in prison after accusing him of importing banned technology and trying to establish a clandestine Internet service.
January 2011 - The White House loosens travel restrictions on Cuba to allow "people-to-people" contact.
Dec. 17, 2014 - Gross is released and flown back to the United States, and a spy held in Cuba is freed in exchange for three Cuban intelligence agents held in America. Washington and Havana announce they will work to restore diplomatic relations and President Barack Obama says he will ease many commercial restrictions.
Jan. 15, 2015 - US government announces a series of relaxations of trade and travel restrictions, in line with Obama's announcement, but the overall trade embargo remains in place.
Jan. 22, 2015 - Senior US and Cuban diplomats a hold first round of talks in Havana to discuss restoring diplomatic ties and opening embassies.
April 11, 2015 - Obama and Raul Castro meet for talks as both attend a regional summit in Panama. They agree to push ahead to improve relations and restore full diplomatic ties.