Relations between the United States and Cuba, more strained than neighborly over the past century, have seen US occupations, Cold War enmity, and even the brink of nuclear war.

Here are some key events:

- 1898-1902 - After the Spanish-American War, the United States occupies former Spanish colony Cuba, pulling out only after Cuba agrees to terms making the island independent in name only.

- 1906 - The United States occupies Cuba again, staying three years.

- 1959 - Fidel Castro leads the ouster of US-backed dictator Fulgencio Batista.

- 1961 - After the United States breaks diplomatic relations with Cuba, the Central Intelligence Agency organizes the doomed Bay of Pigs invasion by Cuban exiles.

- 1962 - A US embargo launched in 1960 is expanded to cut off all trade with Cuba except food and medicine. Soviet missiles are then discovered in the country, sparking a tense nuclear standoff in October putting Washington and Moscow on the brink of war.

- 1965 - Cuba allows hundreds of exiles to sail to the United States in the October-November Camarioca boatlift. US president Lyndon Johnson establishes "freedom flights," and 260,561 Cubans would leave their country through the April 1973 end of the program.

- 1977 - US-Cuban relations improve slightly with the establishment of "Interests Sections" in each other's capitals.

- 1980 - The Mariel boatlift: Castro says anyone wanting to leave can do so through the port of Mariel, and about 125,000 refugees arrive in Florida by late September.

- 1996 - The US Congress passes the Helms-Burton Act strengthening the embargo against Cuba.

- 1999-2000 - Elian Gonzalez, a Cuban boy who survived a shipwreck while fleeing Cuba, becomes the focus of a six-month politically charged international custody battle. US eventually forcibly repatriates him.

- US President George W. Bush tightens the embargo even further, making it harder to travel or remit money to Cuba.

- May 2002 - Former US president Jimmy Carter visits Cuba, becoming the first US leader in or out of office to do so since Castro took power.

- November 2004 - Havana bars use of the US dollar as for commercial transactions, making the Cuban peso the only currency allowed in business transactions

- December 2008 - Latin American leaders at a summit in Brazil, call on the United States to lift the trade embargo.

- December 2009 - Alan Gross, a government contractor for the US Agency for International Development, is arrested for importing banned computer technology for distribution to Cuba's small Jewish community.

- March 2011 - Gross is sentenced to 15 years in prison for "acts against the independence or territorial integrity of the Cuban state." His conviction is seen as a major obstacle to improving relations between Washington and Havana.

- Spring 2013 - Obama authorizes exploratory negotiations with Cuba on normalizing ties

- June 2013 to November 2014 - The United States and Cuba hold a "series of discussions"

- Early summer 2014 - Pope Francis makes personal appeals in letters to presidents Obama and Castro, adding impetus to the talks

- Autumn 2014 - The Vatican hosts US and Cuban delegations in the final stages of normalization talks

- December 17, 2014 - Washington announces that Gross, 65, had been freed and was returning to America in exchange for three Cubans -- members of the so-called Cuban Five group of intelligence agents -- detained for years in the United States on espionage charges.

- US President Barack Obama, in a historic policy shift, announces that Washington will reestablish diplomatic ties with Cuba.

It also will ease a five-decade-long crippling economic embargo and lift travel sanctions against the communist island.

- Cuban President Raul Castro makes a speech at the same time as Obama, underscoring that a new era in their bilateral relations had begun.