Fidel Castro's rebels take power as dictator Fulgencio Batista flees Cuba on Jan 1, 1959. The United States soon recognizes the new government. But relations begin to sour as Americans criticize summary trials and executions of Batista loyalists. In 1960 Cuba nationalizes U.S.-owned oil refineries after they refuse to process Soviet oil. Nearly all other U.S. businesses are expropriated soon afterward."
|From WSJ Article cited below|
Timeline of key dates in US relations with Cuba - AP Story
Also, see this article with photos and videos of the festivities: WSJ Article on U.S. Flag Being Raised at Embassy in Havana Cuba