Advertisement5 Defining Moments In The U.S.-Cuba RelationshipDecember 18, 2014Krishnadev CalamurfacebookEmailObama shakes hands with Castro during a memorial service for former South African President Nelson Mandela in Soweto, South Africa, on Dec. 10, 2013. Former Cuban leader Fidel Castro says his brother introduced himself to Obama in English, telling him, "Mr. President, I'm Castro," as the two leaders shook hands. (AP)