It was the briefest of moments, just seconds, two presidents shaking hands and exchanging pleasantries amid a gaggle of world leaders together to honor the late Nelson Mandela.
It would hardly have been noteworthy, except the men locking hands in Johannesburg were Barack Obama and Raul Castro, whose nations have been mired in Cold War antagonism for more than five decades.
Not everyone was so happy about it.
"Sometimes a handshake is just a handshake, but when the leader of the free world shakes the bloody hand of a ruthless dictator like Raul Castro, it becomes a propaganda coup for the tyrant," said Rep. Ileana Ros-Lehtinen, a Cuban-American congresswoman from Miami.
Obama adviser Ben Rhodes said the handshakes were not planned in advance and didn't involve any substantive discussion.
Exchanges between American and Cuban leaders are rare, with U.S. officials preventing even passing encounters between them. In 1959, Fidel Casto visited the United States just months after his forces overthrew Cuban dictator Fulgencio Batista. U.S. officials were already wary of Fidel Castro, and President Dwight Eisenhower went out of his way to avoid meeting him. That left the task of a get-together to Vice President Richard Nixon.
In 2000, President Bill Clinton shook hands with Fidel Castro when the Cuban leader approached him at the end of a United Nations luncheon in New York. White House officials said at the time that the brief exchange was not substantive.
When South African President Jacob Zuma walked into the stadium for the memorial service of Nelson Mandela, he drew a cheer from the ruling African National Congress crowd. But then little by little, the booing started.
In what should have been Zuma's finest hour, the people were jeering him.
At one point, deputy president and master of ceremonies Cyril Ramaphosa, who appeared taken aback by the crowd's reaction, told them to be disciplined.
The booing died down when Zuma addressed the crowd. But in contrast to the spontaneous applause that burst forth throughout Obama's speech, people chatted during much of Zuma's address and those of other world leaders.
The former Anglican archbishop of Cape Town, Desmond Tutu, later scolded the crowd for lack of discipline during a closing ceremony, demanding a pin-drop silence and getting it.
It wasn't all solemnity at Nelson Mandela's memorial service. President Barack Obama and British Prime Minister David Cameron leaned in to pose for a selfie with Danish Prime Minister Helle Thorning-Schmidt at a vast soccer stadium where Mandela was honored. Obama's wife, Michelle, sat unsmiling next to her husband, out of the picture, which was captured by a photographer at the event. Other pictures taken during the memorial show Obama chatting with the Danish prime minister, and Mrs. Obama talking with her, as well.
Foul weather and public transportation problems kept many people away. But the rain was seen as a blessing among many of South Africa's majority black population. "In our culture the rain is a blessing," said Harry Tshabalala, a driver for the Justice Ministry. "Only great, great people are memorialized with it. Rain is life. This is perfect weather for us on this occasion."
Mandela's widow, Graca Machel, and former wife Winnie Madikizela-Mandela were at the stadium, and gave each other a long hug before the ceremonies began. So were actor Charlize Theron, model Naomi Campbell and singer Bono.
A joint wave from Air Force One, a shared dinner, and a long flight home. President Barack Obama and former President George W. Bush shared quality time Tuesday as they returned from Nelson Mandela's memorial service in South Africa.
Bush and his wife, former first lady Laura Bush, had round-trip passage with Obama and first lady Michelle Obama.
As Obama and Michelle Obama boarded the presidential jet Tuesday, they waited at the top of the stairs for the Bushes to climb the steps behind them. At the threshold of the plane's fore cabin, Obama encouraged Bush and the two wives to turn and offer a farewell wave in unison.
Once aboard, White House spokesman Jay Carney said, the Obamas and the Bushes dined together.
Hillary Clinton, who flew to South Africa with the Obamas and Bushes on Monday, was not on the return flight. She traveled separately with former President Bill Clinton and their daughter, Chelsea.