Obama Ends Africa Trip

U.S. President Barack Obama heads a soccer ball at Ubungo Power Plant in Dar es Salaam, July 2, 2013. The ball called a "soccket ball" has internal electronics that allows it to generate and store electricity that can power small devices.

U.S. First lady Michelle Obama walks with Salma Kikwete, wife of Tanzania's president, during a departure ceremony in Dar es Salaam, July 2, 2013.

U.S. President Barack Obama and former president George W. Bush (left) attend a memorial for the victims of the 1998 U.S. embassy bombing in Dar es Salaam, July 2, 2013.

U.S. President Barack Obama, first lady Michelle Obama, Tanzanian President Jakaya Kikwete, and Tanzanian first lady Salma Kikwete wave as they arrive at State House in Dar es Salaam, Tanzania, July 1, 2013.

President Barack Obama and Tanzanian President Jakaya Kikwete walk in front of Michelle Obama and Salma Kikwete as they arrive at the State House in Dar es Salaam, Tanzania, July 1, 2013.

Young girls and women wear the khanga, a traditional wrap, with the image of U.S. President Barack Obama as they line up to greet him at the State House, in Dar es Salaam, Tanzania, July 1, 2013.

U.S. President Barack Obama writes in a guest book as he tours Robben Island with first lady Michelle Obama, near Cape Town, June 30, 2013.

U.S. President Barack Obama departs the Robben Island prison cell where Nelson Mandela spent 18 of his 27 years of imprisonment near Cape Town, June 30, 2013.

U.S. President Barack Obama listens to Desmond Tutu as he visits his HIV Foundation Youth Center and takes part in a health event in Cape Town, June 30, 2013.

U.S. President Barack Obama greets participants at a town hall-style meeting with young African leaders at the University of Johannesburg in Soweto, June 29, 2013.

Members of the White House traveling staff walk to a group of helicopters about to transport U.S. President Barack Obama from a soccer field in Johannesburg, June 29, 2013.

Protesters argue with police outside the University of Johannesburg in Soweto, ahead of a visit by U.S. President Barack Obama, June 29, 2013.

U.S. President Barack Obama and first lady Michelle Obama look out of a doorway that slaves departed from on Goree Island, Senegal, June 27, 2013.

U.S. President Barack Obama visits a food security expo in Dakar, Senegal, June 28, 2013.

People line the motorcade route of U.S. President Barack Obama on his way to meet with Senegalese President Macky Sall in Dakar, June 27, 2013.