The Obamas departed Africa for home shortly after crossing paths with the Bushes, who were hosting the summit promoting the role of African first ladies in bringing change to their countries. Bush ended up joining the current president for the wreath-laying ceremony honoring the Tanzanian victims of the simultaneous attacks at the U.S. embassies here and in Kenya masterminded by Osama bin Laden.
Both presidents have bin Laden in common. Bush's two terms were tinged by the 9/11 terrorist attacks carried out in New York and Washington by bin Laden's al-Qaida network; Obama ordered the U.S. military raid that ended with bin Laden' death two years ago in Pakistan.
Obama and Bush bowed their heads as a Marine placed the wreath of red, white and blue flowers in front of the large stone memorial on the grounds of the new U.S. Embassy. After a few moments, they shook hands with survivors of the attack and relatives of those killed before returning to the embassy together in private discussion.
At that very moment, their wives were putting on a public display of mutual affection in a discussion moderated by American journalist Cokie Roberts. Mrs. Obama said she wanted to appear with Laura Bush because "I like this woman" and it's therapeutic to share the challenges of their roles.
"It's sort of a club, a sorority, I guess," Mrs. Bush responded.
Their goal was to encourage African first ladies to raise their voices for causes they are passionate about, even if the public is sometimes focused on more trivial matters, the said.
"While people are sort of sorting through our shoes and our hair, whether we cut it or not ..." Mrs. Obama started.
"Whether we have bangs," Mrs. Bush interjected to laughter. Mrs. Obama expressed surprise that her change in hair style this year would prompt so much media coverage. "Who would have thought? I didn't call that."
"But," Mrs. Obama said, "we take our bangs and we stand in front of important things that the world needs to see. And eventually people stop looking at the bangs and they start looking at what we're standing in front of."
"We hope," Mrs. Bush joked. Mrs. Obama replied, "They do, and that's the power of our roles."
When it comes to the power of their husbands' roles, Obama has said he wants to usher in a new era of U.S.-Africa relations. Obama has praised Bush for helping save millions of lives by funding AIDS treatment. But, he said Monday, "We are looking at a new model that's based not just on aid and assistance, but on trade and partnership."
"Ultimately, the goal here is for Africa to build Africa for Africans," Obama said. "And our job is to be a partner in that process."
In that spirit, Obama announced a program to bring more power to Africans without access to electricity. During a visit to a local power plant built with a U.S. grant, Obama demonstrated a soccer ball designed to bring power to communities off the power grid.
One invention that could help on the electricity front is the SOCCKET ball, developed by two Harvard graduates. The ball has a pendulum-like mechanism inside that creates kinetic energy during play and stores it. Its maker says 30 minutes of play can power a simple LED lamp for three hours.
Obama kicked the ball off his foot and did a low header. "We're going to start getting these all around Africa," Obama said. "Pretty impressive stuff."
In remarks afterward, he touted his "Power Africa" electricity program as a win-win for Africans and U.S. companies. He also reflected on the trip, recalling some of the folks he met along the way, including a female farmer in Senegal and young people in the Soweto area of South Africa's capital city, Johannesburg.
"I'm inspired because I'm absolutely convinced that with the right approach, Africa and its people can unleash a new era of prosperity," Obama said.
AP White House Correspondent Julie Pace contributed to this report.