U.S. first lady Michelle Obama waves to the audience during a youth event at the Sci-Bono Discovery Centre, Saturday, June 29, 2013, in Johannesburg, South Africa, organized in conjunction with MTV Base, an African youth and music TV channel, and Google+ to highlight the importance of education. (AP Photo/Carolyn Kaster)

Photo by: Carolyn Kaster

U.S. first lady Michelle Obama waves to the audience during a youth event at the Sci-Bono Discovery Centre, Saturday, June 29, 2013, in Johannesburg, South Africa, organized in conjunction with MTV Base, an African youth and music TV channel, and Google+ to highlight the importance of education. (AP Photo/Carolyn Kaster)