Michelle Obama told young African leaders, including members of South Africa's post-apartheid generation, that there were more causes worth fighting for and more history to be made, urging them to be the ones who ended hunger, wiped out HIV/Aids and protected women's rights.
In an emotionally stirring speech at a Soweto church that became a popular refuge during the fight against government-imposed segregation in South Africa, America's first lady drew on the struggle for racial equality in the US and in this country as she sought to inspire young people to become the next generation of problem-solvers.
"I know that as your generation looks back on that struggle and on the many liberation movements of the past century, you may think that all the great moral struggles have already been won," Mrs Obama said in a keynote address to a US-sponsored leadership conference for more than 70 young African women.
"But while today's challenges might not always inspire the lofty rhetoric and high drama of struggles past, the injustices at hand are no less glaring. The human suffering is no less acute.
"So make no mistake about it: there are still so many causes worth sacrificing for. There is still so much history yet to be made."
Sixty per cent of Africa's population was under 25 and two-thirds of South Africans younger than 30, Mrs Obama said.
The first lady said this generation could be the one that brings prosperity to forgotten corners of the world, banishes hunger from Africa and ends HIV/Aids and the stigma associated with it.
She said they can ensure that women are no longer treated as second-class citizens, that girls get an education and that any type of violence against women is seen as a violation of human rights. "That is the history that your generation can make," she said.
She received an effusive introduction from Graca Machel, the wife of former South African president Nelson Mandela, who said Mrs Obama was the "queen of our world".
Mrs Obama delivered her 30-minute address at the Regina Mundi Church in the black township of Soweto. The church became more than a religious sanctuary 35 years ago, in June 1976, when police fired upon thousands of students who were peacefully protesting against the government's decision to require them to begin studying in Afrikaans, the language of the country's Dutch settlers.