Presidents Obama Visits Prison in South Africa

U.S. President Barack Obama visits a bleak former prison island off the coast of South Africa on Sunday to pay tribute to ailing anti-apartheid hero Nelson Mandela and set the stage for a speech urging Africans to strive for prosperity and democracy.

Obama is due to cite the legacy of Mandela, who was imprisoned on Robben Island for 18 of the 27 years he spent in jail before becoming the first black president of South Africa, in a speech at the University of Cape Town later in the day.Some protesters gathered outside the University of Cape Town ahead of Obama's speech, holding placards attacking U.S. foreign policy reading "Obama mass killer" and "End drone wars now".

The 94-year-old Mandela's faltering health has been a sombre backdrop to Obama's eight-day Africa trip. South Africa's government says his condition is "critical but stable".

Obama met Mandela's relatives In Johannesburg on Saturday to deliver a message of support instead of directly visiting the frail former president at the hospital where he has spent the last three weeks.

The U.S. leader describes Mandela as a "personal hero", and has reminded audiences in Africa in recent days that his first political activism was to urge his U.S. college to divest itself of South Africa investments to protest against apartheid.