The week-long farewell to Nelson Mandela is underway in South Africa.

Monday morning, President Barack Obama and First Lady Michelle Obama departed Washington for Johannesburg on Air Force One.

They were joined by former President George W. Bush and his wife Laura and former Secretary of State Hillary Clinton.

In an exclusive interview with the BBC, Mandela's oldest daughter Makaziwe Mandela described her father's last moment.

"The children were there the grandchildren were there, Graca was there, so we were always around him and even at the last moment we were sitting with him," said Makaziwe.

Nearly 100 world leaders including Pope Francis will join 90,000 South Africans to pay their respects to the man who healed a nation and changed history.