Mandela's body is lying in state in a glass-topped coffin. Mourners will have three days to pay their final respects.
As four junior naval officers in white uniforms kept watch, leaders including Zimbabwe President Robert Mugabe and South African President Jacob Zuma passed by the casket in two lines. Celebrities like singer Bono of the band U2 also paid their respects. F.W. de Klerk, the last president of white rule who shared a Nobel Peace Prize with Mandela for ending the apartheid era, was also at the viewing.
"My thought now is that I hope that his focus on lasting reconciliation will live and bloom in South Africa," de Klerk later said.
Earlier in the day, many lined the streets as Mandela's flag-draped coffin was carried through Pretoria, into the Union Buildings, the seat of South African power and the place where Mandela served as president almost 20 years ago.
Each day Mandela's coffin will be driven back to 1 Military Hospital to be held overnight. Authorities have asked the public to line the street as an honor guard for each trip.
Mandela's body will lie in state through Friday before his burial Sunday in the town of Qunu, where he grew up.
This all follows Tuesday's massive memorial where 91 world leaders joined thousands of South Africans to honor Mandela. There is some controversy surrounding the interpreter who was hired for the event. Members of the hearing impaired community in South Africa claim the man's sign language made no sense and that he is a fraud.
The South African government is expected to issue a statement regarding the complaints, many of which came from social media.
The Associated Press contributed to this report.