South African anti-apartheid activist Winnie Mandela died on Monday at the age of 81. She died in a Johannesburg hospital after long-running kidney issues. Winnie was married to anti-apartheid leader Nelson Mandela from 1958 to 1996. Nelson was imprisoned throughout most of their marriage, and Winnie's own activism led to her being imprisoned and later put under house arrest. She is seen as a major figure in South Africa's fight against apartheid.