Today is all about Nelson Mandela, South Africa's most famous anti-apartheid fighter and politician. Mandela spent 18 years of a life sentence in prison on Robben Island. As apartheid fell under more and more criticism, Mandela grew to become the symbol of the anti-apartheid movement. As a result, he was eventually released, going on to become an international icon. But what exactly did Mandela do? And no, he never died in prison: that's the Mandela effect.