Security guards and volunteers stand outside the First National Bank (FNB) Stadium, also known as Soccer City, ahead of Nelson Mandela's national memorial service on Tuesday in Johannesburg December 9, 2013. More than 70 world leaders from U.S. President Barack Obama to Iran's Hassan Rouhani are flying to South Africa for events commemorating Nelson Mandela this week, an unprecedented gathering that will hail one of humanity's great peacemakers. The 95,000-seat stadium in Soweto, the township that was at the heart of the anti-apartheid struggle, will host the main memorial ceremony for Mandela, who died on Thursday aged 95.SIPHIWE SIBEKO/Reuters