People start singing as they arrive for a mass memorial for late former South African President Nelson Mandela at First National Bank (FNB) Stadium, also known as Soccer City, in Johannesburg December 10, 2013. World leaders, from U.S. President Barack Obama to Cuba’s Raul Castro, will pay homage to Mandela at the memorial that will recall his gift for bringing enemies together across political and racial divides. REUTERS/Kai Pfaffenbach (SOUTH AFRICA – Tags: POLITICS SOCIETY OBITUARY) – RTX16BTU