Tens of thousands of people are gathering in South Africa to celebrate the 100th anniversary of the African National Congress - the continent's oldest liberation movement. The party has been in power since 1994, when Nelson Mandela was elected the country's first black president. The ANC played a pivotal role in the struggle to end apartheid, and it still holds a strong majority of public support. But with in-fighting, allegations of corruption, and criticism from many sectors, there are concerns that the current party leadership is failing to live up to the titans of old.