Whether you're a fan of his legacy, or not, Barack Obama is one of the world's great living orators. Today, he is giving the keynote speech at South Africa's celebration of the late great Nelson Mandela's 100th birthday. Tune in above to see what Obama has to say about Mandela's legacy as well as the topics of the day like immigration, nationalism and economics.

Read our take on how people abuse Mandela's legacy here.

Understandably, social media is ablaze with commentary. See some of the best below:

Many people are blown away by Obama's on-stage charisma:

While many are also critical of Obama's legacy as president:

Many South Africans are watching how their own problematic politicians react to Obama's message:

Most are taking great inspiration from many of his points: