Where we came from is, arguably, one of the most important questions facing mankind. This week the story has become even more intriguing: the well-preserved remains of 15 individuals from a new species of human ancestor, called Homo naledi, have been unveiled by scientists in South Africa. The name means "star" in the local language and it's a nod to the rising star cave system where the remains - part of a spectacular assemblage of more than 1500 specimens - were uncovered. The finds also harbour another secret: it's possible that these individuals might have been put where the scientists... Get the references and the transcripts for this programme from the Naked Scientists website