Many thought that the time for field exploration in the search for human origins was over. Then in 2013, paleoanthropologist and National Geographic Explorer-In-Residence Lee Berger made a remarkable discovery: While exploring the Rising Star cave system in South Africa, his team stumbled upon one of the greatest fossil discoveries in the past half century.

They found a new species of human ancestor that could very well change the way we think about human ancestry and evolution.

In part one, Berger talks about the circumstances and passion that drove him to make this incredible find and the cavers who saw it first.

(National Geographic)