Thirty million footsteps

Across 21 thousand miles, over seven years, the double Pulitzer Prize winning writer and National Geographic Fellow Paul Salopek is on a journey that will take 30 million footsteps. He's walking the world, from Africa to Tierra Del Fuego following the paths of the human beings who set off on the first and greatest voyage of sentient discovery, the ancient migration across the planet that started 60,000 years ago.