Before starting his 21,000-mile journey, Paul Salopek visited Djibouti, where cairns help people navigate the desert flats during dust storms. (John Stanmeyer/National Geographic via Associated Press)

Paul Salopek has a long walk ahead of him. The 50-year-old journalist left a small Ethiopian village on foot Jan. 10, planning to retrace the steps of humans’ migration from Africa until he gets to Tierra del Fuego, at the southern tip of Chile.

The 21,000-mile journey — which will cross 30 borders and bring him in contact with dozens of languages and ethnic groups — will take Salopek seven years.

By today’s standards, that’s a long time, but the same trek took ancient humans thousands of years. When and how our ancestors dispersed out of Africa has long been controversial, though it is generally believed that they slowly spread into the Middle East about 60,000 years ago, and while some branched off and headed to Europe, others migrated eastward into Asia, crossed a land-ice bridge that once spanned the Bering Strait and traveled down the length of the Western Hemisphere.

Other than using a vessel to take him from Russia to Alaska, Salopek will mimic this epic voyage on foot. He started out in Herto Bouri, a village in Ethiopia’s Middle Awash valley, which has the longest and most continuous record of human evolution of any place on Earth. Although he’s using the past as a road map, Salopek has emphasized that his goal is to report on current global stories at a slower pace and from a different perspective than they are usually covered.

“Often the places that we fly over or drive through, they aren’t just untold stories, but they are also the connective tissues between the stories of the day,” Salopek told the Associated Press last week.

National Geographic, one of the backers of Salopek’s “Out of Eden” walk, says it will publish his dispatches from the journey. The journalist is carrying just a backpack with some camping equipment and high-tech communications gear, including a lightweight laptop and a GPS device.

Salopek told CBC Radio recently that he is planning to use some social media throughout the walk, though he won’t be microblogging. In his last tweet before starting the trip, Salopek posted a picture of his house keys.

“Existential question before a 7-year walk: Take or leave house keys?” he wrote.

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