Paul Salopek is seven years into a decade long 'Out of Eden' walk, from Africa to South America.
In 2013 he set out on foot to retrace the global migration of humankind, from Ethiopia to Tierra del Fuego.
So far the journalist and National Geographic Fellow has traversed Africa to the Holy Lands, the Autumn Wars route to the Silk Road, and been through Pakistan and India. He's currently in Myanmar.
He calls his 21,000 mile (34,000 kilometres) epic trek an experiment in slow journalism.