Walking is falling forward.
Each step we take is an arrested plunge, a collapse averted, a disaster braked. In this way, to walk becomes an act of faith. We perform it daily: a two-beat miracle—an iambic teetering, a holding on and letting go. For the next seven years I will plummet across the world.
I am on a journey. I am in pursuit of an idea, a story, a chimera, perhaps a folly. I am chasing ghosts. Starting in humanity’s birthplace in the Great Rift Valley of East Africa, I am retracing, on foot, the pathways of the ancestors who first discovered the Earth at least 60,000 years ago. This remains by far our greatest voyage. Not because it delivered us the planet. No. But because the early Homo sapiens who first roamed beyond the mother continent—these pioneer nomads numbered, in total, as few as a couple of hundred people—also bequeathed us the subtlest qualities we now associate with being fully human: complex language, abstract thinking, a compulsion to make art, a genius for technological innovation, and the continuum of today’s many races. We know so little about them. They straddled the strait called Bab el Mandeb—the “gate of grief” that cleaves Africa from Arabia—and then exploded, in just 2,500 generations, a geological heartbeat, to the remotest habitable fringe of the globe.