Out of Eden Walk: Walking through unknown Pakistan

The feudal principalities of far northern Pakistan - home to walled villages, yak herders, glacial rivers, golden poplar forests and snow leopards - held off, or played off, would-be conquerors ranging from Alexander the Great to imperial Great Britain. Host Carolyn Beeler speaks with National Geographic Explorer Paul Salopek, whose globe-spanning journey on foot brought him through this remote region that is on the cusp of change.