How did the human race populate the world? A group of geneticists have worked on the question for a decade, arriving at a startling conclusion: the "global family tree" can be traced to one African man who lived 60,000 years ago. Dr. Spencer Wells hosts this innovative series, featuring commentary by expert scientists, historians, archaeologists, and anthropologists.

"Take an in-depth look at some of nature's most terrifying scenarios. Perfect disaster examines six possible catastrophes that may result in unprecedented destruction. From a mega-sized tornado measuring two miles across, to a solar wind that could cause a worldwide blackout -- these "perfect" storms give little notice before their devastating results. See how cities such as Dallas could be reduced to rubble in a few minutes, and why London may be...