National Geographic's new 3-part series will feature Dan Buettner, New York Times best-selling author of 'The Blue Zones: Lessons for Living Longer From the People Who've Lived the Longest' and his work. Buettner's National Geographic cover story on longevity, 'The Secrets of Living Longer' was the magazine's third best-selling issue in history. The work of Dan Buettner has bee...