It may have seemed like good news when federal officials announced earlier this month that U.S. life expectancy had jumped four months and, for the first time, surpassed 78 years.

But forget about 78. What if someone said that you--not some future generation--should be able to live into your 90s in relatively good health?

In Pictures: The World's Longevity Secrets

That's the premise behind a new National Geographic book, The Blue Zones: Lessons for Living Longer from the People Who've Lived the Longest. Partially funded by the National Institute on Aging, explorer Dan Buettner and a team of researchers identified four geographic regions where small groups of people are living particularly long, healthy lives. Blue zones refer to the concentric circles Buettner and his team drew on a world map in blue ink to demarcate the areas with the highest life expectancies, including the Barbagia region of Sardinia, Italy; Okinawa, Japan; the community of Seventh Day Adventists in Loma Linda, Calif.; and the Nicoya Peninsula in Costa Rica.   Read More...