It's not quite the Fountain of Youth, but one author spent 5 years exploring the world's "blue zones," or areas which sport unusual concentrations of long-lived people. In his new book, Dan Buettner details some keys to happy old age—including creating an environment that fosters physical activity, and having a sense of purpose.
But eating nuts five times a week can add a couple of years, too. Buettner found one "cultural" blue zone in a California town with the highest concentration of Seventh Day Adventists anywhere; they eat a Biblically-inspired vegetarian diet and keep the Sabbath. Sardinia, Italy has the most male centenarians; one 104-year-old who dispensed advice all day "started his day with a glass of wine," Buettner told NPR.