His findings—along with easy steps you can take to live more like these cultures—can be found in his book, The Blue Zones Secrets for Living Longer: Lessons From the Healthiest Places on Earth.

From true tales in national parks to futuristic stories set in the world’s largest ocean, these books touch on travel in new and, at times, surprising ways.

These exclusive National Geographic Day Tours are now available for booking across all Celestyal itineraries that include Athens, Dubrovnik and Rhodes. The program exemplifies how modern cruise ...