"They are called Blue Zones because when Buettner and his colleagues were searching for these areas, they drew blue circles around them on a map." [1] [1] http

"They are called Blue Zones because when Buettner and his colleagues were searching for these areas, they drew blue circles around them on a map." [1] [1] https://www.healthline.com/nutrition/blue-zones https://www.healthline.com/nutrition/blue-zones