Modern life makes us tired, right? But research from societies in Africa and South America suggests people in the ancient world slept only 6.5 hours a night.

Modern life makes us tired, right? But research from societies in Africa and South America suggests people in the ancient ...

China's 24 Solar Terms, the ancient Chinese knowledge of dividing a year through the observation of the sun's annual motion, was inscribed on the World Intangible Cultural Heritage List in 2016.