As the "third pillar" of health, as some might call it, (along with nutrition and exercise) sleep is a fundamental ingredient for healthy living.
There is still a lot of research and unanswered questions going around this intricate topic, after all, who isn't intrigued by the purpose of unconscious hours spent dreaming under the duvet every night?
From a giraffe's ideal number of ZZZs to Mariah Carey's performing power after catching 40 winks, here's everything you've ever wanted to know about sleep.
30 Facts About Sleep [Infographic] by the team at Sleepys