Since the dawn of humankind, just about everything about us has changed, except for one thing: our need for sleep. Sleep is a subject that’s challenged, perplexed, and fascinated writers, poets, and scientists over the centuries. Of course, it was an abject mystery thousands of years ago, and even today, we’re not 100% sure of exactly how sleep works and why it even exists.

Harvard Medical School has developed Sleep: A Historical Perspective, an detailed interactive timeline of the impact of the subject of sleep on both science and culture.

It’s filled with lots of interesting tidbits and trivia. Did you know that but the term “circadian” (as in circadian rhythm) is only about 60 years old, even though the concept was first proposed in 1845? Did you know that Charles Dickens described sleep apnea in his writings almost years before it was officially recognized as a medical condition?

If you’re as interested in the subject of sleep as we are, or to learn more about it, we highly recommend that you take a look.