Our internal time, distorted as it is, may dictate a great deal of our lives, but it is external time — the scientific and cultural conventions of timekeeping — that anchors the rhythms of society. One of those most central timekeeping anchors was born on March 19, 1918, when the United States government passed the Standard Time Act — a federal law formalizing the concept of time zones. In this short animation from TED Ed, historian William Heuisler tells the fascinating story of how the railroad revolution led to the establishment of Standard Time, a seemingly simple development the impact of which profoundly shaped our everyday lives:

Complement with the curious psychology of time slows down when we’re afraid, speeds up as we age, and gets all warped when we’re on vacation, then revisit these 7 excellent books about time.