A monarch butterfly (Dannaux plexippus) flaps its wings in Piedra Herrada Sanctuary, Mexico. Might this start a chain of events that results in a tornado in Texas? Photograph by Jaime Rojo In 1961, ...

It’s always fun to hear about magical coincidences and serendipitous moments, like when someone decides to take a last-minute road trip and ends up meeting the love of their life. On TikTok, many ...

Is the 2004 Ashton Kutcher vehicle The Butterfly Effect a good movie? Definitely not, no—but try telling that to me at age thirteen. And then wrap your head, once more, around the fact that if you had ...