This Sunday is Earth Day - an annual, international celebration of environmental awareness. It began in 1970 in the era of hippies and "flower power," and some consider it the "birthday" of modern environmentalism.
Ray Bradbury didn't invent the phrase "Butterfly Effect," but in 1952 he used it in the seminal science fiction story, "A Sound of Thunder." In his story, time travelers visit prehistoric times, taking great care to alter nothing. But one traveler accidentally steps on a prehistoric butterfly, creating a ripple effect that changes modern history for the worse.