Cannabis culture is full of creative catchphrases and nicknames. Just look at how many names we have for our favorite plant, cannabis: weed, grass, ganja, dope, reefer, chronic, pot, bud, and that’s only to name a few. Of all of the slang and catchphrases that have been adopted by stoners, there’s one that has proved to be the most influential. That’s “420.”

The term has sparked a worldwide holiday that brings together enthusiasts around the world on April 20th, and has made 4:20 the most popular time to toke up any day of the week. But ask people where “420” came from, and you might get as many answers as there are strains of weed. But the term’s origins were traced back to an unusual adventure four decades ago in a little corner of the California Bay Area.

So, let’s explore some of the myths behind the origins of 420, and get down to the people who helped take it from a phrase used among friends to a term that has become a pivotal element of the culture.