You've probably heard a lot of stories about where the 420 phenomenon got its start. Despite what your college roommate told you, it has nothing to do with police codes, Bob Marley, or Adolf Hitler's birthday (talk about a buzzkill).

Thanks to a history lesson from Slate, we can finally clear up the myth once and for all. Turns out 420 found its roots in the Bay Area in 1971. The story goes that a group of San Rafael teens, known as the Waldos, would regularly meet at a statue on their high school campus at 4:20pm, before heading off to Point Reyes in search of an alleged field of pot. Despite weeks of searching, they never found it, but they did find themselves unwittingly changing the history of popular culture, thanks to a connection within the Grateful Dead, who made the phrase go from local shorthand to a global movement.

Click below to watch the story unfold (and hear the narrator pronounce Marin wrong):