How did 4/20 become 4/20? It has nothing to do with police codes, Bob Marley’s death, or Hitler’s birthday. It’s not teatime in Holland, related to California’s penal code, or the number of chemical compounds in marijuana. It does have something to do with the Grateful Dead, but not in the way you’ve probably heard.
Take a trip in the video above to San Rafael, California, in the fall of 1971, for the actual story, which is much better than any of the myths.
Update, April 21, 2015: This video has been updated to reflect the local pronunciation of San Rafael, Marin County, and Point Reyes.