Out of the many ideas of the origins of 420, one even including Hitler’s birthday, there’s only one true story.
The most credible story traces 4/20 to Marin County, Calif. In 1971, five students at San Rafael High School would meet at 4:20 p.m. by the campus’ statue of chemist Louis Pasteur to partake. They chose that specific time because extracurricular activities had usually ended by then. This group — Steve Capper, Dave Reddix, Jeffrey Noel, Larry Schwartz, and Mark Gravich — became known as the “Waldos” because they met at a wall. They would say “420” to each other as code for marijuana.
As Reddix told TIME in 2017, “We got tired of the Friday-night football scene with all of the jocks. We were the guys sitting under the stands smoking a doobie, wondering what we were doing there.”
Later, Reddix’s brother helped him get work with Grateful Dead bassist Phil Lesh as a roadie, so the band is said to have helped popularize the term “420.”
The term “420” was widely in use by the end of the 1970s. Deadheads spread it outward like a virus from their San Rafael ground zero. Within a decade, pot smokers were using it across the country and around the world. High Times started using the term “420” as early as 1990, and later bought the website 420.com, which includes videos, news, horticulture tips, and activism.
Pop culture is filled with references to 420. The clocks and timepieces in Pulp Fiction and later in Lost in Translation are all set to 420. And is it an accident that the score on the football scoreboard in stoner classic Fast Times at Ridgemont High reads 42-0?
While many other illicit tales of the origins of 420 have wafted into the half-baked history books, the Waldos have proof they used the word back in the 70s. Kept safely tucked away in a vault in a San Francisco bank is their original 420 tie-dyed flag, a newspaper clipping where one of the members discusses wanting to just say “420” for his high school graduation speech and postmarked letters between the group filled with 420 references.
What are you going to do to celebrate the holiday this year?