By now, you don’t have to be a smoker to know that April 20 is considered by many to be a sort of national holiday for cannabis culture. Some have suggested that the date comes from “420” being a code among police officers for “marijuana-smoking in progress,” while others say that there’s a connection to 4/20 being Nazi dictator Adolf Hitler’s birthday. But the most credible story about why 4/20 is a thing involves neither of those ideas. Instead, it involves five high school students who, back in 1971, would get together at 4:20 p.m. to smoke marijuana by a statue of chemist Louis Pasteur at San Rafael High School in Marin County, Calif. Known as the “Waldos” — Steve Capper, Dave Reddix, Jeffrey Noel, Larry Schwartz, and Mark Gravich — they would say “420” to each other at some point during the school day as code to meet for a smoke.
Reddix’s brother helped him get a job as a roadie for Grateful Dead bassist Phil Lesh, and the term “420” caught on in that Deadhead circle. The legend goes that on Dec. 28, 1990, Deadheads in Oakland handed out flyers inviting people to smoke “420” on April 20 at 4:20 p.m — and one got in the hands of Steve Bloom, a former reporter for High Times magazine. The publication published the flyer in 1991 and continued to reference the number, and before long those digits became known globally for their association with marijuana. In 1998, the outlet recognized the “Waldos” as the “inventors” of 420.
The Waldos still live in northern California, in Marin County and Sonoma County, and are still good friends. TIME caught up with Reddix, now a documentary filmmaker and former CNN cameraman, and Capper, who runs a business that works with staffing agencies, to learn more about 4/20 history.
The reasons for their meeting time, it turns out, aren’t very complicated: school ended around 3:00 p.m., and then came sports practice, and then it would be about 4:20. And the social circumstances that led to the ritual might be familiar to any number of high-schoolers.
“We got tired of the Friday-night football scene with all of the jocks,” says Reddix. “We were the guys sitting under the stands smoking a doobie, wondering what we were doing there.”