What do the Point Reyes lighthouse, French chemist Louis Pasteur and the Grateful Dead all have in common? Well, they’re all part of the origin story of how 420 methodically worked its way from a secret code to mainstream weed lingo.

In 1971, five San Rafael High School students were tired of Friday night football games and searching for parties. The five students called themselves the “Waldos,” referencing the wall they would sit on at their school. The wall, located in the main courtyard in front of the cafeteria, was the perfect spot for the Waldos to work on impressions of their fellow classmates and teachers.

They began occupying their time with adventures called “safaris,” after Steve Capper took them to what is now Silicon Valley in search of a holographic city that he read about in Rolling Stone. Safaris were a way for the Waldos to challenge one another to come up with something out of the box to do. Most took place in the Bay Area, but sometimes they traveled farther afield in California. There were two rules to safaris: They had to go somewhere new, and participants had to be stoned.

One day, the Waldos met at 4:20 p.m. for a “safari” and smoked all the Panama Red and Acapulco Gold — marijuana strains popular at the time for their potency and energizing qualities — they could get their hands on. [Read More @ LA Times]