Referring to the consumption of cannabis, the slang term 420 has evolved into the international holiday, Weed Day, celebrated on April 20 when pot smokers congregate to consume and celebrate cannabis.
While some events are political, advocating the decriminalization of medicinal marijuana, others are just an excuse to bring people together for a party. The origin of the term is widely debated.
Some say it's the number of chemicals in cannabis, others point to a flier at a Grateful Dead concert calling for a smoke-out on 4/20 at 4:20 pm while others claim it stems from the police code 420 supposedly meaning a marijuana use in progress.
The most common belief is that a group of San Rafael high school students called the Waldos met at 4:20 in p.m. to search for an abandoned cannabis crop back in 1971.
The term officially entered mainstream culture in 2003, when the California Legislature named the medical marijuana bill SB420. Consequently, marijuana dispensaries have been a hot topic in Los Angeles ever since they began to crop up faster than Starbucks.