SAN RAFAEL (CBS 5) — On this day, April 20, marijuana advocacy groups claim millions of people around the world are celebrating 420 Day, a term synonymous with smoking marijuana.

The so-called ‘high holiday’ shares an infamous date with Adolf Hitler’s birthday in 1889, and the tragic 1999 Columbine High School massacre.

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There are many myths behind the origins of the phrase 420 as slang for marijuana.

One popular myth is that 420 came about because the California police code for marijuana possession was 420. Not true.

Other untrue rumors:

— Actor/comedian Cheech Marin was born at 4:20 on April 20.

— The Grateful Dead lived at 420 Haight-Ashbury in San Francisco.

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— The Dead’s Jerry Garcia died at 4:20 a.m.

So, what’s the true story?

According to High Times magazine, 420 originated in 1971 by a group of students, known as “the Waldos,” at San Rafael High School.

The magazine said the Waldos coined the term because they would get together after school at 4:20 p.m. to smoke marijuana, and they could openly talk about 420 without anyone knowing what it meant.

High Times indicated that 420 didn’t catch on until the late 1980s when it began as an underground term circulating around Grateful Dead fans, also headquartered in San Rafael.

The term then eventually came into use in popular culture, too.

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