While today most of the world will be celebrating the resurrection of Christ, today is another landmark for another reason. See how in Denver, Colorado how weed culture has taken over everything from vending machines to even the front page of the Denver Post. For native Californians, 4/20 Day has become an unofficial holiday of sorts, further pushing the “live and let live” mantra that seems to be largely associated with the Golden State. Of course, counter culture originated from the West and now we’re here to determine how exactly we’ve come to celebrate the biggest weed holiday of the year.

The rumors are both hilarious as they are creative; with everything from Hitler’s birthday (April 20, 1889) to an alleged code used amongst police officers being linked to it. Yet the truth, as usual, is often less colorful than the myth.

It’s actually been traced back to the early 70s, coined by a group of San Rafael teenagers known as the Waldos. The group chose 4:20 (as class ended at 3pm) as the designated time to meet up and smoke. It would later transform into a code word in itself, as they began to use the term while out searching for a marijuana field that they had been tipped off about as being abandoned.

The goal? To score free weed and smoke it amongst friends; and 4-20 was born.

Explained one of the Waldo brothers to the Huffington Post in 2010, “I could say to one of my friends, I’d go, 420, and it was telepathic. He would know if I was saying, ‘Hey, do you wanna go smoke some?’ Or, ‘Do you have any?’ Or, ‘Are you stoned right now?’ It was kind of telepathic just from the way you said it,” Steve says. “Our teachers didn’t know what we were talking about. Our parents didn’t know what we were talking about.”

From there the term began to loosely float among the Cannabis Culture; eventually gaining mainstream recognition after one of the Waldo’s members introduced the term to the Grateful Dead, who they knew via a family member.

Once reaching Dead Heads, as fans of the iconic group are known as; it began to reach national consciousness, serving as a perfect vehicle for the Hippie Culture which peaked within the Bay Area during the 70s. Since then the term has floated across the country, migrating from UC campuses to festivals thousands of miles away.

With the passing of legislation in Washington and Colorado formally legalizing the use of the drug, at least on a state level, the “holiday” continues to grow and enjoy support. While it may never catch on amongst mainstream society, for proponents of legalizing marijuana it remains a celebration in itself.

Also, we’ll never know if Dominos will bring back its legendary 4/20 deal.