While 420 — or April 20 — has gained notoriety as being Weed Day, many don’t know the real history behind it.

A widely held belief is that 420 is a police code that meant “Marijuana Smoking in Progress,” while some believe it is a reference to teatime in Holland or even the number of chemicals in cannabis. However, the real story is very different.

Five California teens who were athletes in their high school nicknamed themselves “the Waldos” and learned about a cannabis plant that was out in the open for anyone to take. In the fall of 1971, a Coast Guard member planted the cannabis plant but could no longer tend to the crop.

The Waldos were given a treasure map — possibly by the plant’s owner — that would lead them to the product, prompting the students to meet at the Louis Pasteur statue outside their high school at least once a week to search for the item. The time of meeting was 4:20 p.m., which was after practice since they were all athletes.

The Waldos would get in a car, smoke some pot and search the nearby Point Reyes Forest for the free plant. They “We would remind each other in the hallways we were supposed to meet up at 4:20. It originally started out 4:20-Louis, and we eventually dropped the Louis,” said one of the former students.