The 20th of April (420 in the American calendar), has spread around the world as a number to signify cannabis. What started with an almost arbitrary time to meet up for a toke, became one of the strongest memes for cannabis. A code, a time, and a date.

The term was coined in 1971 by a group of five San Rafael High School friends, who called themselves ‘the Waldos’ because they met up by a wall just outside the school, at 4:20.

New generations put their own spin on it, but the core of the meaning remains: time to celebrate cannabis with friends and relax.