Why is 420 weed day?

Could you please elaborate on the origins and significance of "420 weed day"? Is it a cultural phenomenon rooted in a specific historical event or simply a numerical coincidence that has gained popularity over time? Are there any particular traditions or rituals associated with this day? How does it impact the cryptocurrency and finance world, if at all? I'm curious to learn more about its background and why it holds such importance for many people.