Here's the backstory:
Note that the "...neutrality of this article is disputed" but generally speaking it marks the anniversary of the birth of the modern environmental movement in 1970. Interestingly enough, not all greenies enjoy the 'holiday.' Some... "Bright Greens" (http://en.wikipedia.org/wiki/Bright_green_environmentalism) apparantly think it's a bit too watered down. What i find fascinating is how there is apparantly several shades to being green! At any rate, hug a tree tomorrow and take a moment to enjoy the sun eh.