What? Membership? Why should I become a member of Waterfall? Well appart from it being completely and totally free, you can find out why by checking out the 'Submit' link that's sneakily hidden below this annoying tool tips box.
This photo, taken by Lucas Armand Grisinelli, is one of the best submissions to the Waterfall Flickr group over the last month. See the rest of the best in our Best of Flickr 4 article and find out how to see more from the selected artists too.