This a (dead) tree, not a bin
So this is what I saw while walking in the narrow streets of the Barrio Gotico in Barcelona : a homemade sign on a thin tree trunk, saying “This is a (dead) tree, not a bin. Thanks”. There was also a trolley chained to it, so I admit some people actually did consider it as a garbage can.
Oh, and also : the big fish tagged in the background is made by an artist called El Pez. There is a lot of his graffitis all around Barcelona, go and google him!