Near where I work, I have noticed several times shoes hanging on a wire. They seem to disappear and re appear from time to time. I finally managed to took a picture to show you this strange thing (please, have a look a the picture below, please, thanks). As all the shoes seem to be white, I thought it was a trick used by secondary school kids not to have to attend sport lessons.

I talked to an Irish guy, and it seems to be a known phenomenon all over Dublin, probably an urban legend. It occurs in flats neighborhoods and it is supposed to mean that drug can be sold or bought in the area.