The reduction to medium of urban public space (the place with the greatest density of advertisements, after the TV screen) has given birth to many different practices of manipulation aimed at unveiling the invasions of our (fragile) sensitivity to images. The big----- EXTENDED BODY: billboards, in particular, give corporations the possibility to place, for some time, copious static stimuli in the eyes of a large part of the population. The artistic intervention on these spaces (already studied and put into perspective in the book ' Billboard: Art on the Road') is used by the Billboard Liberation Front Creative Group to spectacularly and effectively challenge the deceiving culture of mass advertising. With an impeccable production made of fonts and backgrounds identical to the original ones, not to mention the 'physical' interventions, such as the nightmarish statue for McDonald's ("To Serve Man"), the anonymous group of saboteurs challenges the paper outposts of corporations by retouching their fundamental slogans and reopening in an unforgiving subliminal way the huge and hidden social wounds of the USA.