Much of public space in Mexico City has been raped. Enormous billboards are not only in your face on the inner-city highways, they hover over the main boulevards, and even in residential neighborhoods are painted on the sides of buildings or hang like banners over balconies and terraces. Others are pasted on walls hastily constructed beside empty lots.
Much of this signage is illegal, but tolerated. From time to time the city government makes a big noise about how it will soon be clamping down, but the efforts are largely limited to the expulsion of hot air. Even more occasionally the Ministry of Urban Development appears to believe that it is doing its civic by taking an action that would surely provide semiotics professors with material for at least a class: They paste large signs over the offending signs that make clear in bold type that they are there unlawfully. Thus, one eyesore partially covers another.