I live in Sao Paulo, Brazil, where we have a very strong repression by the city administration against any kind of street art. In a city fulled with misery, heavy car traffic, hunger, people living in the streets, gray and dirt all around, millions of dollars are being spent yearly to erase or paint in gray any kind of public artistic manifestation on walls, not only on public places but also on private walls.
On sunday, september 13, about 200 people took over a very popular avenue, called 23 de maio, with a very wide range of public artistic intervention: grafffiti, pixaçao, sticker, posters, stencils, photo, videoart, street poetry, etc., as a way of protesting against the policy of erasing all the city walls. 9 of the artists were taken to jail (as you can see in the video linked below) and some hours later were released with no charges, only beacuse there was some press covering the action. All the art seen on the video, which is only a part of the whole intervention, was painted/done in about 5 hours that morning. At night on the same day the works were being erased, and there are no works left today.
Here's the video:
Some more pictures: