special correspondent sophia kruz of detroit public television has our report. ♪ >> reporter: in brazilhe start of the 2014 world cup was cause for celebration, but amidst the partying was also protests, with many brazilians speaking out against the $11 billion their country spent on the games. $11 billion, they say, they could have been spent building desperately needed schools and hospitals instead of football stadiums. but the protests haven't all been violent and one of the peaceful weapons is public art. this anthropologist explains. >> these are weapons that people who have no formal political power can employ and they have been things like samba, music, humor and graffiti fits right in there. >> reporter: graffiti is used as a powerful tool for political protests in urban areas around the world, by in rio de janeiro, it's more than that. here it's woven into the fabric of the urban landscape, bold in scale, often stretching city blocks, and every inch is legal thanks to a federal law decriminalizing street art in 2009, which has been great for graffiti artists like berno. >> they