Brazil's Banksies

Brazil has its own Banksies. One of them is Zezao, who paints his graffiti in the slums and sewers of Sao Paulo. Another is Titifreak, who spreads his graffiti as far as he can. Sao Paulo's Museum of Contemporary Art is showing their work. Gary Duffy in Brazil tells the story for BBC News, with more pictures and links to their websites.