Via the Princeton University Library, this stunning gallery of contemporary protest artwork from The Asamblea de Artistas Revolucionarios de Oaxaca (Assembly of Revolutionary Artists of Oaxaca or ASARO), which evolved from the 2006 Oaxaca teachers' strike and the subsequent violence:
ASARO formed as a collective, no individual artist's names are used, working in a variety of mediums to commemorate public actions and critique political responses. For instance, the print above documents the army's use of helicopters to drop chemicals on peaceful protesters. Graphic Arts has acquired forty-nine woodcuts, stencils, and poster by ASARO, many as large as 100 x 70 cm.
More prints and street art images on the ASARO blog (via Bibliodyssey).