FOR HISTORY NERDS, activists, and rabble-rousers, Signs of Change is overwhelming. More than 600 posters and 100 photos cover the walls of Pacific Northwest College of Art's main campus building, stretching high above students' heads. Hand-printed, '80s-era anti-apartheid T-shirts hang from the ceiling, photos of American Indians on Alcatraz Island in 1969 fill a gallery wall, current anti-car posters spread across a wall near the door. Where to start?

Dara Greenwald and Josh MacPhee of the Justseeds artists collective spent two years pulling together this immense and inspiring collection of art from international social movements from 1960 to the present. From pro-choice activists in the United States to South African screenprinters who were executed for spreading anti-apartheid messages, the posters and historic ephemera show how counterculture groups used lo-fi media to create movements and influence mainstream thought.

Signs of Change launched in New York in September 2008 and is touching down in Portland as it moves between galleries around the country. It's refreshing to see the collection of rare political posters and photographs hanging in a gallery as art, rather than wedged into the pages of a dense academic book. On their blog at justseeds.org, Greenwald and MacPhee note that although social movements have been thoroughly discussed and dissected in writing, no one has yet "chronicle[d] the artistic and cultural production of these movements." It's about damn time.