Mendota Stoppages, 1969-1974
These series of demonstrations on the outskirts of Ocean Park, California proved that light could be used to direct not just the external experience of the viewer, but also internal phenomena and the absence of stimulus. Turrell spent two years sealing off an abandoned hotel and making every surface in each room perfectly smooth. Then he would direct diagonal beams of light around the darkened rooms. Near the end of one performance for an audience, he completely obliterated the light source. However, audience members insisted they still saw light beams. There were none.