For the past 20 years, Spanish artist Santiago Sierra’s projects have revealed, via documentary photos and videos, how global capitalism often leads to exploitation. His latest, NO, Global Tour, is a 2-hour-long video of the word “NO,” made up of 6-foot-tall letters, being carted around on a flatbed truck to various cities in Europe and the eastern U.S. The black-and-white video is oddly riveting: it swings from gritty urban areas to generic highways, periodically settling on crumbling buildings, abandoned interiors, street signs, men fishing and flocks of birds.