British artist James Bridle is fascinated by surveillance technology. Once, he photographed 140 CCTV cameras on the walk between his London flat and the tube. This past year, he installed a white surveillance balloon above an abandoned East London parking lot. So it made sense that when Bridle was asked to host an online artist's residency, he planned a 12-mile stroll around London's central district to take stock of all the cameras that analyze car license plates.