Greater Boston subway riders will see a frame-by-frame animation ad from the windows of Red Line trains as they travel.
400 still images have been placed on a 1,000-foot stretch of tunnel wall, between two important stations. Timed so riders see 24 images per second, lights flash on and off as a train passes, transforming the images into a moving montage of cruise-goers snorkeling, jet-skiing, and rock-climbing aboard a Royal Caribbean ship.
The ad technology first appeared three years ago in Atlanta, Budapest, and Kuala Lumpur, Malaysia, then spread to cities like Tokyo and Hong Kong. They have also been seen in trains running between New York City and New Jersey.
The Royal Caribbean ad will run through September, after which another advertiser will take its place.
Picture is a frame-by-frame animation from Muybridge.