A digital signage system including a first display device; a second display device arranged a first spatial interval from the first display device and having a display screen that at least partially overlaps a display screen on the first display device; and a controller configured to control the first display device to display single image data at a first time, and control the second display device to display the single image data at a second time based on the first spatial interval between the first display device and the second display device. Further, at least one of the first display device and the second display device is a transparent display.