Jody Xiong of DDB China in conjunction with the China Environmental Protection Foundation created this wonderful outdoor campaign to create a subtle visual reminder of the environmental benefits of walking versus driving. Enormous white canvases with a bare tree were placed across 132 crosswalks in 15 Chinese cities. As pedestrians crossed their shoe soles were imprinted with a small amount of green paint, leaving behind a trail of leaf-like footprints. BBD estimated that nearly 3,920,000 people passed through the installations, and the final posters were eventually hung has billboards in several urban locations. Awesome!