How do you get cars to slow down for pedestrians? Grab drivers’ attention with a “floating” crosswalk like this one in Iceland. Officials in Ísafjör∂ur (EES-uh-fyor-der) didn’t want to install traditional speed bumps, which can increase air pollution when cars struggle to get over the raised asphalt at slow speeds. So they created this optical illusion instead. The crosswalk is painted using colors and shadows to create depth, so that it appears to be hovering in the air.