The US has built its homes, schools, and hospitals so thoroughly with AC in mind that most buildings have no built-in defense against the heat at all. | Angela Weiss/AFP It was not the postcard-worthy aesthetics that prompted Greek islanders to first drench their cliffside-carved homes, churches, and pathways in a thick layer of pearly white paint.  Much like wearing a white tunic on a hot sunny day, painting your house a shade of reflective white is a fine way to keep an ancient island cool,