Cairns have decorated the landscapes of cultures throughout time. Piles of stone-one stone placed on top of another-are set in place all over the earth to recall battles, identify burial sites, mark trails, and spur hearts and minds to remember sacred, noble, and critical events. They are landmarks. They are sacramental presences in space and time. Our lives are littered with markers of meaning. They all reveal who we are, where we have been, and...