Covered bridges are an idyllic symbol of rural America. These charming, often hand-built structures have been romanticized in popular culture for years, from Thomas Kinkade’s painting “The Old Covered Bridge” to the novel (and film adaptation) The Bridges of Madison County. Despite their dispensability in the age of concrete and steel, these old wooden bridges continue to be beloved landmarks, their distinct roofs making them easily recognizable even today. But what exactly led to their...