By the banks of the Congaree River in Columbia, South Carolina, four squat brick kilns sit in a neat row on an unfenced, open lot. Wrapped in rusted metal bands, with patches of moss and wild grass emerging from their domed roofs, it’s evident their days of function are long gone—a point further underlined by the shiny new apartment complex next door. When it comes to urban development, however, these kilns have actually overpaid their dues: they’re all that remains of a 19th-century brick-making empire responsible for much of the…