Cape Girardeau’s Fort D, Missouri’s only surviving V-shaped, Civil War-era earthworks, has been named to the National Register of Historic Places. Associate director of the Cape Girardeau Research Center of the State Historical Society of Missouri. Cape Girardeau has more than 30 national register sites and nine historic districts. The site is significant as part of Cape Girardeau’s Civil War history. It was one of four forts built by the Union Army to protect Cape Girardeau. It is the only fort remaining in Cape Girardeau and the only surviving earthworks of all the forts that were built to protect Missouri’s major cities.