COVER—Pasquale Sorrentino; 1—NARA; RG 127; 3—(clockwise from top left) Otto Botticher, Union Prisoners at Salisbury, N, C., 1863. Courtesy of Reynolda House Museum of American Art, Affiliated with Wake Forest University, Courtesy Brent Woodfill, © Denis Gliksman/INRAP, Courtesy Mozas-Calvache Antonio Tomása, Courtesy William Keegan/Florida Musem; 4—Azoor Photo Collection/Alamy Stock Photo; 6—Wikimedia Commons; 9—Courtesy David Frayer/University of Kansas; 10—Tim Whitby/Alamy Stock Photo; 12—Courtesy of Shumla Archaeological Research and Education Center, Courtesy Elanor M. Sonderman, Tee-roy/Istock by Getty Images, © Denis Gliksman/INRAP (2); 13—Courtesy Julie Schablitsky/Maryland Department of Transportation; 14—Courtesy Vasant Shinde, ImagineChina; 16—Courtesy Brent Woodfill (2), Courtesy William Keegan/Florida Museum (2); 17—Photo Marquita Volken/© Office of Culture and Gentle Craft; 18—Illustration: Otto Botticher, Union Prisoners at Salisbury, N, C., 1863. Courtesy of Reynolda House Museum of American Art, Affiliated with Wake…