An artist’s rendition of Camp Parole, Maryland. This camp housed Union prisoners awaiting exchange. Photo courtesy of Library of Congress.

Professor Francis Lieber, author of the Lieber Code. Photo courtesy of Library of Congress.

The exterior of Libby Prison, Richmond, Virginia. This picture was taken in 1865, after Union troops captured the city. Photo courtesy of National Archives, Brady Collection.

Old Capitol Prison, Washington, D.C. Photo courtesy of National Archives, Brady Collection.

This emaciated prisoner survived captivity at Andersonville. Photo courtesy of Library of Congress.

Winslow Homer’s Near Andersonville. Photo courtesy of the Newark Museum.

The front entrance of the National Prisoner of War Museum, Andersonville, Georgia. Photo courtesy of Andersonville National Historic Site.

Artifacts discovered at Andersonville Prison. Photo courtesy of National Archives, Brady Collection.

Remnants of the Andersonville stockade and trenches, late nineteenth century. Photo courtesy of National Archives, Brady Collection.

The exterior of Castle Thunder, Richmond, Virginia. Photo courtesy of National Archives, Brady Collection.

Major General Henry W. Halleck, Chief of Staff of the Union Army. Photo courtesy of Library of Congress.

The hanging body of Captain Henry Wirz. This photo was taken immediately after Wirz’s execution. Photo courtesy of Library of Congress.