Last year marked the 150th anniversary of the start of the American Civil War, a milestone commemorated by The Atlantic in a special issue (now available online). Although photography was still in its infancy, war correspondents produced thousands of images, bringing the harsh realities of the frontlines to those on the home front in a new and visceral way. Photographers also made extensive use of stereo photography, bringing images to the public in three dimensions, for those with access to a stereoscopic viewer. The images collected here are stereo pairs, which will animate when clicked (starting with photo #2), adding a new dimension, and further bringing home the reality of the moment. (Be sure to see part 1 and part 2 as well.) Keep in mind, as you view these photographs, that they were taken 150 years ago -- providing a glimpse of a United States that was only 85 years old at the time.