The following photos were taken from 1914-1918 by my great-grandfather Lt. Walter Koessler during his time as a German officer in the first World War. They're part of a collection of over a thousand photos, stereographs and their negatives that my family has been saving for a century. This is an unusually large and complete collection, and I've taken on the task of preserving it and printing it so other people can experience this history too. These photos have never been published before.