On the 19th October 1914, Allied and German forces engaged in the first of a number of battles to seize control of the strategically advantageous Belgian town of Ypres. In this first encounter, the brutal fighting continued until the 22nd November 1914. With heavy losses on both sides this early conflict concluded with an Allied victory.
Having enlisted as part of the Bavarian Army, Adolf Hitler saw action during the First Battle of Ypres; he can be seen in the below photograph on the far right with comrades of the 16th Bavarian Reserve Infantry Regiment.
The original image can be found here.
Attribution: Bundesarchiv, Bild 146-1974-082-44 / CC-BY-SA