This song is about the "Lost Battalion:" a group of nine companies from the U.S. Army's 77th Infantry Division, led by Maj. Charles W. Whittlesey, who became isolated by German forces during the Meuse-Argonne Offensive in the First World War.
Song by the Swedish heavy metal group Sabaton about the Battle of Belgrade in 1915 between the Serbian defenders and the Austo-Hungarian and German attackers during World War I.