Western Front (World War I)

After the initial German advance of 1914 was halted at the Battle of the Marne (thwarting the Schlieffen Plan), both sides tried unsuccessfully to outflank the other in the Race to the Sea. Deadlock followed, with defensive trench systems running from Belgium to the Swiss border. Attempts to break through with massed infantry attacks (for example, the battles of Champagne and Artois in 1915, of the Somme and Verdun in 1916, and of Passchendaele and the Chemin des Dames in 1917) resulted in massive losses with little territorial gain. From 1917 the conflict gradually became one of movement once again as both sides learned to devolve command to smaller, more flexible troop units. In February and March 1917 the Germans retreated to the Hindenburg line before specialized assault troops made large gains in the Ludendorff offensives of 1918, but exhausted Germany's resources in the process. Allied counterattacks advanced to the German border by the end of the war in November 1918.