In 1914, the German Army opened the Western Front by first invading Luxembourg and Belgium, then gaining military control of important industrial regions in France. The tide of the advance was dramatically turned with the Battle of the Marne. Following the race to the sea, both sides dug in along a meandering line of fortified trenches, stretching from the North Sea to the Swiss frontier with France. This line remained essentially unchanged for most of the war.
Between 1915 and 1917 there were several major offensives along this front. The attacks employed massive artillery bombardments and massed infantry advances. However, a combination of entrenchments, machine gun nests, barbed wire, and artillery repeatedly inflicted severe casualties on the attackers and counterattacking defenders. As a result, no significant advances were made. Among the most costly of these offensives were the Battle of Verdun with a combined 700,000 dead the Battle of the Somme with more than a million casualties, and the Battle of Passchendaele with roughly 600,000 casualties.
