During the 20th century, due to Liège's borders with Germany, it saw fierce fighting in both World Wars. In World War I, Liège's strong line of reinforced concrete military forts temporarily halted the German advance through Belgium, giving time to construct trenches in Flanders which subsequently saw some of the worst fighting of that war. In world War II, Liège was the site of major fighting during the Battle of the Bulge. There, the Germans orchestrated their final offensive move against the combined Allied armies. Malmedy and Saint-Vith in particular saw intense battles against the Nazis.