The Yser River was the site of a major battle during World War I. The Battle of Yser was fought between German and Belgian forces in October 1914. It was a decisive victory for the Belgians, who were able to hold off the German advance and prevent them from taking control of the river. The battle was significant in that it marked the first time that the Belgian army had successfully defended its territory against a foreign invader. The Yser River remains an important symbol of Belgian national pride and is commemorated annually on the anniversary of the battle.