The area around Ypres was site of three major battles in World War I. In the First Battle of Ypres (October 31 to November 22, 1914) the British captured the town from the Germans. In the Second Battle of Ypres (April 22 to May 25, 1915) the Germans used poison gas for the first time on the Western Front (they had used it for the first time at at the Battle of Bolimow on January 1, 1915) and captured high ground east of the town. In the Third Battle of Ypres (July 21 to November 6, 1916; also known as the Battle of Passchendaele) the British recaptured the ridge at a terrible cost of lives.
British and United States soldiers in that war often referred to Ypres by the deliberate (presumably humorous) mispronunciation "Wipers".
The Menin Gate Memorial in Ypres is dedicated to the fallen soldiers of the war.