Ypres, a medieval town in Belgium, was taken by the German Army at the beginning of the war. However, by early October, 1914, the British Expeditionary Force (BEF) was able to recapture the town. The 1st Battle of Ypres took place between 15th October and 22nd November, 1914. It is estimated that about 135,000 Germans were killed or badly wounded during this offensive.
In April, 1915, the German launched another major offensive at Ypres. After a brief preliminary bombardment, the Germans used chlorine gas against the French and Algerian troops defending the area north of the town. The troops fled in terror and left a 7km gap in the Allied line. Wearing primitive gas-masks, the Germans advanced cautiously into the gap. The arrival of the British Second Army blocked the German advance but the Allied forces had been disadvantaged by the loss of the high ground north of Ypres.
Heavy fighting and frequent gas attacks continued around Ypres until 25th May. The Allied line held, but the German Fourth Army was able to use its new higher positions to bombard the town with heavy artillery. This inflicted heavy losses and Ypres was virtually demolished by the German shells during this period.