1915 by GregorSD, Luke Powell, Finfamous

In 1915, World War One introduced a weapon that changed warfare forever. Chemical gas attacks were first used on a massive scale, starting at Ypres in Belgium. Clouds of chlorine and later mustard gas drifted silently across battlefields. Soldiers had no warning. Many inhaled chemicals that burned their lungs from the inside, leaving no visible wounds. Some survived the battlefield itself, but suffered permanent damage to their breathing, eyesight, and health for the rest of their lives. Gas war

1915 Penny Value Guide: See How Much A 1915 Wheat Penny With NO Mintmark, A 1915-D Penny, A 1915-S Penny, And 1915 Wheat Penny Errors Are Worth

Letters from the First World War, part one - The National Archives

Armenian Genocide Began — This Happened: April 24