The second battle of Ypres was the first time people (German)used chlorine gas as a weapon. Germans had on gas masks(which they invented)when they used chlorine gas as a grenade. This weapon was illegal in war and if you were caught with it you would be killed. 6,000 people died of suffer-cation due to gas or from the ensuing attack. The interesting fact is that although the Germans were unfair the Canadians held their ground and never lost to Them.
Coin Gallery London Store - Canada: 2015 $20 First World War: Battlefront Series - The Second Battle of Ypres Silver Coin, $109.95 (http://www.coingallerylondon.com/canada-2015-20-first-world-war-battlefront-series-the-second-battle-of-ypres-silver-coin/)