A little known fact lost to history is that chlorine gas was used during WWI as a peace offering. The Allies and Central Powers used to lob canisters of it from one side to the other. The hope was that anyone with a cold—and there were many cases in those dreary, wet trenches—would start to feel better. Unfortunately, the goodwill, much like the Christmas Truce, was short lived, and the men would soon be back to trying to kill each other.