Margaretha Zelle (1876-1917), also known as Mata Hari, was a Dutch exotic dancer accused of being a double agent. Though she always denied being a spy, the French executed her in 1917.
French Second Lieutenant Alfred Joubaire wrote in his diary about WWI just before he died that “Humanity is mad! It must be mad to do what it is doing. What a massacre. What scenes of horror and carnage! I cannot find words to translate my impressions. Hell cannot be so terrible! Men are mad!”