World War One is the watershed moment in modern history. The Western World before it was one of aristocrats, empires, colonies, and optimism for a future of unending progress. After four years of hellish trench warfare, shell fire, 10 million combat deaths, and another 10 million civilian deaths, the world that emerged in 1918 was irrevocably changed. Nation-states came out of the rubble, along with a push for universal rights. New technologies emerged, such as tanks and fighter planes. But...