Flame throwers, spy trees, bird bombs, and Hell Fighters were all a part of World War I, but you won't learn that in your history books! Uncover long-lost secrets of spies like Howard Burnham, "The One Legged Wonder," and nurse-turned-spy, Edith Cavell. Peek into secret files to learn the truth about the Red Baron and the mysterious Mata Hari. Then build your own Zeppelin balloon and mix up some invisible ink. It's all part of the true stories from the Top Secret Files of History. Take a look if you dare, but be careful! Some secrets are meant to stay hidden. ..