During World War I and World War II, Switzerland maintained armed neutrality, and was not invaded by its neighbors, in part because of its topography, much of which is mountainous. Germany was a threat and Switzerland built a powerful defense. It served as a "protecting power" for the belligerents of both sides, with a special role in helping prisoners of war. The belligerent states made it the scene for diplomacy, espionage, and commerce, as well as being a safe haven for 300,000 refugees.

World War I or the First World War was a global conflict between two coalitions: the Allies and the Central Powers. Fighting took place throughout Europe, the Middle East, Africa, the Pacific, and parts of Asia. One of the deadliest wars in history, it resulted in an estimated 9 million soldiers dead and 23 million wounded, plus up to 8 million civilian deaths from numerous causes including genocide. The movement of large numbers of troops and civilians during the war was a major factor in spreading the 1918 Spanish flu pandemic.