World War I began in 1914 after the assassination of Archduke Franz Ferdinand of Austria-Hungary by Serbian nationalists. This triggered a series of events that led major European powers to take sides along the Allied and Central Powers alliance system. Germany launched the Schlieffen Plan to quickly defeat France but it failed after the British joined the war. Both sides then dug extensive trench systems that stretched for hundreds of miles, leading to brutal stalemate warfare for most of the war. Over 20 million soldiers and civilians lost their lives before an armistice ended the war in 1918.

1. World War I

10. The Schlieffen Plan’s Destructive Nature

15. The Trenches

36. Death Toll of War Allied Powers Central Powers 42 million served 23 million served 22 million casualties 15 million casualties