World War I was a massive global conflict fought from 1914 to 1918, involving many of the world's major powers divided into two opposing alliances: the Allies (including Britain, France, and Russia, later joined by the United States) and the Central Powers (led by Germany, Austria-Hungary, and the Ottoman Empire). The war began in Europe after the assassination of an Austrian archduke triggered a chain reaction of military alliances, pulling nation after nation into the fighting.

This war introduced horrifying new military technologies: machine guns, poison gas, tanks, airplanes, and submarines. Soldiers fought from muddy trenches that stretched for hundreds of miles across France and Belgium, where battles could rage for months with staggering casualties yet gain only a few yards of ground. The Battle of the Somme alone resulted in over one million casualties.

World War I killed approximately 20 million people and wounded millions more. It destroyed empires that had existed for centuries, redrew the map of Europe and the Middle East, and created conditions that would eventually lead to World War II. People at the time called it “The Great War” or “the war to end all wars” because they couldn't imagine anything worse. Tragically, they were wrong.

The war ended on November 11, 1918, when Germany signed an armistice. Today we remember that date as Veterans Day in the United States and Remembrance Day in other countries.