World War I reshaped the global landscape from 1914 to 1918. Triggered by the assassination of Archduke Franz Ferdinand, the conflict quickly escalated into a global war, drawing in major powers through complex alliances and mobilizing entire societies for total war. The war introduced new technologies and tactics, from trench warfare to tanks and poison gas. Key battles like Verdun and the Somme resulted in massive casualties, while political upheavals like the Russian Revolution altered the course of the conflict. The war's aftermath redrew borders, toppled empires, and set the stage for future global tensions.