What year did World War I begin?

The story behind the answer

1914 is correct because World War I began after the assassination of Archduke Franz Ferdinand on June 28, 1914, which triggered a chain of alliance obligations. Austria-Hungary declared war on Serbia on July 28, and by early August major powers were drawn in—Germany invaded Belgium, prompting Britain’s entry on August 4. The other dates refer to different events: 1905 (Russo-Japanese War/First Moroccan Crisis), 1919 (Treaty of Versailles), 1925 (Locarno Treaties).

Context: WWI (1914–1918) was the first truly industrialized global war, marked by trench warfare and massive casualties, and it toppled empires (Austro-Hungarian, Ottoman, Russian). Memory tip: “’14 to ’18”—the war starts at 14 and ends at 18, like teenage years; or think “Guns of August 1914,” the famous phrase about its opening month.