The European conflict leading to significant territorial changes that was triggered by the assassination of Archduke Franz Ferdinand was World War I. This conflict, which began in 1914, involved many nations and was marked by trench warfare and widespread destruction. The war resulted in the collapse of empires, including the Austro-Hungarian and Ottoman empires. The Treaty of Versailles in 1919 imposed heavy reparations on Germany and redrew national boundaries, shaping 20th-century geopolitics and setting the stage for future conflicts.