World War I, also known as the Great War, began after the assassination of Archduke Franz Ferdinand (heir to the Austro-Hungarian Empire) in Sarajevo (a city in Serbia; now the capital of Bosnia & Herzegovina) on 28 June 1914, and lasted until November 11, 1918.
During the conflict, Germany, Austro-Hungarian Empire, Ottoman Empire and Bulgaria (the Central Powers) fought against Great Britain, France, Russia, Italy, Romania, Japan, the United States, Greece, Serbia and the United States (the Allied Powers).
The winners were the Allied Powers, and it is estimated that this war has led to the death of more than 16 million people.