The event that extended the war into 1915 and beyond was that the French stopped the German advance in the west.
World War I was an international conflict that in 1914–18 involved most of the nations of Europe along with Russia, the United States, the Middle East, and other regions. In the war the Central Powers—mainly Germany, Austria-Hungary, and Turkey fought against the Allies—mainly France, Great Britain, Russia, Italy, Japan, and, from 1917, the United States. In the end, the Central Powers were defeated.
