In what year did the First World War begin and end?

World War I began in 1914 and ended in 1918. Military operations took place mainly on the territory of European countries and were divided into several fronts. The countries involved in the war were divided into two warring military alliances, which were called the Entente and the Quadruple Alliance. The Entente countries, which remained in the war until the very end, were defeated. Russia took part in the war on the part of the Entente, but withdrew from it in 1917 and for this reason is not considered a victorious country.