How many years did World War I go on? and what year did it start?

The First World War lasted 4 years. It began on July 28, 1914 and ended on November 11, 1918. The reason for the war was the assassination of the heir to the Austrian throne Franz Ferdinand. The war was caused by territorial disputes between the world’s major powers. In order to strengthen their forces, these powers were united in two opposing alliances: the Triple Alliance and the Entente. The war ended with the Paris Conference, at which peace treaties were signed between the countries participating in the war, demands were made on Germany to pay reparations and reduce the number of troops.