World War I (or the First World War) was a global war which began on July 28, 1914 and lasted until November 11, 1918. The war lasted exactly four years, three months and 14 days.Most of the fighting was in Europe, but soldiers from many other countries took part, and it changed the colonial empires of the European powers. Before World War II began in 1939, World War I was called the Great War, the World War or the 'war to end all wars'. 135 countries took part in World War I, and more than 9 million people died while fighting.[5]World War I was fought by most of the countries of Europe. The actual fighting was on many different fronts. The Western Front was where most of the fighting between Germany and the Allies happened. Most of the fighting here was trench warfare.The Eastern Front was fought in Central and Eastern Europe and was one of the main places where World War I took place. The fighting on the Eastern Front was not trench warfare but mobile warfare. The other fronts that had a lot of fighting include the Middle Eastern Front and the Italian Front. Fighting also took place in Africa, China, and at sea as well as in the air.The war was ended by the signing of many different treaties, the most important being the Treaty of Versailles.World War I was the first major war where tanks, aeroplanes, and submarines or (U-boats) were used as weapons.