The First World War 1914-18 ended on 11th November 1918. It was the biggest war since that time and was called the Great War. More than 70 million military personnel participated in the war. More than 9 million army personnel were killed. It was only after the Second World War, that this war was named as First World war. It started on 28th July 1914 and continued till 11 November 1918. The main war was between the Allies (Britain, France, Russia etc.) and the Central Powers (Austria-Hungary, Germany, Italy etc.). Many other countries joined this side or that side.Almost all the European countries were involved in the war.
The October Revolution in Russia in 1917 and the fall of the Czar happened in between. The Central Powers were defeated. By the end of the war four empires had collapsed – Czarist Russia, Ottoman Empire, Austria-Hungary and Germany.
The League of Nations was formed to ensure world peace,but as history shows, it failed and the Second World War started by about two decades.