The First World War (July 28, 1914-November 11, 1918) was one of the most widespread wars in the history of mankind.
The formal reason for the war was the events in Sarajevo, where on June 28, 1914, Bosnian Serb Gavrilo Princip killed the heir to the Austro-Hungarian throne Archduke Ferdinand and his morganatic wife Sofia Hotek.
The countries participating in the First World War were divided into two opposing camps: