Intro to the War
The event that led to the start of World War I is the assassination of Austria's Archduke Franz Ferdinand and his wife Sophie. This gave Austria Hungary a great excuse to attack Serbia, but they made sure they had the Germany's help before. They weren't the only ones getting back up though, Serbia had the backing of Russia who had the backing of France and Britain as well. By the time the war started the major players were The Allies (France, United Kingdom, and Russia) and the Central Powers (Germany and Austria-Hungary). Eventually, the war reached a stalemate, causing trench warfare to begin.