The spark of World War I was the assassination of Archduke Franz Ferdinand (he was about to be at the throne of Austria-Hungary). Archduke Franz Ferdinand was chosen as a target because Serbians thought that after he was at the throne, he would continue the harassment of Serbians living. The Serbian terrorists called "The Black Hand", were in charge of killing Archduke Franz Ferdinand, and they did.
Britain was the largest empire in the world, and it had the largest navy. The navy was so big and strong because the British needed to protect their empire. Kaiser William of Germany hated Britain for having a stronger navy than his. He took the German navy and made it bigger and also built many warships. When Britain heard this they started building more ships and made their navy bigger too. This pretty much went on for a while and then it made Germany and Brittan hate each other.
The systems of alliance were another major cause of War World I. There was a conflict between France and Germany about controlling the colonies, which lead to an even bigger conflict, the World War I. Europe at that time was divided into two alliances: Triple Entente contained Britain, France, and Russia and the Triple Alliance, that contained Austria, Germany, and Italy .
One of the other major causes during the War was new weapons. In other words military commanders were not quite ready to the war with it's modern weapons and new technologies such as machine guns, also the men built trenches that ran 500 miles. The First World War was the first war to use poison gas as a military weapon. Germans also had the first submarines and used them to defend Britain by sinking British ships. The sinking of Lusitania is the famous example of sub-warfare during World War I. The Lucitania had people on board, where 100 passengers were American citizens. After sinking Lusitania a letter was sent to the German Government by President Wilson to warn the German government against killing Americans citizens.
