The July Crisis could not be defused. On July 28th, 1914, Austro-Hungarian forces began shelling the city of Belgrade, for which the Russian Empire mobilised its armed forces. In response, the German Empire upheld its alliance with the Austrians, causing the French to uphold their alliance with the Russians. With total war on the horizon, a German invasion of Belgium triggered Britain's entrance into the Entente forces, while Italy and the Ottoman Empire joined the Central Powers. This complex web of alliances activating caused the beginning of the Great War, the grand European war which statesmen had feared in the last 100 years.
In German articles the conflict is known as the Weltkrieg (lit. "World War"), while in the prior Commonwealth it is typically called the Great War.
This article acts as a hub for the following subarticles:
World War I - The Schlieffen Plan
World War I - The Battle of Tannenberg
World War I - The Balkan and Alpine Campaigns
World War I - British Campaigns in the Middle-East