You could say it was the assassination of the Archdule Franz Ferdinand.
Strictly, it was the mobilisation of Russia in support of Serbia, which put-out the German plan. This had depended on knocking-out France before turning on Russia. Now Russia needed attacking first, so Germany had to invade France via Belgium, whose neutrality had been guaranteed by Britain.
The Germans had been slowly building up their military after the fall of the Weimar Republic; their invasion of Poland in 1939 was probably the most immediate cause of the world war.
The German invasion of Poland in 1939.
The attack on Pearl Harbor
The assassination of Archduke Franz Ferdinand.
The main cause of world war 1 was all of the alliances nations made. It was also because Archduke Franz Ferdinand was assassinated by a terrorist.
The immediate cause of the first revolution in March 1917 was the disastrous impact of the First World War.
The Germans had been slowly building up their military after the fall of the Weimar Republic; their invasion of Poland in 1939 was probably the most immediate cause of the world war.
The German invasion of Poland in 1939.
the assassination of arch duke Ferdinand by the serbian political group "the black hand"
The attack on Pearl Harbor
The assassination of Archduke Franz Ferdinand.
That was the Archduke Franz Ferdinand.
The German invasion of Poland on 1 September 1939
The main cause of world war 1 was all of the alliances nations made. It was also because Archduke Franz Ferdinand was assassinated by a terrorist.
In Europe it was the attack of Poland by the German Nazis on 9-1-39. In the Pacific it was the attack on the US Naval Fleet at Pearl Harbor, Hawaii by the Japanese on 12-7-41 that was the immediate cause of World War 2 for the USA.
World War I had 4 long-term causes and one immediate cause. The assassination of the Austro-Hungarian archduke was the immediate cause, the reason war was justified enough to actually begin. The other four are the MAIN causes of the war, Miliatariam, Alliances, Imperialism and Nationalism.
It was Arch Duke Franz Ferdinand , his assassination lead to the first world war.