There was no single event that started World War 1. There were many events, which over time, led to the massive breakout of World War 1.
Many claim that the assassination of Archduke Franz Ferdinand of Austria, done by a gang named "The Black Hand" while Ferdinand visited Serbia, started all of the chaos. However, had Germany not given Austria the blank check (which basically informed Austria of Germany's friendship in case of any wars), Russia would not have come to the aid of Serbia and entered the war. If Germany had not entered neutral Belgium (which violated an unwritten law of Europe), Great Britain and France would have not been involved.
Thus, there was not one single event, but multiple events that ultimately led to the total war known as World War 1.
The assassination of Archduke Franz Ferdinand of Austria
Archduke Ferdinand was assasinated.
Start of the war, victory in Europe and victory over Japan.
The War started when Adolf Hitler's Nazis Germany invaded Poland.
Hitler invaded Poland
In simplest terms, the main cause of World War two was World War one, consult your local history teacher for more information.
On September 1st 1939 the German army invaded neighboring Poland and caused what is known as today World War II.
The violent event in 1914 helped start World War 1 was the assassination of Franz Ferdinand.
Most historians agree that the German invasion of Poland on September 1, 1939, was the event that marked the start of World War 2.
The Germans invaded Poland early on the morning of September 1st, 1939. This was the start of World War II.
France
the start of the Vietnam War
Start of the war, victory in Europe and victory over Japan.
What event marked the start of the French and Indian war
The War started when Adolf Hitler's Nazis Germany invaded Poland.
It outraged the Austro-Hungarians and caused world war I.
Germany annexed Austria.
Hitler invaded Poland
which event sparked world war 1?