It was in the city of Sarajevo, in June 28, 1914, that the chain of events that started World War One was set off.
Within a month and a half, Europe’s five major powers were at war.
On June 28 Archduke Franz Ferdinand of Austria attended a military review - but during the visit he and his wife were killed by Gavrilo Princip, a nationalist that wanted the Austro-Hungarian Empire out of Bosnia.
While his murder was the immediate catalyst for the declarations of war that followed, a patchwork of mutual defence alliances made throughout Europe meant that if one country was attacked, another was likely to defend them.
Prior to World War One, Russia was in alliance with Serbia, Germany was in alliance with Austria-Hungary; France was in alliance with Russia; while Britain was in alliance with France, Russia and Belgium.
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Austria-Hungary blamed the Serbian government for the attack on the archduke and presented an unacceptable ultimatum to Serbia.
Serbia accepted most of the country’s demands but protested against two of them - prompting Austria-Hungary to sever diplomatic relations and declare war on its neighbour.
Belgrade came under Austro-Hungarian artillery fire, and Russia mobilised. Germany, on July 31, sent an ultimatum to Russia to stop - but this was ignored and on August 1 Germany declared war on Russia.
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France mobilised its forces - leading Germany to carry out what was known as the Schlieffen Plan, which would involve an attack on France via Belgium.
On August 3 Germany declared war on France, and the next day the country’s forces invaded Belgium.
Britain was said to have been much less committed to its alliance with France and Russia than the other powers - but the UK had in 1839 signed a treaty with Belgium which said it would attack anyone who attacked it.
This meant that Britain was also likely to be dragged into the conflict, and on August 4 1914 Great Britain declared war on Germany.