World war 1 began on the 4 August 1914, Britain declared war on Germany.It became known as the great war, as it affected people all over the world.
The war was between Germany and Great Britain ,Austria-Hungary and France, the allies and Russia.
Great Britain, Germany, Austria-Hungary and Russia all ruled many countries (colonies) across the world. They wanted to keep their empires strong and saw other countries taking over new territories as a threat.
When Germany and Austria-Hungary took control of small countries like Bosnia and Morocco, the rest of the world thought they were being aggressive.
Many countries had made alliances with one other. They agreed to protect each other. If one was attacked, the others would defend them.
On 28 June 1914, Archduke Franz Ferdinand, the heir to the throne of Austria-Hungary, was shot and killed by a Serbian man who thought Serbia should control Bosnia instead of Austria.
Because its leader had been shot, Austria-Hungary declared war on Serbia. As a result:
Russia got involved because Russia had an alliance with Serbia.
Germany then declared war on Russia because Germany had an alliance with Austria-Hungary.
Britain declared war on Germany because of its invasion of neutral Belgium. Britain had agreements to protect both Belgium and France.
Many battles were fought using trench warfare.
Long ditches were dug in the ground. Soldiers lived in these trenches and sometimes climbed out to attack.
