World War One was a war between the major powers of Europe that can not be said to have had one specific cause.
Having a colony at that time was the thing to have.
Because it was such a sought after entity, it caused many tensions between the major imperialistic powers in Europe. Middle It is also thought that a World War might not have been possible had it not have been for the expansions of the armies.
Alliances and Ententes Were to Blame for the Outbreak of World War One (WWI) In August 1914, World War One broke out.
The main cause of the war has never been established and has been among the many debates among historians studying this period.
It can also be said that nationalism caused the Serbian rebel group, the Black Hand, to shoot and kill the Archduke Franz Ferdinand and his wife.
Nationalism was also a reason for long term tensions between France and Germany.
If Germany had not allied with Austria-Hungary war might have been averted.
Throughout the 19th century and the beginning of the 20th century countries were in constant conflict.
When Germany unified as one country they were determined to show their strength and try to prove themselves as a great power in Europe.
To prove themselves they attacked France, won and gained the land of Alsace-Lorraine.