The war to end all wars

World War I was a war without parallel - all previous wars were eclipsed by its scale of destruction.

It was a struggle between Europe's great powers, which were grouped into two hostile alliances.

The number of men mobilised by both sides: the central powers (Germany, Austria-Hungary, Bulgaria and Turkey), and the allied powers (Britain and Empire, France, Belgium, Russia, Italy, USA), totalled over 65 million.

When the fighting was finally over, no-one could tell exactly how many had been killed but historians estimate that up to 10 million men lost their lives on the battlefield - and another 20 million were wounded.

As well as all the great powers of Europe being involved, the war also extended into Asia and Africa.

Troops throughout the Commonwealth rallied to support Britain.Over three million came from Canada, Australia, New Zealand, South Africa and India.

Sea battles took place in the South Atlantic and the Pacific.

The USA also intervened in European affairs for the first time, with more than 100,000 American troops killed helping to guarantee an allied victory.

World War I is also regarded as the first "total war" in which the combatants mobilised all their resources, military, industrial and human, on a scale never before thought possible.

The war begins

Posters encouraged women to persuade their menfolk to go to war

The catalyst for the war was the death of Austria's Archduke Franz Ferdinand, who was assassinated while he was visiting Sarajevo, the capital of Bosnia, which was then part of the Austro-Hungarian empire.

He was assassinated in protest because many Bosnians wanted to be free from the empire to unite with neighbouring Serbia. In retaliation and urged on by Germany, Austria invaded Serbia.

Serbia called for help from Russia, which was suspicious of Austria's ambitions.

Each country in turn was drawn into the conflict.

Germany, keen to expand its empire, soon declared war on Russia and France and invaded Belgium and Luxembourg.

Most thought the war would be over by Christmas

Both Russia and France mobilised to protect their national territory.

Britain declared war on Germany for its violation of the independence and neutrality of Belgium.

None of the states that went to war realised how long it would last or how terrible the cost might be. Most thought it would be over in a few short months and that peace would return in 1915.

Once the war had begun, the initial reasons for being involved seemed to become less important. The great powers battled it out to see who would be left standing at the end.

Trench warfare

For the first time war involved the use of new technology such as aeroplanes, tanks and submarines. But it is trench warfare that remains the lasting image of World War I.

The increased power of the more modern weapons gave much greater advantages to defence, making it more difficult to win quick victories.

This led to often huge losses by the attackers - on the first day of the Battle of the Somme 60,000 British soldiers were killed or wounded.

Trench warfare created an endless demand for men, munitions and supplies with often no apparent gains or victories.

The armistice and after

10 million were killed in World War I

By the beginning of 1918 the tide of battle turned and the German armies began to retreat. Demoralised German workers, suffering from food and fuel shortages, threatened revolution at home.

German leaders feared a communist take-over and eventually asked the allies for peace. The armistice went into effect at 11am on 11 November, 1918.

The war resulted in a radical reshaping of the political map of Europe. It spelled the end of the Ottoman and Habsburg empires and was the catalyst for the Russian revolution.

It left much of Europe in severe economic hardship. As well as political changes the war led to social changes in Europe too - with wider opportunities and greater equality for women.

But 80 years later it is perhaps best remembered for the staggering loss of human life. In the decade following the Great War many had the firm conviction that it should be "the war to end all wars".