As the war began, many nations had spent huge amounts of money and effort on a massive military buildup. This inevitably increased tension and rivalry among the major powers.

The spark that lit the fuse was the assassination of Austria-Hungary’s Archduke Franz Ferdinand by a Bosnian Serb nationalist on 28 June 1914. This sparked a series of political and diplomatic moves that turned a local conflict in south-east Europe into a world war with far-reaching consequences.

By 1916, the fighting on all fronts had become a bloodbath as modern weapons resulted in enormous casualties. To prevent further carnage, the armies began to dig trenches that would last for years and became known as the Western Front or Passchendaele.

Smaller European powers and their colonies picked sides. Britain wanted to protect its vast global empire and its sea trade. It also feared German domination of Europe and its challenge to British industrial and imperial supremacy. The United States had a reputation for neutrality but this was to change after the sinking of the passenger ship Lusitania by Germany in May 1915. This prompted public pressure to force the U.S. to join the war against Germany.

In 1918, the Russians collapsed as a result of internal political revolutions. The Allied forces then unleashed a massive and methodical offensive on the Western Front. This became known as the Hundred Days Offensive and resulted in a rapid Allied victory. With the Russian army defeated, Germany’s prospects deteriorated. By the end of the war, the Allied powers had won and over 16 million people-soldiers and civilians-had died.