In 1914, many countries of Europe became involved in a war called world war. It was the first time that people from different countries would fight against each other in a global war.

Nationalism was a new issue that created tensions between different countries. It was also linked to militarism and polarised the combatants in European politics.

Britain and Germany were rivals for control of the world’s seas and markets. They grew increasingly concerned about each other’s influence and power in the world.

The nations of Europe had been making alliances in order to protect each other when they were threatened by others. The Triple Entente was formed between France, Britain and Russia in 1907.

In January 1917, the President of the United States, Woodrow Wilson, decided to cut off diplomatic relations with Germany because of their attacks on American ships. However, he didn’t ask for a declaration of war because he doubted that the public would support him unless he provided ample proof that German submarines were attacking U.S. ships without warning.

After Germany invaded Belgium, Britain joined the war against Germany. The US then entered the war to help Britain.

The war was a devastating conflict. It killed over 15 million soldiers and injured 20 million more. The majority of the war was fought in trench warfare. Tanks and other weapons were introduced to replace the hand-to-hand fighting that had been used in previous wars. Barbed wire, explosive mines and poison gas were used to hinder infantry advances across “No Man’s Land” between the trenches of the opposing sides.