World War 1 was a major war centred on Europe that began in the summer of 1914 and lasted until November 1918. It involved all of the world's great powers, assembled in two opposing alliances: the Allies and the Central Powers. More than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history. More than 9 million combatants were killed, largely because of great technological advances in firepower without corresponding advances in mobility. It was the second deadliest conflict in Western history.
The war was triggered off by many reasons. The most crucial one was the assassination of Archduke Franz Ferdinand of Austria, the heir to the throne of Austria-Hungary. This was a major reason why the countries started attacking one another.
When the war ended on 11 November 1918, the German, Russian, Austro-Hungarian and Ottoman Empires—had been militarily and politically defeated. Germany, the major powerhouse in the Central Power, was forced to sign the Treaty of Versailles, and was also forced to pay for war damage to other countries.
Because of the brutality and the family lost during the war, people in Europe cherished peace and family more after the World War 1. Many countries' government also began to govern their countries with more mercy. As Germany was still “sick” from the World War 1, they continued to disturb others and started World War 2