World War I 

World War I (WWI) was a global conflict that took place between 1914 and 1918. It began in Europe as an international war between the Central Powers of Germany, Austria-Hungary, Bulgaria, and the Ottoman Empire on one side and the Allied powers of France, Russia, Britain, and Italy on the other. WWI is known for its devastating human cost; it saw millions killed or wounded by poison gas attacks, artillery barrages, and trench warfare battles.

The causes of WWI are complex but include pre-war tensions over alliances among European countries, imperialism, particularly in Africa, militarism across all sides involved in the conflict, and a number of disputes about sovereignty within Europe's multi-ethnic empires. As well as its impact on Europe itself, WWI also had far-reaching consequences for much of Asia Minor, which was under Ottoman rule at the time.

WWI brought huge social changes to many parts of society, including advances in technology such as tanks being used for combat purposes rather than just transport vehicles during battle – something that changed how future wars were fought forever more. After four years of bitter fighting from 1914 to 1918, however, no clear victor emerged, with both sides eventually signing an armistice agreement that ended hostilities shortly after 11 a.m. on November 11th, 1918, hence why Remembrance Day is still commemorated every year around this date each November throughout most western world nations that participated directly or indirectly in this major historical event.