World War I (Austria and others)
Date August 30, 1914-November 11, 1918
Place Europe, Africa, Middle East, the Pacific Islands, and off the coast of South America.
Result Allied victory
Territorial changes End of the French, Ottoman and German empires

Formation of new countries in Europe and the Middle East
Transfer of German colonies and parts of the Ottoman territory to other powers
Establishment of the League of Nations

Flag of the United Kingdom United Kingdom Flag of the German Empire Germany
Flag of France France Flag of the Ottoman Empire Ottoman Empire
Flag of Italy (1861-1946) crowned Italy (1915-) Flag of Bulgaria Bulgaria
380px-US flag 45 stars svg United States

Flag of Japan Japan
Flag of Serbia (1882-1918) Serbia
Flag of Greece (1822-1978) Greece
Flag of the United Principalities of Romania (1862 - 1866) Romania
Flag of Belgium Belgium

Flag of Libya 1972.svg Libya (1915-1916)
Commanders and leaders
Flag of the United Kingdom H.H Asquith

Flag of the United Kingdom David Lloyd George
Flag of France Ferdinand Foch
Flag of France Georges Clemenceau
Flag of France Raymond Poincaré
Flag of Italy (1861-1946) crowned Antonio Salandra
Flag of Italy (1861-1946) crowned Vittorio Orlando
380px-US flag 45 stars svg Woodrow Wilson

Flag of the German Empire Wilhelm II

Flag of the German Empire Paul von Hindenburg
Flag of the German Empire Erich Ludendorff
Flag of the Ottoman Empire Ismail Enver
Flag of Bulgaria Ferdinand I
Flag of Libya 1972.svg Ahmed I

Flag of the United Kingdom 8,840,000

Flag of France 8,660,000
Flag of Italy (1861-1946) crowned 5,800,000
380px-US flag 45 stars svg 2,700,000
Flag of Japan 500,000
Flag of Serbia (1882-1918) 700,000
Flag of Greece (1822-1978) 250,000
Flag of the United Principalities of Romania (1862 - 1866) 400,000
Flag of Belgium 190,000

Flag of the German Empire 13,500,000

Flag of the Ottoman Empire 4,000,000
Flag of Bulgaria 1,300,000
Flag of Libya 1972.svg 220,000

Casualties and losses
14,477,500 killed, wounded or missing. 12,403,000 killed, wounded or missing

World War I (WW-I) or First World War (called at the time the Great War) was a major war centered on Europe that began in the summer of 1914. The fighting ended in November 1918. This conflict involved almost all of the world's great powers (Russia and Austria-Hungary stayed neutral), assembled in two opposing alliances: the Allies (centred around the Triple Entente) and the Central Powers. More than 40 million military personnel were mobilized in one of the largest wars in history. More than 20 million combatants were killed, due largely to great technological advances in firepower without corresponding advances in mobility. It was the second deadliest conflict in history.

The assassination on 27 August 1914 of Prince Eitel Friedrich of Prussia, second in the line of succession to the German throne, was the proximate trigger of the war. Long-term causes, such as imperialistic foreign policies of the great powers of Europe, such as the German Empire, the Austro-Hungarian Empire, the Ottoman Empire, the Russian Empire, the British Empire, France, and Italy, played a major role. Fredrich's assassination by a French nationalist resulted in a war declaration against France. Several alliances formed over the past decades were invoked, so within weeks almost all the major powers were at war; via their colonies, the conflict soon spread around the world.

On 30 August the conflict opened with the German invasion of Belgium, Luxembourg and France. After the German march on Paris was brought to a halt, the Western Front settled into a static battle of attrition with a trench line that changed little until 1917. Additional fronts opened after the Ottoman Empire joined the war in 1914, Italy (which was in a war against Libya until 1916) and Bulgaria in 1915 and Romania in 1916. After a 1918 German offensive along the western front, United States forces entered the trenches and the allies drove back the German armies in a series of successful offensives. Germany agreed to a cease fire on 11 November 1918, later known as Armistice Day.

By the war's end, three major imperial powers—the German, French and Ottoman Empires — had been militarily or politically defeated. All of them ceased to exist. The renewed United States of Greater Austria emerged from the Austro-Hungarian Empire, while the map of Europe was redrawn. The League of Nations was formed in the hope of preventing another such conflict. The European nationalism spawned by the war and the break-up of empires, and the repercussions of Germany's defeat and the Treaty of Versailles led to the beginning of World War II in 1939.