1st World War

World War I
Clockwise from the top: The aftermath of shelling during the Battle of the Somme, Mark V tanks cross the Hindenburg Line, HMS Irresistible sinks after hitting a mine in the Dardanelles, a British Vickers machine gun crew wears gas masks during the Battle of the Somme, Albatros D.III fighters of Jagdstaffel 11
Date 28 July 1914 – 11 November 1918 (1914-07-28 – 1918-11-11) (4 years, 3 months and 2 weeks) Peace treaties Treaty of Versailles Signed 28 June 1919 (4 years and 11 months) Treaty of Saint-Germain-en-Laye Signed 10 September 1919 (5 years, 1 month, 1 week and 6 days) Treaty of Neuilly-sur-Seine Signed 27 November 1919 (4 years, 1 month, 1 week and 6 days) Treaty of Trianon Signed 4 June 1920 (5 years, 10 months and 1 week) Treaty of Sèvres Signed 10 August 1920 (6 years, 1 week and 6 days) United States–Austria Peace Treaty Signed 24 August 1921 (3 years, 8 months, 2 weeks and 3 days) United States–Germany Peace Treaty Signed 25 August 1921 (4 years, 4 months, 2 weeks and 5 days) United States–Hungary Peace Treaty Signed 29 August 1921 (3 years, 8 months, 3 weeks and 1 day) Treaty of Lausanne Signed 24 July 1923 (8 years, 8 months, 3 weeks and 4 days) Location Europe, Africa, the Middle East, the Pacific Islands, China, Indian Ocean, and off the coast of South and North America Result Allied Powers victory Central Powers' victory on the Eastern Front nullified by defeat on the Western Front Fall of the German, Russian, Ottoman, and Austro-Hungarian empires Russian Civil War and foundation of the Soviet Union Formation of new countries in Europe and the Middle East Transfer of German colonies and regions of the former Ottoman Empire to other powers Establishment of the League of Nations. (more...)
Belligerents
Allied Powers  France  British Empire  Russia (until 1917)  Serbia  Belgium  Montenegro  Japan  Italy (1915–18)  United States (1917–18)  Romania (1916–18)  Portugal (1916–18) Hejaz (1916–18) China (1917–18)  Greece (1917–18) Siam (1917–18) ...and others	Central Powers  German Empire  Austria-Hungary  Ottoman Empire  Bulgaria (1915–18) ...and co-belligerents
Commanders and leaders
Allied leaders Raymond Poincaré Georges Clemenceau H. H. Asquith David Lloyd George Nicholas II Victor Emmanuel III Vittorio Orlando Woodrow Wilson Yoshihito Peter I Ferdinand I Eleftherios Venizelos ...and others	Central Powers leaders Wilhelm II Franz Joseph I † Karl I Mehmed V † Mehmed VI Three Pashas Ferdinand I ...and others
Strength
12,000,000 8,841,541 8,660,000 5,615,140 4,743,826 1,234,000 800,000 707,343 380,000 250,000 50,000 Total: 42,959,850	13,250,000 7,800,000 2,998,321 1,200,000 Total: 25,248,321
Casualties and losses
Military dead: 5,525,000 Military wounded: 12,831,500 Total: 18,356,500 KIA, WIA and MIA Civilian dead: 4,000,000 ...further details. 908,000 killed 1,135,000 killed 650,000 killed 1,700,000 killed 335,000 killed 87,500 killed 116,000 killed	Military dead: 4,386,000 Military wounded: 8,388,000 Total: 12,774,000 KIA, WIA and MIA Civilian dead: 3,700,000 ...further details. 1,800,000 killed 1,200,000 killed 325,000 killed

Allied Powers victory

...further details.

...further details.

World War I (often abbreviated as WWI or WW1), also known as the First World War or the Great War, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. Contemporaneously described as the "War to End All Wars", more than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history. Over nine million combatants and seven million civilians died as a result of the war (including the victims of a number of genocides), a casualty rate exacerbated by the belligerents' technological and industrial sophistication, and the tactical stalemate caused by gruelling trench warfare. It was one of the deadliest conflicts in history and precipitated major political change, including the Revolutions of 1917–1923 in many of the nations involved. Unresolved rivalries at the end of the conflict contributed to the start of the Second World War twenty-one years later.

The war drew in all the world's economic great powers, assembled in two opposing alliances: the Allies (based on the Triple Entente of the Russian Empire, the French Third Republic, and the United Kingdom of Great Britain and Ireland) versus the Central Powers of Germany and Austria-Hungary. Although Italy was a member of the Triple Alliance alongside Germany and Austria-Hungary, it did not join the Central Powers, as Austria-Hungary had taken the offensive against the terms of the alliance. These alliances were reorganised and expanded as more nations entered the war: Italy, Japan and the United States joined the Allies, while the Ottoman Empire and Bulgaria joined the Central Powers.

...
Wikipedia