World War I

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)[a] 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)[b] 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)[c] United States–Austria Peace Treaty Signed 24 August 1921 (3 years, 8 months, 2 weeks and 3 days)[d][e] United States–Germany Peace Treaty Signed 25 August 1921 (4 years, 4 months, 2 weeks and 5 days)[f] United States–Hungary Peace Treaty Signed 29 August 1921 (3 years, 8 months, 3 weeks and 1 day)[g] Treaty of Lausanne Signed 24 July 1923 (8 years, 8 months, 3 weeks and 4 days)[h] Location Europe Middle East Africa Pacific Atlantic Mediterranean and Adriatic Result Allied victory Central Powers victory on the Eastern Front is made worthless by defeat on the Western Front All empires in mainland Europe collapse (including Germany, Russia, Turkey and Austria-Hungary) Russian Revolution and Russian Civil War – the Russian Empire becomes the Soviet Union Widespread unrest and revolutions throughout Europe and Asia Creation of the League of Nations (more...) Territorial changes Formation of new countries in Europe and the Middle East Transfer of German colonies and territories, regions of the former Ottoman Empire, regions of the former Austro-Hungarian Empire and Soviet Union territories to other countries
Belligerents
Allied Powers:  France (1914-1918)  United Kingdom (1914-1918)  Russia (1914–1917)  Japan (1914-1918)  Italy (1915–1918)  United States (1917–1918) ...and others	Central Powers:  German Empire (1914-1918) Austria-Hungary (1914-1918)  Ottoman Empire (1914-1918)  Kingdom of Bulgaria (1915-1918) ...and co-belligerents
Commanders and leaders
Main Allied Leaders Raymond Poincaré H. H. Asquith David Lloyd George Nicholas II Vittorio Orlando Woodrow Wilson Yoshihito and others...	Main Central Leaders Wilhelm II Franz Joseph I † Mehmed V † Ferdinand I and others...
Strength
Total: 42,959,850[1] 12,000,000 8,841,541[2][3] 8,660,000[4] 5,615,140 4,743,826 1,234,000 800,000 707,343 380,000 250,000 50,000	Total: 25,248,321[1] 13,250,000 7,800,000 2,998,321 1,200,000
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... Military deaths by country[5][6] 1,811,000 1,397,800 1,114,914 651,000 250,000–335,000 275,000 116,708 58,637–87,500 26,000 3,000 415	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... Military deaths by country[5] 2,050,897 1,200,000 771,844 87,500

World War I (WWI or WW1), also called the First World War, began on July 28, 1914 and lasted until November 11, 1918. It was a global war and lasted exactly 4 years, 3 months and 2 weeks. Most of the fighting was in continental Europe.

Soldiers from many countries took part, and it changed the colonial empires of the European powers. Before World War II began in 1939, World War I was called the Great War, or the World War. Other names are the Imperialist War and the Four years War. There were 135 countries that took part in World War I, and nearly 10 million people died while fighting.^[7]

Before the war, European countries had formed alliances to protect themselves. However, that made them divide themselves into two groups. When Archduke Franz Ferdinand of Austria was assassinated on June 28, 1914, Austria-Hungary blamed Serbia and declared war on it. Russia then declared war on Austria-Hungary, which set off a chain of events in which members from both groups of countries declared war on each other.

The two sides were the Allied Powers (mainly Russia, France, the British Empire and later the United States) and the Central Powers (mainly German Empire, Austria-Hungary and the Ottoman Empire).

There was fighting in many different fronts (areas). The French and the British fought the Germans on the Western Front in France and Belgium. Germany had tried to defeat France quickly with the Schlieffen Plan but were stopped in the First Battle of the Marne. Most of the fighting on the western front was trench warfare. The Russians fought the Germans and Austro-Hungarians on the Eastern Front in Central and Eastern Europe. Fighting on the eastern front was not trench warfare as in the west, but mobile warfare. The other main areas of fighting were in the Middle East, in the Gallipoli region of the Ottoman Empire and between Italy and Austria-Hungary. Fighting also took place in Africa, China, at sea and in the air. World War I was the first major war in which tanks, airplanes and submarines (or U-boats) were important weapons.
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1. ↑ ^{1.0 1.1} Tucker & Roberts 2005, p. 273 harvnb error: no target: CITEREFTuckerRoberts2005 (help)
2. ↑ "British Army statistics of the Great War". Retrieved 13 December 2011.
3. ↑ Figures are for the British Empire
4. ↑ Figures are for Metropolitan France and its colonies
5. ↑ ^{5.0 5.1} "Page non disponible" (PDF). Archived from the original (PDF) on 2021-02-02. Retrieved 2019-06-19.
6. ↑ Nash (1976). Darkest Hours. Rowman & Littlefield. ISBN 978-1590775264.
7. ↑ "Military Casualties of World War One". Archived from the original on 2018-06-28. Retrieved 2008-03-10.