Here's some background information about World War I, also known as the First World War and the Great War, which lasted from 1914 to 1918.
Causes of World War I:
The assassination of Archduke Franz Ferdinand of Austria-Hungary by Gavrilo Princip, a Bosnian Serb, led to Austria-Hungary declaring war on Serbia.
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The Central Powers consisted of Austria-Hungary, Bulgaria, Germany and the Ottoman Empire (now Turkey).
The Allied Powers consisted of Belgium, France, Great Britain, Greece, Italy, Montenegro, Portugal, Romania, Russia, Serbia and the United States.
The United States declared neutrality until German submarine warfare threatened American commercial shipping.
US Troop Statistics:
(Source: Defense Casualty Analysis System)
Battle deaths: 53,402
Non-battle deaths: 63,114
Total deaths: 116,516
Total US soldiers wounded: 204,002
Total number of US troops that served in the conflict: 4,734,991
Other Military Casualties by Country:
(Source: Encyclopedia Britannica)
Austria-Hungary: 1,200,000 dead; 3,620,000 wounded
Belgium: 13,716 dead; 44,686 wounded
Bulgaria: 87,500 dead; 152,390 wounded
France: 1,357,800 dead; 4,266,000 wounded
Germany: 1,773,700 dead; 4,216,058 wounded
Great Britain: 908,371 dead; 2,090,212 wounded
Greece: 5,000 dead; 21,000 wounded
Italy: 650,000 dead; 947,000 wounded
Japan: 300 dead; 907 wounded
Montenegro: 3,000 dead; 10,000 wounded
Ottoman Empire (Turkey): 325,000 dead; 400,000 wounded
Portugal: 7,222 dead; 13,751 wounded
Romania: 335,706 dead; 120,000 wounded
Russia: 1,700,000 dead; 4,950,000 wounded
Serbia: 45,000 dead; 133,148 wounded
Grand total (including US): 8,528,831 dead; 21,189,154 wounded
June 28, 1914 - Gavrilo Princip, who has ties to the Serbian terrorist-type group the Black Hand, assassinates Archduke Franz Ferdinand of Austria-Hungary.
July 28, 1914 - Austria-Hungary declares war on Serbia.
August 1, 1914 - Germany declares war on Russia.
August 2, 1914 - Ottoman Empire and Germany sign a secret treaty of alliance.
August 4, 1914 - Germany invades Belgium. President Woodrow Wilson declares that the United States is neutral. Britain declares war on Germany.
August 10, 1914 - Austria-Hungary invades Russia, opening the fighting on the Eastern Front.
August 26-30, 1914 - Battle of Tannenberg, Prussia.
September 12, 1914 - First battle of the Aisne in France begins, marking the beginning of trench warfare.
November 3, 1914 - Russia declares war on the Ottoman Empire.
November 5, 1914 - Great Britain and France declare war on the Ottoman Empire.
April 22-May 25, 1915 - Second Battle of Ypres, marking the first wide-scale use of poison gas by Germany.
May 7, 1915 - A German U-20 submarine sinks the British passenger ship, the Lusitania; 1,198 are killed, including 128 Americans.
June 1915-November 1917 - Battles of the Isonzo, Italy.
1915 - Battle of Krithia, Gallipoli peninsula, Ottoman Empire.
February 21-July 1916 - Battle of Verdun, France, the war's longest battle, with almost a million casualties.
May 31-June 1, 1916 - Battle of Jutland, North Sea near Denmark - a sea battle between British and German navies.
July 1, 1916-November 1916 - First Battle of the Somme River, France. The British introduce the tank.
June 26, 1917 - American troops begin landing in France.
November 20, 1917 - Battle of Cambrai, France.
December 3, 1917 - Russia signs an armistice with Germany.
March 3, 1918 - Russia signs the Treaty of Brest-Litovsk, ending hostilities with the Central Powers and withdrawing Russia from this war.
March 21-April 5, 1918 - Second Battle of the Somme River.
September 29, 1918 - Bulgaria signs an armistice.
October 30, 1918 - Ottoman Empire signs an armistice.
November 3, 1918 - Austria-Hungary signs an armistice.
November 11, 1918 - Germany accepts the armistice terms demanded by the Allies, ending the war.
June 28, 1919 - The Treaty of Versailles is signed at the Palace of Versailles, France.