Answer:
20 May 1882 (The Triple Alliance formed),
August 8, 1918 (Triple Ententre formed),
Aug 4, 1914 (Germany invades Belgium),
31 October 1914 (Ottoman Empire joins the Central Powers),
September 3, 1939 (Great Britain declares war on Germany),
22 April 1915 (Germans first use poison gas),
July 1, 1916 (the Battle of the Somme),
1914 (Gavrilo Princip and the nationalist group, the Black Hand, plot to advance the cause of the unification of Slavic peoples),
September 6–12, 1914 (The British and the French armies stop the German advance on Paris at the Marne River),
July 28, 1914 (Austria-Hungary declares war on Serbia),
28 June 1914 (Archduke Franz Ferdinand, heir to the throne of Austria-Hungary, is assassinated),
February 21, 1916 (The Germans launch a major offensive—the Battle of Verdun),
August 1, 1914 (Germany declares war on Russia),
1906 and 1914 (Germany challenges British naval supremacy in Europe),
23 August 1914 (Japan, a rival of Germany in Asia, joins the Allies in war)
August 3, 1914 (Germany declares war on France)
Heres all the dates and what they correspond to (there out of order).