Events of World War I
1. 1914- 1918
-------- Germany resumes unrestricted submarine warfare Battles of Verdun and the Somme War begins; Ottoman Empire joins the Central Powers United States enters the war Italy joins the Triple Entente; German submarine sinks the Lusitania ; Germany halts unrestricted submarine warfare Treaty of Versailles Serbian nationalist assassinates Archduke Francis Ferdinand World War I Battle of the Marne; German victories on the eastern front
2. June 28, 1914
-------- Germany resumes unrestricted submarine warfare Battles of Verdun and the Somme War begins; Ottoman Empire joins the Central Powers United States enters the war Italy joins the Triple Entente; German submarine sinks the Lusitania ; Germany halts unrestricted submarine warfare Treaty of Versailles Serbian nationalist assassinates Archduke Francis Ferdinand World War I Battle of the Marne; German victories on the eastern front
3. August 1914
-------- Germany resumes unrestricted submarine warfare Battles of Verdun and the Somme War begins; Ottoman Empire joins the Central Powers United States enters the war Italy joins the Triple Entente; German submarine sinks the Lusitania ; Germany halts unrestricted submarine warfare Treaty of Versailles Serbian nationalist assassinates Archduke Francis Ferdinand World War I Battle of the Marne; German victories on the eastern front
4. September 1914
-------- Germany resumes unrestricted submarine warfare Battles of Verdun and the Somme War begins; Ottoman Empire joins the Central Powers United States enters the war Italy joins the Triple Entente; German submarine sinks the Lusitania ; Germany halts unrestricted submarine warfare Treaty of Versailles Serbian nationalist assassinates Archduke Francis Ferdinand World War I Battle of the Marne; German victories on the eastern front
5. 1915
-------- Germany resumes unrestricted submarine warfare Battles of Verdun and the Somme War begins; Ottoman Empire joins the Central Powers United States enters the war Italy joins the Triple Entente; German submarine sinks the Lusitania ; Germany halts unrestricted submarine warfare Treaty of Versailles Serbian nationalist assassinates Archduke Francis Ferdinand World War I Battle of the Marne; German victories on the eastern front
6. 1916
-------- Germany resumes unrestricted submarine warfare Battles of Verdun and the Somme War begins; Ottoman Empire joins the Central Powers United States enters the war Italy joins the Triple Entente; German submarine sinks the Lusitania ; Germany halts unrestricted submarine warfare Treaty of Versailles Serbian nationalist assassinates Archduke Francis Ferdinand World War I Battle of the Marne; German victories on the eastern front
7. 1917
-------- Germany resumes unrestricted submarine warfare Battles of Verdun and the Somme War begins; Ottoman Empire joins the Central Powers United States enters the war Italy joins the Triple Entente; German submarine sinks the Lusitania ; Germany halts unrestricted submarine warfare Treaty of Versailles Serbian nationalist assassinates Archduke Francis Ferdinand World War I Battle of the Marne; German victories on the eastern front
8. April 1917
-------- Germany resumes unrestricted submarine warfare Battles of Verdun and the Somme War begins; Ottoman Empire joins the Central Powers United States enters the war Italy joins the Triple Entente; German submarine sinks the Lusitania ; Germany halts unrestricted submarine warfare Treaty of Versailles Serbian nationalist assassinates Archduke Francis Ferdinand World War I Battle of the Marne; German victories on the eastern front
9. 1919
-------- Germany resumes unrestricted submarine warfare Battles of Verdun and the Somme War begins; Ottoman Empire joins the Central Powers United States enters the war Italy joins the Triple Entente; German submarine sinks the Lusitania ; Germany halts unrestricted submarine warfare Treaty of Versailles Serbian nationalist assassinates Archduke Francis Ferdinand World War I Battle of the Marne; German victories on the eastern front