From First Shot to the Silence of Peace: Timeline of World War I

As the world marks 100 years since the fighting stopped, here's a look at some of the war's key moments

The Archduke of Austria Franz Ferdinand, center right, and his wife Sophie, center left, walk to their a car in Sarajevo, on June 28, 1914. This photo was taken minutes before the assassination of the Archduke and his wife.
AP Photo, File

Unleashed by an archduke’s assassination, World War I gradually entangled more and more countries, killing millions of soldiers and civilians and touching multiple continents.

As the world marks 100 years since the fighting stopped, here is a look at some key moments in WWI:

1914

June 28: Serb teenager Gavrilo Princip kills Austrian Archduke Franz Ferdinand

July 28: Austria-Hungary declares war on Serbia

Picture of a post card shows French artillery soldiers with a 75 mm cannon in 1914.
AFP

August 1: Germany declares war on Russia

August 3: Germany declares war on France

August 4: Germany invades Belgium; Britain declares war on Germany

August 23: Japan declares war on Germany

September: Battle of the Marne stops the German advance in France

October 29: Ottoman Empire enters the war

November: Beginning of trench warfare

December 25: Unofficial Christmas Truce

1915

February: German U-boat campaign marks first large use of submarines in warfare

April: Allied troops land in Gallipoli, Turkey, a defining moment for Australian, New Zealand

April 22: First use of a chemical weapon, chlorine gas, near Ypres, Belgium

May 7: British ship Lusitania sunk by German U-boat

May 23: Italy enters war, against Austria-Hungary

October: Bulgaria joins war, on side of Central Powers

1916

February 21: Battle of Verdun begins

March 9: Germany declares war on Portugal

July 1: Battle of the Somme begins, with first mass use of tanks

Photo taken in 1916 shows French soldiers moving into attack from their trench during the Verdun battle, eastern France.
AFP

August 27: Romania enters war, is invaded by Germany

September 4: British take Dar es Salaam in German East Africa

October: Soldier Adolf Hitler wounded

December 23: Allied forces defeat Turkish in Sinai Peninsula

1917

March: Baghdad falls to Anglo-Indian forces

April 6: United States declares war on Germany

April: Battle for Vimy Ridge , defining moment for Canada

July: Last Russian offensive ends in failure, as revolution nears; inconclusive Battle of Passchendaele in Belgium

October 15: Spy Mata Hari executed by French firing squad

October 26: Brazil declares war, joining Allied Powers

December: Battle of Jerusalem

1918

March 3: Treaty of Brest-Litovsk ends Russia’s involvement in the war on the Eastern Front.

April 21: Legendary German fighter pilot known as the Red Baron shot down and killed near Amiens, France

June: Battle of Belleau Wood , defining moment for U.S. military

July 21: German submarine fires on Cape Cod, only attack on mainland U.S.

Sept. 26: Battle of the Meuse-Argonne begins

October 30: Ottoman Empire signs armistice with Allies

October 31: Dissolution of Austro-Hungarian Empire

November 9: Germany’s Kaiser Wilhelm II abdicates

November 11: Germany signs armistice ending the war