- 
  
  On this date, the Archduke of Austria-Hungary visited Sarajevo, Bosnia. He, along with his wife, were killed by Gavrilo Princip, a 19 year old Serbian nationalist and member of the Black Hand.
 - 
  
  
 - 
  
  Austria-Hungary declares war on Serbia, exactly one month after a Serbian nationalist killed Archduke Franz Ferdinand.
 - 
  
  Germany declares war on Russia, who was already in the war against Austria-Hungary.
 - 
  
  The Ottoman Empire joins the Triple Alliance.
 - 
  
  Germany declares war on France.
 - 
  
  Germany invades Belgium, entering war with all Allied pawers. Belgium was a neutral country previously.
 - 
  
  The U.K. declares war on Germany because the U.K. were allies with Belgium, who were invaded by Germany.
 - 
  
  This battle was the first battle at Marne, France. Germany is defeated by France and is forced to retreat.
 - 
  
  The Race to Sea has begun between the Triple Alliance and the Allied Powers. Trenches are built on both sides and the western front is created.
 - 
  
  Italy sides with Russia, France and Great Britain.