- 
  
  Outbreak of World War I; German declaration of war on Russia.
- 
  
  
- 
  
  Germany announces "war zone" in British waters
- 
  
  Germany resumes U-boat attacks under search and destroy rules
- 
  
  Soviet Russia and Central Powers make peace with Treaty of Brest-Litovsk
- 
  
  Germany admitted to League of Nations
- 
  
  Germany quits the League of Nations.
- 
  
  Britain and Poland sign a Mutual Assistance Treaty.
- 
  
  Finland signs a peace treaty with Soviets.
- 
  
  France signs an armistice with the Nazis.
- 
  
  Germans begin a U-boat offensive along east coast of USA.