The peace treaty ending the war between Germany and the Allies is signed in the Hall of Mirrors, imposing war guilt, territorial losses and heavy reparations on Germany.
Troops under General Reginald Dyer fire on an unarmed crowd in Amritsar, killing hundreds and fuelling anti-colonial sentiment.
An H1N1 influenza pandemic spreads worldwide, killing tens of millions of people, one of the deadliest pandemics in history.
Former Tsar Nicholas II, his wife, their children and their retainers are shot by the Bolsheviks in Yekaterinburg.
The Nineteenth Amendment is ratified, prohibiting denial of the right to vote on the basis of sex in the United States.
The Bolshevik Red Army fights the White movement and other forces after the October Revolution; the Bolsheviks emerge victorious.
Protests and mutinies in Petrograd force Tsar Nicholas II to abdicate, ending more than three centuries of Romanov rule.