Wikipedia:Selected anniversaries/October 31
- 1517 - Martin Luther nailed his 95 Theses onto the door of a church in Wittenberg, Germany, marking the beginning of the Protestant Reformation.
- 1863 - The Maori Wars resumed as British forces in New Zealand led by General Duncan Cameron began their Invasion of the Waikato along the Waikato River.
- 1922 - Benito Mussolini became the youngest Premier in the history of Italy at age 39.
- 1941 - Gutzon Borglum and 400 workers completed the colossal busts of U.S. Presidents George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln at Mount Rushmore.
- 1984 - Prime Minister Indira Gandhi of India was assassinated by two of her own bodyguards. Riots soon broke out in New Delhi.
Recent days: October 30 - October 29 - October 28