- 42 BC Roman Republican civil wars: Second Battle of Philippi - Brutus's army is decisively defeated by Mark Antony and Octavian. Brutus commits suicide.
- 1942 During WW II, Britain launches major offensive at El Alamein, Egypt
- 1977 Paleontologist Elso Barghoorn announces that 34-billion-year-old one-celled fossils, the earliest life forms, had been discovered
- 1981 US national debt hits $1 trillion
- 2001 The Provisional Irish Republican Army of Northern Ireland commences disarmament after peace talks
Tornado (possible T8/F4) strikes the heart of London killing two and demolishing the wooden London Bridge
On October 23, 1091