October 21: Trafalgar Day in the United Kingdom, Overseas Chinese Day in the Republic of China.
- 1805: Napoleonic Wars: Lord Nelson (pictured) led the British fleet to victory in the Battle of Trafalgar, defeating Pierre-Charles Villeneuve and his combined French and Spanish navy.
- 1824: English stonemason, bricklayer and inventor Joseph Aspdin patented Portland cement.
- 1854: Florence Nightingale and a staff of 38 nurses were sent to the Crimean War.
- 1944: World War II: HMAS Australia was hit in the first kamikaze attack; 30 crewmen were killed, including the commanding officer.
- 1945: Argentine military officer and politician Juan Domingo Perón married popular actress Eva Duarte, better known as Evita.
Recent days: October 20 – October 19 – October 18
More anniversaries: