Wikipedia:Selected anniversaries/October 21
This is a list of selected October 21 anniversaries that appears on the "On this day" section of the Main Page. To suggest a new item, in most cases you can be bold and edit this page. Please read the selected anniversaries guidelines before making your edit. However, if your addition might be controversial, or on a day that is or soon will be on the Main Page, please post your suggestion on the talk page instead.
Please note that the events listed on the Main Page are chosen based more on relative article quality and to maintain a mix of topics, not based solely on how important or significant their subjects are. Only 5–6 events are posted at a time and thus not everything that is "most important and significant" can be listed. In addition, an event is not generally posted this year if it is also the subject of the scheduled October 21, 2015 featured article or the October 21, 2015 featured picture.
To report an error when this appears on the Main Page, see Main Page errors. Please remember that this list defers to the supporting articles, so it is best to achieve consensus and make any necessary changes there first.
Use only ONE image at a time
Overture, can-can section
|Overseas Chinese Day in Taiwan||refimprove, and Overseas Chinese does not mention this date|
|1520 – The islands of Saint Pierre and Miquelon were discovered by Portuguese explorer João Álvares Fagundes near Canada, who named them "Islands of the 11,000 Virgins".||outdated|
|1824 – English stonemason, bricklayer and inventor Joseph Aspdin patented Portland cement, currently the most common type of cement in general usage in many parts of the world.||Aspdin: needs more footnotes; Cement: unreferenced section|
|1966 – A coal tip fell on the village of Aberfan, Wales, killing 144 people, mostly schoolchildren.||external links|
|1969 – Siad Barre became President after a military coup in Somalia.||already featured on January 26|
- 1096 – The Seljuk forces of Kilij Arslan destroyed the army of the People's Crusade as it marched toward Nicaea.
- 1600 – Tokugawa Ieyasu defeated the leaders of rival Japanese clans at the Battle of Sekigahara in what is now Sekigahara, Gifu, clearing the path for him to form the Tokugawa shogunate.
- 1858 – French composer Jacques Offenbach's operetta Orpheus in the Underworld, featuring music most associated with the can-can (audio featured), was first performed at the Théâtre des Bouffes-Parisiens in Paris.
- 1867 – The first of the Medicine Lodge Treaties was signed between the United States and several Native American tribes in the Great Plains, requiring them to relocate to areas in present-day western Oklahoma.
- 1921 – George Melford's wildly successful silent film The Sheik, which would propel its leading actor Rudolph Valentino to stardom, premiered.
- 1950 – Korean War: British and Australian troops of the 27th British Commonwealth Brigade engaged in heavy fighting with North Korean forces in the Battle of Yongju.
- 1959 – The Solomon R. Guggenheim Museum, designed by American architect Frank Lloyd Wright, opened in New York City.
- 1983 – At the seventeenth General Conference on Weights and Measures, the length of a metre was redefined as the distance light travels in vacuum in 1/299,792,458 of a second.
- 1987 – Sri Lankan Civil War: Indian Army soldiers, belonging to the Indian Peace Keeping Force, entered the Jaffna Teaching Hospital in Jaffna and began killing at least 60 patients, nurses, doctors and other staff members.
- 1805 – Napoleonic Wars: Lord Nelson signalled "England expects that every man will do his duty" to the rest of his Royal Navy forces before they defeated Pierre-Charles Villeneuve and his combined French–Spanish navy at the Battle of Trafalgar off the coast of Spain's Cape Trafalgar.
- 1854 – Florence Nightingale (pictured) and a staff of 38 nurses were sent to Turkey to help treat wounded British soldiers fighting in the Crimean War.
- 1910 – HMS Niobe arrived in Halifax Harbour to become the first large ship of the Royal Canadian Navy.
- 1944 – World War II: German forces surrendered to American troops, ending the three-week-long Battle of Aachen.
- 1978 – After reporting contact with an unidentified aircraft, Frederick Valentich disappeared in unexplained circumstances while piloting a Cessna 182L light aircraft over the Bass Strait to King Island, Australia.