| date | entity | event | name |
|---|---|---|---|
| 21/10/2009 | city | date founded | Saint-Norbert-d'Arthabaska, Quebec |
| 21/10/1937 | former country | data end | Sovereign Council of Asturias and León |
| 21/10/2010 | operating system | date released | Windows Phone |
| 21/10/1930 | organization | date founded | Horta Football Association |
| 21/10/2011 | organization | date founded | Qt Project |