| date | entity | event | name |
|---|---|---|---|
| 21/12/1840 | encyclical | date | Augustissimam beatissimi |
| 21/12/2013 | file format | date released | Open Game Engine Exchange |
| 21/12/2010 | flag | date Adopted | Flag of La Plata |
| 21/12/2001 | protected area | date founded | Forollhogna National Park |
| 21/12/1962 | protected area | date founded | Fort De Soto Park |