| date | entity | event | name |
|---|---|---|---|
| 23/05/1989 | protected area | date founded | Tinguá Biological Reserve |
| 23/05/1947 | organization | date founded | Movistar Colombia |
| 23/05/2003 | organization | date founded | Sankalp India Foundation |
| 23/05/1932 | organization | date founded | Federação Paranaense de Atletismo |
| 23/05/1917 | organization | date founded | Swedish Linnaeus Society |