5 observances land on 15 December. We have not found a recorded founder for any of them.
| Observance | Declared by | First year | Source |
|---|---|---|---|
| Bill of Rights Day United States | no record | — | — |
| Homecoming Day Alderney | no record | — | — |
| Kingdom Day Netherlands | no record | — | — |
| Zamenhof Day International Esperanto Community | no record | — | — |
| World Turkic Language Family Day UNESCO | no record | — | — |
"No record" means we could not find one, not that none exists. Where a founder is named, the source is named with it.
Who decides these? Nobody official. A brand, a trade body, a government, or one person with a website. Most are simply asserted and then repeated until they look official. Here, whoever names it first.
Nobody has ever named 15 December here. The next one is Tuesday, 15 December 2026.
Tuesday, 15 December 2026 has no name yet. It costs $2.