5 observances land on 18 April. We have not found a recorded founder for any of them.
| Observance | Declared by | First year | Source |
|---|---|---|---|
| Coma Patients' Day Poland | no record | — | — |
| Friend's Day Brazil | no record | — | — |
| International Day For Monuments and Sites | no record | — | — |
| Invention Day Japan | no record | — | — |
| World Amateur Radio Day | 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 18 April here. The next one is Sunday, 18 April 2027.
Sunday, 18 April 2027 has no name yet. It costs $2.