noun
commemoration
kuh-mem-uh-RAY-shun/kəˌmeməˈreɪʃn/
A tribute honoring the memory of a person or event.
The town holds a commemoration for the victims each year.

Etymology
With an intensive prefix, the reminding root makes commemoration an act of calling something to mind. Its ceremonial sense turns that remembrance into an organized observance.
In context
I attended a Regency era ball in Helsinki Alexander's for commemoration of an actual historical event when Tsar Alexander the first visited Helsinki in 1809
More examples
- Survivors gather at the bridge for a quiet commemoration.
- The museum opens an exhibit in commemoration of the landing.
- Annual commemorations keep the workers' sacrifice from being forgotten.
Forms
commemoration · commemorations
commemorate verb — Honor a person or event through remembrance.
commemorative adjective — Intended to honor someone or something remembered.