As an example, the [9/11 Memorial and Museum](https://en.wikipedia.org/wiki/9/11_Tribute_Museum) opened 5 years after 9/11. The [National World War I Museum](https://en.wikipedia.org/wiki/National_World_War_I_Museum_and_Memorial) opened 8 years after the end of World War I. Was there ever a museum that opened after an even shorter time period following a major historical event?

The definition of an "event": a historical occurrence that wasn't easily predictable in advance. For example, Nixon's Presidential Library wouldn't count as commemorating the "event" of Nixon's presidency because it was entirely predictable that *someone* will be elected President in 1969 and that this someone will end up having a library.

Update: the definition of "opening" is that a member of the general public was able to attend said museum and see at least one exhibit.