Oops, it doesn't look like 'investigation day' is a national day..

Other days

aloxolt

Aloxolt Day
tulip

Tulip Day
bonang

Bonang Day
promposal

Promposal Day
self care

Self Care Day
cuddle up

Cuddle Up Day
reading

Reading Day
bow tie

Bow Tie Day
singles

Singles Day
nae nae

Nae Nae Day