Oops, it doesn't look like 'monument on a dark day' is a national day..

Other days

promposal

Promposal Day

special education

Special Education Day

singles

Singles Day

tell a fairytale

Tell A Fairytale Day

believe

Believe Day

Me Day

first love

First Love Day

brow

Brow Day

hoodie

Hoodie Day

tell ur crush you like them

Tell Ur Crush You Like Them Day