Oops, it doesn't look like 'monument to host day' is a national day..

Other days

one

One Day
bonang

Bonang Day
latina equal pay

Latina Equal Pay Day
buddy

Buddy Day
ruby

Ruby Day
tell a fairytale

Tell A Fairytale Day
mean girls

Mean Girls Day
brow

Brow Day
hoodie

Hoodie Day
martini

Martini Day