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

Other days

African Immigrant And Refugee Hiv And Hep Awareness Day

Promposal Day

Kiss A Brunette Day

Ponytail Day

Tell Ur Crush You Like Them Day

Chocolate Milkshake Day

First Love Day

Law Day

Cuddle Up Day

Polyamory Day