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

Other days

eat what you want

Eat What You Want Day
blanket fort

Blanket Fort Day
offer

Offer Day
singles

Singles Day
boy friend

Boy Friend Day
hiv awareness

Hiv Awareness Day
african immigrant and refugee hiv and hep awareness

African Immigrant And Refugee Hiv And Hep Awareness Day
promposal

Promposal Day
martini

Martini Day
first love

First Love Day