IWD is a day that has origins in USA, particularly in New York where it was first organised by Socialist Party of America, not kidding. It was some kind of remembrance of 1908: “strike of the International Ladies Garment Workers Union”.
Two years later in International Women’s Conference, it was proposed to establish “International Woman’s Day”. Following years, millions of people started to celebrate this date with lot of demonstrations and people carrying banners.
For example on March 8 women in Saint Petersburg demonstrated for the end of WWI.
Nowadays every year we have a theme for the celebration. Usually it has to do with gender equality. This years it is: Planet 50-50 by 2030: Step It Up for Gender Equality
I wish you happy IWD since I believe that it will make lot of people happy!