International Women's Day is an annual day that began

 International Women's Day is an annual day that began with the labor movement that was later recognized by the United Nations. 

The seed was planted in 1908 when 15,000 women demonstrated in New York City for shorter working hours, better pay and the right to vote. .

A year later, the Socialist Party of America announced the first National Women's Day. She suggested this at the Conference of Working Women in Copenhagen in 1910. 100 women from 17 countries participated in that conference. And they unanimously agreed to that suggestion.